Article

Developmental continuity? Crawling, cruising, and walking

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Abstract

This research examined developmental continuity between "cruising" (moving sideways holding onto furniture for support) and walking. Because cruising and walking involve locomotion in an upright posture, researchers have assumed that cruising is functionally related to walking. Study 1 showed that most infants crawl and cruise concurrently prior to walking, amassing several weeks of experience with both skills. Study 2 showed that cruising infants perceive affordances for locomotion over an adjustable gap in a handrail used for manual support, but despite weeks of cruising experience, cruisers are largely oblivious to the dangers of gaps in the floor beneath their feet. Study 3 replicated the floor-gap findings for infants taking their first independent walking steps, and showed that new walkers also misperceive affordances for locomoting between gaps in a handrail. The findings suggest that weeks of cruising do not teach infants a basic fact about walking: the necessity of a floor to support their body. Moreover, this research demonstrated that developmental milestones that are temporally contiguous and structurally similar might have important functional discontinuities.

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... Here, we investigated the role of experience in infants' acquisition of behavioral flexibility by focusing on "cruising"-when pre-walking infants step sideways using an environmental support (coffee table, couch, etc.) to keep balance. Cruising is a brief, transitory skill that overlaps with crawling and disappears after infants can walk [17,18]. Like walking, cruising involves an upright posture, and like crawling, cruising involves movements of all four limbs; indeed, cruising may be considered functionally as "upright crawling" [17]. ...
... Cruising is a brief, transitory skill that overlaps with crawling and disappears after infants can walk [17,18]. Like walking, cruising involves an upright posture, and like crawling, cruising involves movements of all four limbs; indeed, cruising may be considered functionally as "upright crawling" [17]. Crawling experience leads to a consistent anti-phase pattern where diagonal limbs (right arm, left leg, etc.) move together [10,19,20], but effects of experience on interlimb coordination in cruising are unclear [21,22]. ...
... Crawling experience leads to a consistent anti-phase pattern where diagonal limbs (right arm, left leg, etc.) move together [10,19,20], but effects of experience on interlimb coordination in cruising are unclear [21,22]. Moreover, unique to cruising, infants must incorporate environmental support into their coordination patterns [21], and the nature of the support (distance between furniture, height of the table, compliance of the couch, etc.) influences which patterns are viable [17,23]. ...
Article
Flexibility and generativity are fundamental aspects of functional behavior that begin in infancy and improve with experience. How do infants learn to tailor their real-time solutions to variations in local conditions? On a nativist view, the developmental process begins with innate prescribed solutions, and experience elaborates on those solutions to suit variations in the body and the environment. On an emergentist view, infants begin by generating a variety of strategies indiscriminately, and experience teaches them to select solutions tailored to the current relations between their body and the environment. To disentangle these accounts, we observed coordination patterns in 11-month-old pre-walking infants with a range of cruising (moving sideways in an upright posture while holding onto a support) and crawling experience as they cruised over variable distances between two handrails they held for support. We identified infants' coordination patterns using a novel combination of computer-vision, machine-learning, and time-series analyses. As predicted by the emergentist view, the least experienced infants generated multiple coordination patterns inconsistently regardless of body size and handrail distance, whereas the most experienced infants tailored their coordination patterns to body-environment relations and switched solutions only when necessary. Moreover, the beneficial effects of experience were specific to cruising and not crawling, although both skills involve anti-phase coordination among the four limbs. Thus, findings support an emergentist view and suggest that everyday experience with the target skill may promote "learning to learn," where infants learn to assemble the appropriate solution for new problems on the fly.
... Como os autores pontuam, tradicionalmente, estudava-se a marcha em linha reta e em solo plano -deixando de evidenciar processos como as quedas, a irregularidade e intermitência de ações locomotoras ao longo do tempo, a aquisição e experiência (ou falta dela) com diversos marcos motores (ie. Engatinhar e andar com apoio) e a preferência do bebê em utilizar-se de diferentes estratégias para se locomover (Adolph, Berger & Leo, 2011), etc. Mais do que isso, Kopp (2011) aponta a transformações sócio--históricas que têm afetado, por um lado, os espaços e os tipos de estímulos disponibilizados ao desenvolvimento motor da criança; e, por outro lado, concepções e práticas parentais, as quais têm levado, por exemplo, a que se posicione as crianças no colo, prioritariamente de modo mais ereto. Com isso, discute-se e como as próprias faixas etárias para aquisições motoras passaram a serem revistas, apontando à necessidade de se considerar a dinâmica contemporânea do desenvolvimento locomotor. ...
... O marco "cruising" se refere a um deslocamento que envolve tanto o apoio inferior dos pés sobre o solo, como o apoio superior das mãos sobre a mobília, corrimão ou outros (Berger, Chan & Adolph, 2014). Ele é comumente referido na literatura como uma transição entre o andar e o engatinhar (Adolph, Berger & Leo, 2011;Atun-Einy, Berger & Sher, 2012). Outro aspecto importante apontado em relação a este marco é que ele pode vir a afetar a disposição social do bebê devido à configuração postural bípede, a qual confere ao bebê uma reorganização espacial e perceptual. ...
... Primeiramente, o móvel que Catarina usa de apoio permite diversas possibilidades de locomoção e interação. Por ter o formato de um túnel, apresenta a possibilidade de que se percorra seu interior; ainda, tal formato cria um vão entre as laterais das grades, com uma lacuna para o apoio das mãos (Adolph, Berger & Leo, 2011). Ao movimento de entrar no túnel é necessário que a criança estique o braço a uma maior distância e dê passos com menor superfície de apoio para tocar a outra parede. ...
Article
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O desenvolvimento locomotor do bebê é modulado por processos perceptuais/sociais/interativos. Porém, articulação desses elementos e sua complexidade em ambientes naturalísticos de creche, onde pares de bebês são importantes parceiros, faz-se pouco claro. Assim, objetivou-se estudar entrelaçamento de processos locomotores relacionados a interações de bebês pares de idade. Conduziu-se estudos de caso múltiplos, baseados em pressupostos histórico-culturais, analisando-se videogravações de bebês em creche. Dois episódios são analisados: um em que três bebês engatinham/param em função do movimento de uma bola; outro em que o andar com apoio é dificultado/reconfigurado na presença do par. A triangulação atencional associado às (in)capacidades motoras conferem dinâmicas diferenciadas ao movimento, dando-se como fluxo relacional. Mediação do espaço físico e concepções educativas são discutidas.
... However, age norms are problematic for comparing one typically-developing infant to another because the "average" infant is no infant at all. Individual babies carve out their own path to upright mobility; they can skip milestones, revert to earlier milestones, and achieve milestones in various orders (Adolph et al., 2011;Gesell, 1939Gesell, , 1946. Published age norms (e.g., Alberta Infant Motor Scale) and standards (World Health Organization) reflect only a small subset of the world's population and a small-likely outdated-slice of human history (DeMasi et al., 2023;Karasik et al., 2010;Karasik & Robinson, 2022). ...
... To combat gravity, infants routinely exploit external supports for upright locomotion. Pre-walkers take steps while holding a caregiver's hand or pushing a "walker" or chair, and they "cruise" sideways while holding furniture for support (Adolph et al., 2011;Haehl et al., 2000). With experience, legs strengthen, balance improves, and infants' need for external support decreases. ...
Article
The development of locomotion can be described by its form (i.e., gait) and its function (i.e., mobility). Both aspects of locomotion improve with experience. Traditional treatises on infant locomotion focus on form by describing an orderly progression of postural and locomotor milestones en route to characteristic patterns of crawling and walking gait. We provide a traditional treatment of gait by describing developmental antecedents of and improvements in characteristic gait patterns, but we highlight important misconceptions inherent in the notion of “milestones”. Most critically, we argue that the prevailing focus on gait and milestones fails to capture the true essence of locomotion—functional mobility to engage with the world. Thus, we also describe the development of mobility, including the use of mobility aids for support and propulsion. We illustrate how infants find individual solutions for mobility and how the ability to move cascades into other domains of development. Finally, we show how an integration of gait and mobility provides insights into the psychological processes that make locomotion functional. This article is categorized under: Psychology > Motor Skill and Performance Psychology > Development and Aging
... Neural circuits for controlling locomotion are already established in early infancy 18,19 and their functioning is also manifested in a number of locomotor precursors [20][21][22] . A developmental continuity of locomotor-related movements 23 is central for establishing independent mobility and the emergence of different gait modes 24 . In particular, changes of walking direction are common in everyday life, and can have a significant effect on children's ability to manage the daily life. ...
... In particular, changes of walking direction are common in everyday life, and can have a significant effect on children's ability to manage the daily life. In particular, cruising (moving sideways holding onto furniture for support) represents an important developmental activity during learning to walk that infants start before the onset of independent walking 23 . Walking sideways (SW) necessitates a reorganization of muscle activity patterns 25 and may reinforce muscles involved in the frontal plane control thus also improving balance, flexibility, and spatial awareness. ...
Article
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Switching locomotion direction is a common task in daily life, and it has been studied extensively in healthy people. Little is known, however, about the locomotor adjustments involved in changing locomotion direction from forward (FW) to sideways (SW) in children with cerebral palsy (CP). The importance of testing the ability of children with CP in this task lies in the assessment of flexible, adaptable adjustments of locomotion as a function of the environmental context. On the one hand, the ability of a child to cope with novel task requirements may provide prognostic cues as to the chances of modifying the gait adaptively. On the other hand, challenging the child with the novel task may represent a useful rehabilitation tool to improve the locomotor performance. SW is an asymmetrical locomotor task and requires a differential control of right and left limb muscles. Here, we report the results of a cross-sectional study comparing FW and SW in 27 children with CP (17 diplegic, 10 hemiplegic, 2–10 years) and 18 age-matched typically developing (TD) children. We analyzed gait kinematics, joint moments, EMG activity of 12 pairs of bilateral muscles, and muscle modules evaluated by factorization of EMG signals. Task performance in several children with CP differed drastically from that of TD children. Only 2/3 of children with CP met the primary outcome, i.e. they succeeded to step sideways, and they often demonstrated attempts to step forward. They tended to rotate their trunk FW, cross one leg over the other, flex the knee and hip. Moreover, in contrast to TD children, children with CP often exhibited similar motor modules for FW and SW. Overall, the results reflect developmental deficits in the control of gait, bilateral coordination and adjustment of basic motor modules in children with CP. We suggest that the sideways (along with the backward) style of locomotion represents a novel rehabilitation protocol that challenges the child to cope with novel contextual requirements.
... Most of what is known about these precursor behaviors to walking has been drawn primarily from laboratory experiments that test infants' understanding of affordances for locomotion (i.e., possibilities for action based on the relations between body and environment; Gibson, 1979) and studies of the biomechanics of movement. This wealth of information about the broader characteristics of infants' movements has provided important insights into their abilities to navigate various terrains (e.g., Adolph, 1997;Adolph et al., 1998Adolph et al., , 2011Berger et al., 2014) and to coordinate their limbs in functional ways (e.g., Freedland & Bertenthal, 1994;Haehl et al., 2000;Ossmy & Adolph, 2020). Moreover, research suggests that the ages at which infants acquire motor skills are interconnected; infants who crawl earlier tend to cruise and walk earlier . ...
... This investigation focused on a subset of home observations that spanned the two months prior to the onset of walking for each infant (see Figure 1). We selected this observational window as it encompasses the developmental period in which infants typically demonstrate multiple forms of independent locomotion before the emergence of walking (e.g., crawling, cruising; Adolph et al., 2011). ...
Article
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Many different pathways can lead to the same result or developmental outcome. What are the developmental routes that result in the onset of walking? In this longitudinal study, we documented patterns of infant locomotion during everyday activities at home for 30 prewalking infants. Using a milestone‐based design, we focused on observations spanning the two months before the onset of walking (M age at walk onset = 11.98 months, SD = 1.27). We examined how much time infants spent in motion and when they moved, whether they were more likely to do so while prone (crawling) or upright with support (cruising or supported walking). Results showed immense variability in infants’ practice regimes en route to walking—some infants spent relatively similar amounts of time crawling, cruising, and supported walking at each session, others preferred one method of travel over the alternatives, and some switched between different types of locomotion from session to session. In general, however, infants spent a larger share of their movement time in upright positions compared to prone. Finally, our densely sampled dataset revealed a clear feature of locomotor development: infants follow many distinct and variable paths to walk onset, regardless of the age at which it is attained.
... Bebés que se deslocam no solo exibem mais comportamentos de afeto (8) e acompanham mais expressões e gestos (9). Em média, começam a deslocar-se no solo entre 6 e 9 meses, mas alguns nunca o fazem e alguns fazem-no ao mesmo tempo que começam a andar (10). Há poucos estudos sobre diversidade de modos de deslocação no solo (MDS), baseando-se principalmente nos padrões de coordenação entre membros (mãos e joelhos no solo em quadrupedia) para uma deslocação mais eficiente (11), ou em 3 variantes do gatinhar (12). ...
... Para análise de associação entre idades foi usada a correlação Spearman (ρ) e intervalo de confiança (IC), com sinal igual, a 95% (13). Para comparação entre grupos foi usado o teste Kruskall-Wallis (H), e o teste Mann-Whitney (Z), teste exato Monte Carlo, com correção Bonferroni, e estimativa efeito do tamanho r (r) e Cohen' d (d).RESULTADOSForam identificados 20 MDS (frequência e percentagem):-Gatinhar-mãos e pernas no chão, alterna movimento de mão e perna opostos (40-76,9%); -Reptil-deitado/a de barriga para baixo, alternando movimento de braços e membros inferiores(16-30,8%); -Rolar-Deitado/a, rola no eixo longitudinal do corpo sucessivamente (13-25%); -Misto 4 apoios-Como no gatinhar, mas com perna e pé contralaterais no chão (12-23,1%); -Minhoca-Deitado/a em decúbito ventral, dobra membros inferiores e depois estende-os, empurrando chão com os pés (10-19,2%);-De costas-Deitado/a em decúbito dorsal, empurra com os pés (9-17,3%); -Sentado Membros inferiores Laterais (Remar)-Dobrando os membros inferiores para um lado e para o outro, podendo haver apoio lateral alternado de cada mão (7-13,5%); -Sentado com Tronco (Leque)-Mantendo membros inferiores esticados e afastados, balanceia o tronco para trás e para a frente(7)(8)(9)(10)(11)(12)(13)5); ...
Chapter
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The present study aimed to analyze the diversity of modes of movement on the ground (commonly named as crawling) in early childhood and interaction with context constraints, through a closed pictorial questionnaire for mothers and fathers (N = 52). Twenty different modes of travel on the ground were identified, with an average of 3.04 (±3.33) per child. Children who were encouraged to walk without using the spider were also those that revealed more ways to move around on the ground. The more advanced the position in the fratry, without the use of a spider, the earlier the age of onset of displacement in the ground. Thus, there is a great diversity of modes of travel on the ground, and each child can use more than one. Therefore, the self-organized motor diversity is already evident in early childhood, being enhanced by a more advanced brotherwood position and inhibited by the use of the spider-
... Crawling is a key step in the locomotion evolution for most of the babies, which concludes when the infant is able to walk. For approximately 50% of the babies [1], crawling behaviour usually starts at the age of 8 months, but it can also be later or never happening. It is an issue of interest for paediatric professionals and parents as it is a common concern about children mobility development. ...
... These sessions, commonly known as "tummy time", help babies to strengthen and control better key muscles for crawling, such as the ones in their neck and shoulders, among others [4]. Additionally, early promotion of "tummy time" has been shown to be effective in improving feeding practices in infants between 1 and *This work was not supported by any organization 1 12 months [5], as well as reducing the motor delay in young infants with Down syndrome [6]. • And, finally, positioning a certain toy out of the reach of babies encourages them to move towards it [7]. ...
Preprint
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This article introduces "Baby Robot", a robot aiming to improve motor skills of babies and toddlers. Authors developed a car-like toy that moves autonomously using reinforcement learning and computer vision techniques. The robot behaviour is to escape from a target baby that has been previously recognized, or at least detected, while avoiding obstacles, so that the security of the baby is not compromised. A myriad of commercial toys with a similar mobility improvement purpose are into the market; however, there is no one that bets for an intelligent autonomous movement, as they perform simple yet repetitive trajectories in the best of the cases. Two crawling toys -- one in representation of "Baby Robot" -- were tested in a real environment with respect to regular toys in order to check how they improved the toddlers mobility. These real-life experiments were conducted with our proposed robot in a kindergarten, where a group of children interacted with the toys. Significant improvement in the motion skills of participants were detected.
... Adolph and colleagues suggest that each motor developmental milestone is a gradual progression in balance control that requires different parameters 86,[92][93][94] . ...
... They argue that sitting, crawling and walking require different muscle groups, different vantage points and different somatosensory input. Infants continually, albeit subconsciously, alter their balance and, as a result, learn the maximum threshold of postural sway needed to successfully execute each of these skills 86,[92][93][94] . This is consistent with evidence from the World Health Organisation (WHO) that has shown that at least 90% of children achieved milestones in a common sequence: sitting, standing with help, walking with help, standing unassisted, and walking unassisted 89 . ...
Conference Paper
Balance ability is a crucial component of everyday life, underlying physical movement at all stages in life. Despite this, balance is an overlooked aspect of physical health and ageing, with minimal evidence of how factors throughout life are associated with balance ability. This PhD thesis used a life course approach to investigate how factors across life contribute to standing balance in mid and later life, and to examine associations between balance ability and subsequent falls risk. Data from the MRC National Survey of Health and Development (NSHD) were used. NSHD is a nationally representative sample of 5362 males and females, born in England, Scotland and Wales in March 1946 and followed up to 24 times across life. One-legged balance time with eyes closed was assessed at ages 53, 60-64 and 69 (n=3111 individuals with a balance time at one or more age). Analytical methods included multilevel models, structural equation models, linear and logistic regressions and receiver-operating characteristic analyses. In adulthood, disadvantaged socioeconomic position, poor health and adverse health related behaviours were associated with poorer balance ability (Chapter 3). In childhood, disadvantaged socioeconomic position, lower cognitive ability, slower coordination and early or late attainment of motor milestones were associated with poorer balance ability (Chapter 3, 4). Across several domains, higher cognitive ability in midlife was associated with better balance ability (Chapter 5). The association between verbal memory and subsequent balance ability was unidirectional, with some evidence of more complex bidirectional associations with search speed (Chapter 6). Most factors across life demonstrated changing patterns of association with balance with age. Finally, balance ability was associated with subsequent falls, although the one-legged stand did not appear to be a sensitive prognostic indicator of fall risk (Chapter 7). Better understanding of the socioeconomic, cognitive, behavioural and health pathways across life which relate to subsequent balance ability, identified in this thesis, provides an opportunity to intervene earlier in life to minimise, prevent or delay balance impairment or decline.
... Where does locomotor behavior start? This question, suggesting a developmental continuity, is a central and long-standing issue (Adolph et al., 2011). Continuity supports the idea that new skills grow from the seeds of prior precursors. ...
... Humans start to walk significantly later than most animals (Garwicz et al., 2009), and infants discover an array of idiosyncratic solutions for mobility (Patrick et al., 2012; Figure 1C) before having sufficient axial and limb muscles strength and balance control to walk (e.g., McGraw, 1945;Thelen and Ulrich, 1991;Bril and Breniere, 1992;Guillaud et al., 2020). While strategies such as crawling or cruising are still widely depicted in modern ''milestone'' and assessment charts (Piper and Darrah, 1994;Adolph and Robinson, 2013;Adolph et al., 2018), infants often deviate from common trajectories and develop individual differences in development (Adolph et al., 2011;Atun-Einy et al., 2012). Conversely, in early infancy, precursory forms of spontaneous movements ( Figure 1C) appear as more obvious obligatory stages in the development of locomotion. ...
Article
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This mini-review focuses on the emergence of locomotor-related movements in early infancy. In particular, we consider multiples precursor behaviors of locomotion as a manifestation of the development of the neuronal networks and their link in the establishment of precocious locomotor skills. Despite the large variability of motor behavior observed in human babies, as in animals, afferent information is already processed to shape the behavior to specific situations and environments. Specifically, we argue that the closed-loop interaction between the neural output and the physical dynamics of the mechanical system should be considered to explore the complexity and flexibility of pattern generation in human and animal neonates.
... That the infant motor development sequence progresses near universality in a relatively invariant order although with variable timing in biological age (BA) and chronological age (CA) continues as a contemporary view (Adolph, Berger, & Leo, 2011;Adolph & Franchak, 2017;Bril, 2018;Thelen & Smith, 1994;Touwen, 1976; Van der Geert, Savelsbergh, & Van der Maas, 1999, WHO Multicentre Growth Reference Study Group, 2006), albeit under different theoretical frameworks from the early infant studies. Figure 1, adapted from the classic study of Shirley (1931), shows the average chronological time course of the emergence of the onset instantiations of postural, locomotive, and manipulative actions during infancy. ...
... One of the more well-known intermediate action examples is 'cruising', where the infant between standing and walking supports him or herself by hand contact with objects (chairs, tables, etc.) to transport via supported walking in the environment. Cruising is another example of infant postural support facilitating execution and performance of other action categories (Adolph et al., 2011). ...
Article
A review and synthesis of the literature on the learning and development of motor skills supports the postulation that whether a motor skill can be deemed fundamental is dependent on the collective presence of three conditions: (i) uniqueness to the movement pattern and/or outcome; (ii) near universality of the functional outcome in the healthy population; (iii) capacity to act as an antecedent influence supporting generalization to a large and broad set of perceptual-motor skills. Within this framework, it is proposed that the infant motor development sequence underpinning upright posture (e.g., sitting, bipedal standing), locomotion (e.g., walking, running), and object-interaction (e.g., grasping) represents the minimum set of fundamental motor skills from which all other skills evolve with over the lifespan. This position is in contrast to the views of many students of motor development and learning who describe numerous skills that typically emerge in the ∼2- to 18-year-old range as fundamental but do not meet the criteria outlined here to be fundamental. It is proposed that these be labeled as core developmental activities having a more restricted but still practically relevant influence on the acquisition of and generalization to other motor skills.
... Accordingly, postural development was considered as an ordered, age-related mastery of a series of "motor milestone" stages such as crawling, creeping, sitting, pull-to-stance behavior, cruising, and independent standing and walking (McGraw, 1932;Gesell, 1946). However, it is now acknowledged that infants acquire postural skills in quite different orders and skip or return to earlier stages depending on individual bodily, environmental and cultural factors (Adolph et al., 2011;Atun-Einy et al., 2012). Accordingly, the development of independent posture and locomotion skills is currently considered a non-linear process with phases of transitions that are determined by a complex interaction between the nervous and musculoskeletal systems of the infant as well as task-specific requirements and changing environmental conditions (Woollacott et al., 1996;Smith and Thelen, 2003). ...
... Before learning to walk independently, infants adopt a variety of supported upright walking styles. These include cruising while grasping stable objects such as furniture, first with both hands for support and later with support by only one hand (Adolph et al., 2011). Different stages of locomotor development, such as crawling or cruising, do not occur in a fixed order but may be adopted concurrently or even in reverse order. ...
Chapter
Synopsis Postural control is a complex sensorimotor behavior that maintains balance by counteracting gravitational forces and by anticipating postural challenges induced by external demands and perturbations. Postural control is based on biomechanical constraints of the body with its bones, joints, ligaments and muscles. Spinal and supraspinal neuronal networks with strong sensory contributions control anti-gravity muscle activity. Postural control in bipedal humans has some distinctive features, including the larger vestibular contribution to balance and the more prominent supraspinal control of posture. Supraspinal aspects of postural control in humans are also reflected by their sensitivity to cognitive challenges.
... Moreover, cruising serves the same general function as walking (upright locomotion), it is temporally contiguous with walking (infants cruise for several weeks before they walk), and it shares structural similarities with walking (upright, alternating legs). However, there is a critical functional discontinuity between cruising and walking: Experience cruising does not teach infants that they need a floor to support their body (Adolph, Berger, & Leo, 2011). In this sense, cruising does not prepare infants to walk and is not "proto-walking." ...
Article
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In reviewing work on motor development, we aim to interest readers from every area of developmental science. How so? Rather than writing a boutique chapter geared toward researchers who specialize in motor development, we use research on motor development to address central concepts and methodological issues that have challenged developmental scientists for centuries. We argue that the study of motor development can yield fresh insights into processes of learning and development. Motor behavior can take the lead in developmental research and partner with work in seemingly disparate domains by considering developmental phenomena as embodied in the reality of children’s growing bodies, embedded in the prac- tical exigencies of a physical environment, intimately involved in social interactions, and reflective of cultural influences. Our strategy is to focus on 10 general developmental issues that are broadly relevant to developmental science and aptly illustrated with examples drawn from research on motor development. The issues are loosely organized into framing sections on embodied movement, embedded action, and enculturated interaction.
... While encouraged by the cross-task and cross-setting consistencies in our results, we acknowledge that the cross-sectional design has some limitations. 80 The discretization into age groups that were necessary for ll OPEN ACCESS 14 iScience 26, 106038, February 17, 2023 iScience Article comparing cross-sectional groups is a case in point. Future studies could increase the age resolution to scrutinize the transition to adult-like performance in a more continuous manner. ...
Article
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Prediction is critical for successful interactions with a dynamic environment. To test the development of predictive processes over the life span, we designed a suite of interceptive tasks implemented as interactive video games. Four tasks involving interactions with a flying ball with titrated challenge quantified spatiotemporal aspects of prediction. For comparison, reaction time was assessed in a matching task. The experiments were conducted in a museum, where over 400 visitors across all ages participated, and in a laboratory with a focused age group. Results consistently showed that predictive ability improved with age to reach adult level by age 12. In contrast, reaction time continued to decrease into late adolescence. Inter-task correlations revealed that the tasks tested different aspects of predictive processes. This developmental progression complements recent findings on cerebellar and cortical maturation. Additionally, these results can serve as normative data to study predictive processes in individuals with neurodevelopmental conditions.
... Current evidence suggests that contrary to the predictions of neuromaturational theories, crawling experience does not contribute to the devel-opment of functional walking. [35][36][37] However, some therapists claim that crawling is necessary for the development of perceptual, cognitive, and fine motor skills in infancy and childhood. Classic theories regarding the role of crawling experience in building developmental skills are largely unsubstantiated by empirical research. ...
Article
Purpose: In early 2022, the Centers for Disease Control and Prevention (CDC) updated their developmental surveillance milestone checklists. The purpose of this article is to clarify and interpret the updates from a physical therapist perspective and to discuss implications of the new milestones for physical therapists. Summary of key points: The CDC's updated checklists provide clear, consistent, easy to use, and evidence-based developmental milestones to prompt discussion with families. The new checklists do not represent a lowering of standards and will likely increase, not decrease, referrals for screening, evaluation, and services. Crawling has been removed from the milestone checklists, as the current evidence suggests that crawling is highly variable and not essential for development. Conclusions and recommendations for clinical practice: The updated milestone checklists will facilitate bringing vital services to children who need them. Physical therapists should support our primary care colleagues in implementing this useful program.
... They might search for specific techniques for movement patterns that work for the task set or discover different ways to vary or generalize the coordination pattern in relation to broader physical activity contexts in games (Vereijken and Whiting, 1990;Chow et al., 2016). Rather than the practitioner informing students what movements to perform, what techniques to use, and the specific outcome sought, the children search the perceptual-motor workspace in relation to their individual capabilities and what the environment affords to discover the emergence of movement patterns or activities that they practice (Newell et al., 1989;Newell, 1996;Adolph et al., 2011). ...
Article
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In this paper we examine the role of instructional strategies as constraints within a discovery learning framework for the teaching of open skill team ball games to elementary school-aged children. The cohesive and adaptive integration of constraints (individual, environment, and task) by practitioners of movement and physical activity (instructor, teacher, coach) is proposed as the pathway to exploiting the effectiveness of guided discovery learning. The qualitative analysis of the practical instantiations of this framework by expert teachers is examined with respect to the learning of open skill team invasion games (e.g., basketball, soccer). The primary constraints to action in this learning-teaching developmental framework are coordinated so as to keep the self-organization of skill development (movement pattern and tactics) continually evolving, while preserving the child’s motivation and enjoyment for the expanding repertoire and performance capacity of his/her perceptual-motor skills. In this open skill and elementary school age-related context, generality and specificity are both necessary and complementary in the expression of task, skill and practice influences on motor learning and performance.
... The order and timing of motor milestone onsets can vary from infant to infant (e.g., Adolph, Berger, & Leo, 2011;Berger et al., 2007). Because this case study includes just 3 infants, we first confirmed whether their motor skill acquisition was representative of the general population. ...
Article
To systematically examine the relation between motor milestone onset and disruption of night sleep in infancy, three families kept microgenetic, prospective, daily checklist diaries of their infants' motor behavior and sleep (197-313 observation days; 19,000 diary entries). Process control and interrupted time series analyses examined whether deviations from the moving average for night wakings and evening sleep duration were temporally linked to motor skill onset and tested for meaningful differences in individual sleep patterns before and after skill onset. Model assumptions defined skill onset as first day of occurrence or as mastery and moving average windows as 3, 7, or 14 days. Changes in infants' sleep patterns were associated with changing expertise for motor milestones. The temporal relation varied depending on infant and sleep parameter. Intensive longitudinal data collection may increase our understanding of micro-events in infant development.
... Crawling is a four-beat gait, known as most infants' first mobility, and the process of crawling skill acquisition can be interrupted by developmental disorders such as cerebral palsy (CP) (1). Infants with CP usually experience delayed or even lack of crawling skill, which greatly affects the locomotor skill development (2). Based on knowledge of brain plasticity theory (3), with intervention and training at early ages, better prognosis of motor function can be achieved. ...
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When a child shows signs of potential motor developmental disorders, early diagnosis of central nervous system (CNS) impairment is beneficial. Known as the first CNS-controlled mobility for most of infants, mobility during crawling usually has been used in clinical assessments to identify motor development disorders. The current clinical scales of motor development during crawling stage are relatively subjective. Objective and quantitative measures of infant crawling afford the possibilities to identify those infants who might benefit from early intervention, as well as the evaluation of intervention progress. Thus, increasing researchers have explored objective measurements of infant crawling in typical and atypical developing infants. However, there is a lack of comprehensive review on infant-crawling measurement and analysis toward bridging the gap between research crawling analysis and potential clinical applications. In this narrative review, we provide a practical overview of the most relevant measurements in human infant crawling, including acquisition techniques, data processing methods, features extraction, and the potential value in objective assessment of motor function in infancy; meanwhile, the possibilities to develop crawling training as early intervention to promote the locomotor function for infants with locomotor delays are also discussed.
... Nevertheless, after analyzing different or slightly similar samples of babies' crawl there comes a conclusion that, despite the high variability of the applied crawl techniques, all of them have certain constant values inside the interlimb coordination [4]. A pace such as trot prevails even if only three limbs are used [4,5]. It may be confined to the synchronized functioning of limbs, which is possible only when the nervous system is mature. ...
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The biomechanics of military crawl locomotion is poorly covered in scientific literature so far. Crawl locomotion may be used as a testing procedure which allows for the detection of not only obvious, but also hidden locomotor dysfunctions. The aim of the study was to investigate the biomechanics of crawling among healthy adult participants. Eight healthy adults aged 15–31 (four women and four men) were examined by means of a 3D kinematic analysis with Optitrack optical motion-capture system which consists of 12 Flex 13 cameras. The movements of the shoulder, elbow, knee, and hip joints were recorded. A person was asked to crawl 4 m on his/her belly. The obtained results including space-time data let us characterize military crawling in terms of pelvic and lower limb motions as a movement similar to walking but at a more primitive level. Progressive and propulsive motions are characterized as normal; additional right–left side motions—with high degree of reciprocity. It was found that variability of the left-side motions is significantly lower than that of the right side (Z = 4.49, p < 0.0001). The given normative data may be used as a standard to estimate the test results for patients with various pathologies of motor control (ataxia, abasia, etc.).
... They also illustrate the wide range of strategies that typically developing children test and try during development. While the sitting, crawling, and walking strategies that children adopt vary greatly between individuals, they largely converge by 5 years of age to a highly-efficient, stereotypical walking pattern (Ivanenko et al. 2007;Adolph et al. 2011;Karasik et al. 2011). When examining motor control, researchers have used EMG recordings to evaluate how infants and toddlers recruit and coordinate their muscles. ...
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KEY POINTS • Understanding the pathophysiology of skeletal muscle in cerebral palsy (CP) is paramount to developing and applying interventions that reduce contracture while preserving strength. • The ‘traditional view’ whereby spastic/dynamic muscle contractures lead to fixed contractures and bony deformities, is likely incorrect and needs reconsideration in light of recent studies. • Sarcomeres, the basic contractile unit of skeletal muscle, are long and may contribute to the muscle weakness seen in children with CP. • Fixed muscle contractures are related to increases in connective tissue, possibly an adaptive mechanism in the face of increased in vivo muscle tension. • Titin, a spring-like molecule that supports the sarcomere at its ends, is negatively affected in CP, resulting in highly elastic myofibrils and possibly accounting for decreases in eccentric muscle force. • DNA methylation is abnormal in CP and may be responsible for abnormalities in muscle growth and function. • Botulinum neurotoxin A (BoNT-A) causes muscle atrophy and upregulation of fibrofatty connective tissue in animal models, consistent with the lack of functional improvement seen in recent human studies. • Further study is needed to understand the effect of muscle lengthening surgery on function, but changes in fascicle length and pennation angles have been observed In book: Improving Quality of Life for Individuals with Cerebral Palsy through Treatment of Gait Impairment International Cerebral Palsy Function and Mobility SymposiumPublisher: Mac Keith Press / Clinics in Developmental Medicine
... They also illustrate the wide range of strategies that typically developing children test and try during development. While the sitting, crawling, and walking strategies that children adopt vary greatly between individuals, they largely converge by 5 years of age to a highly-efficient, stereotypical walking pattern (Ivanenko et al. 2007;Adolph et al. 2011;Karasik et al. 2011). When examining motor control, researchers have used EMG recordings to evaluate how infants and toddlers recruit and coordinate their muscles. ...
Chapter
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KEY POINTS • Historically, much emphasis on the treatment of children with cerebral palsy (CP) has been on spasticity reduction, but the effects of current treatments on daily life functioning are lacking or highly variable. • Botulinum neurotoxin A (BoNT-A) and selective dorsal rhizotomy (SDR) should be applied in well-selected patients only. • Scientific evidence on the treatment of dystonia in ambulatory patients with CP is almost completely lacking. • Better outcome assessment of current treatment options as well as a search for novel treatment modalities is crucial. http://www.mackeith.co.uk/product-tag/clinics-in-developmental-medicine/
... In questo caso la capacità di prevedere il pericolo del precipizio è legata alla specifica skill del "gattonamento", che il bambino/a padroneggia con esperienza e non è trasferibile ad un'altra skill. Di fronte ad un nuovo compito motorio il bambino/a sembra dover reimparare tutto (Adolph, Berger & Leo, 2011). ...
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Le competenze motorie sono alla base dell’attività fisica del bambino/a e sono molto specifiche. È fondamentale che i bambini/e in età prescolare possano svilupparne il maggior numero possibile. Per questo essi necessitano di tanta attività motoria, ripetuta nel tempo. La competenza motoria permette al bambino/a di comprendere meglio l’ambiente in cui si trova e di riconoscere i pericoli. I bambini/e con basso livello di competenza motoria rischiano di non riconoscere le situazioni pericolose e di non saperle affrontare. Nelle scuole dell’infanzia norvegesi e dei paesi del Nord Europa viene realizzato il “gioco rischioso”, come parte integrante del curricolo scolastico. In questo articolo si è somministrato un questionario sul “Gioco rischioso” a 425 insegnanti delle scuole dell’infanzia italiane, partecipanti ad un progetto nazionale di formazione sull’educazione motoria. Le domande si riferivano alle categorie di “Gioco rischioso” delle scuole dell’infanzia norvegesi. Le insegnanti hanno risposto con una prevalenza significativa di rifiuto delle attività indicate, poiché considerate pericolose e inopportune. Sono state fornite motivazioni relative alla sicurezza, responsabilità, normativa scolastica. Lo studio conferma i principi della motricità ecologica, che considera fondamentale la relazione tra educazione motoria, ambiente fisico, contesto umano, caratteristiche della persona, tipo di compito. Per un ampliamento delle opportunità e potenzialità della scuola dell’infanzia nella formazione dei bambini/e si suggeriscono percorsi formativi e soprattutto scambi culturali per conoscere e condividere credenze e pratiche.
... Infants who detect affordances for spanning gaps in an experienced sitting posture plunge headfirst into impossibly wide gaps when tested moments later in a novice crawling posture (Adolph, 2000). Experienced cruisers who accurately gauge affordances for cruising across gaps in a handrail attempt to cruise into impossibly wide gaps in the floor (Adolph, Berger, & Leo, 2011). And learning is no faster for the next skill in development. ...
Article
The ecological approach is a framework for studying the behavior of animals in their environments. My version of an ecological approach focuses on learning in the context of development. I argue that the most important thing animals learn is behavioral flexibility. They must acquire the ability to flexibly guide their behavior from moment to moment in the midst of developmental changes in their bodies, brains, skills, and environments. They must select, modify, and create behaviors appropriate to the current situation. In essence, animals must learn how to learn. I describe the central concepts and empirical strategies for studying learning in development and use examples of infants coping with novel tasks to give a flavor of what researchers know and still must discover about the functions and processes of learning (to learn) in (not and) development.
... Yet internal factors, such as what parents know and believe about emotions can also impact children's development (Castro, Halberstadt, Lozada, & Craig, 2015;Gottman, Katz, & Hooven, 1996). Further, given the primacy of the body in early development (Adolph, Berger, & Leo, 2011;Kermoian & Campos, 1988), parents' perceptions and articulation of emotion's physiological concomitants could be an important, as yet underappreciated factor impacting how children learn to identify, interpret, and manage their feelings and social lives. In the present study, we developed a measure of parental interoceptive knowledge, i.e., what parents know about how the body feels during different subjective states including emotions. ...
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Interoception, often defined as the perception of internal physiological changes, is implicated in many adult social affective processes, but its effects remain understudied in the context of parental socialization of children’s emotions. We hypothesized that what parents know about the interoceptive concomitants of emotions, or interoceptive knowledge (e.g., “my heart races when excited”), may be especially relevant in emotion socialization and in supporting children’s working models of emotions and the social world. We developed a measure of mothers’ interoceptive knowledge about their own emotions and examined its relation to children’s social affective outcomes relative to other socialization factors, including self- reported parental behaviors, emotion beliefs, and knowledge of emotion relevant situations and nonverbal expressions. To assess these, mothers (N=201) completed structured interviews and questionnaires. A few months later, third-grade teachers rated children’s social skills and emotion regulation observed in the classroom. Results indicated that mothers’ interoceptive knowledge about their own emotions was associated with children’s social affective skills (emotion regulation, social initiative, cooperation, self- control), even after controlling for child gender and ethnicity, family income, maternal stress, and the above maternal socialization factors. Overall, findings suggest that mothers’ interoceptive knowledge may provide an additional, unique pathway by which children acquire social affective competence.
... In a number of studies, Adolph's group has shown that when experienced in a given task young children are able to adapt to the situation at hand (in this case, they were able to judge whether they could cross a gap and also to actually perform this task) (e.g., Adolph, 2000 ). In addition, when tasks differed in terms of the problem space, no transfer was observed between the two situations (cruising over a handrail gap and cruising over a fl oor gap) (e.g., Adolph, Berger, & Leo, 2011 ). These studies offer illustrations of how, through development, the individual learns to adapt their actions to the environment. ...
Chapter
The focus of the chapter is the progression of movement coordination, control and skill in infancy through late childhood, interpreted within Bernstein’s (1967) framework for skill acquisition as the mastery of redundant degrees of freedom. We address three key related issues in motor development from a dynamical systems framework: (a) the number and nature of the degrees of freedom regulated; (b) the pathway of change to the emergent patterns of movement coordination; and (c) the redundancy and variability in solutions to coordination and control – all of which change over time as a function of task constraints in the context of motor learning and development.
... Criteria for participation was being able to sit independently but not yet able to crawl. We chose this age range because the average age of crawling onset is not until around 8 months (Adolph, Vereijken, & Denny, 1998;Adolph, Berger, & Leo, 2011;Berger, Theuring, & Adolph, 2007). Families were recruited via birth announcements published in the local newspaper and recruitment drives held at local libraries and museums in Brooklyn and Staten Island. ...
Article
This study examined the organization of attention in infancy in the context of embodied cognition. Twenty-eight 7-month-old infants, split between Stage 2 and Stage 3 sitters, participated in a modified A-not-B reaching task. Sitting proficiency, experimentally manipulated sitting surface, and whether infants employed compensatory postural control strategies predicted extent of infants’ perseveration. An independent measure of Focused Attention was related to infants’ ability to come up with balance control strategies, which, in turn, minimized infants’ attentional load and facilitated inhibition. These findings suggest a competition of resources between maintaining balance control and engaging in cognitive activity. Investigating balance control, perseverative behaviors, and the relation between the two, revealed that automatization frees attentional resources, not only for the execution of the cognitive task demands per se, but also for recognizing and executing the strategies that facilitate execution of the task.
... In terms of balance control, both typical and amputee infants and children should learn a new perception-action system (Adolph, 2005) in each postural milestone, such as crawling and walking. For each posture, they should maintain their bodies within a dynamic base of support (Adolph et al., 2011). As gait and balance are re-established, reorganization of the motor pattern takes place in order to optimize the functions of the locomotor system (Soares et al., 2009 Such reorganization is however not independent of the prosthetic device that assists the individual in performing physical activities. ...
Article
Background: Children with lower limb loss face gait and balance limitations. Prosthetic rehabilitation is thus aimed at improving functional capacity and mobility throughout the developmental phases of the child amputee. This review of literature was conducted to determine the characteristics of prosthetic gait and balance among children and adolescents with lower-limb amputation or other limb loss. Methods: Both qualitative and quantitative studies were included in this review and data were organized by amputation etiology, age range and level of amputation. Findings: The findings indicated that the structural differences between children with lower-limb amputations and typically developing children lead to functional differences. Significant differences with respect to typically developing children were found in spatiotemporal, kinematic, and kinematic parameters and ground-reaction forces. Children with transtibial amputation place significantly larger load on their intact leg compared to the prosthetic leg during balance tasks. In more complex dynamic balance tests, they generally score lower than their typically developing peers. Interpretation: There is limited literature pertaining to improving physical therapy protocols, especially for different age groups, targeting gait and balance enhancements. Understanding gait and balance patterns of children with lower-limb amputation will benefit the design of prosthetic components and mobility rehabilitation protocols that improve long-term outcomes through adulthood.
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This primer describes research on the development of motor behavior. We focus on infancy when basic action systems are acquired—posture, locomotion, manual actions, and facial actions—and we adopt a developmental systems perspective to understand the causes and consequences of developmental change. Experience facilitates improvements in motor behavior and infants accumulate immense amounts of varied everyday experience with all the basic action systems. At every point in development, perception guides behavior by providing feedback about the results of just prior movements and information about what to do next. Across development, new motor behaviors provide new inputs for perception. Thus, motor development opens up new opportunities for acquiring knowledge and acting on the world, instigating cascades of developmental changes in perceptual, cognitive, and social domains. This article is categorized under: Cognitive Biology > Cognitive Development Psychology > Motor Skill and Performance Neuroscience > Development
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We observed 3 infants at their homes for a month from the time they began to walk, to examine the process of walking initiation. Walking initiation processes were broken down into 4 aspects: (1) postures before walking initiation, (2) hand use for support before walking initiation, (3) stepping strategies, and (4) carrying objects or not. The infants did not always initiate walking with forward steps and no objects in hand. Instead, they often stepped sideways, changed directions by twisting their bodies, shifted their posture, or carried objects. Although various types of walking initiation were observed, each infant seemed to have her/his own preferable types of walking initiation. The results suggested that the initial direction infants faced before walking initiation, and whether furniture was available that could give infants support, constrained how they initiated walking. The development of walking can be understood as a task that emerges in a system that consists of the individual infant and the home environment.
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Neither phenotype nor genotype reliably predicts clinical disease severity or neurodevelopmental outcomes in SCN2A developmental and epileptic encephalopathy. In this study we examined the electroencephalographic (EEG) features of children with SCN2A variants to quantify the range of EEG abnormalities and link EEG biomarkers to developmental outcomes. We retrospectively analyzed data from a cohort of 28 children with SCN2A variants and employed a genetics-based consensus framework to infer the functional characterization of each subject's SCN2A variant. Eleven subjects were predicted to have a gain-of-function variant, and 17 subjects a loss-of-function variant. Overall, variant classifications matched subject phenotypes. 493 EEG recordings from the 28 subjects were analyzed (ages 1 day to 16 years). In addition to the SCN2A recordings, normative data from 1230 children without an epilepsy diagnosis or epileptiform features based on neurologists' review was analyzed (1704 EEG recordings, ages 0 days to 16 years). We detected interictal epileptiform discharges (IEDs) in the SCN2A recordings using Beacon's automated IED detection algorithm. We characterized background spectral features by computing relative power in four frequency bands (delta=1-4Hz, theta=4-8Hz, alpha=8-13Hz, beta=13-30Hz) in recordings from both the SCN2A and control cohorts. Additionally, we determined whether each SCN2A recording was associated with a gross motor developmental delay based on reported attainment of gross motor milestones. We then used mixed effects logistic regression models to estimate the effect of EEG biomarkers on developmental delay. We characterized EEG abnormalities in the background spectral features of the SCN2A cohort compared to the controls and identified differences in EEG signatures between the subjects with gain- and loss-of-function variants. Additionally, we showed that background spectral features are correlated with motor developmental outcome when measured relative to age-matched neurotypical children. Furthermore, we showed that interictal epileptiform activity is correlated with delayed motor development in subjects with gain-of-function variants. Taken together, these findings suggest that EEG biomarkers can be used to identify neurological abnormalities that correlate both with SCN2A variants and measures of development. We demonstrate the potential value of EEG as a disease biomarker, and we highlight the potential of such biomarkers to both guide future invasive genetic therapies and to be used as diagnostic tools.
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Disruptive biological and environmental factors may undermine the development of children's motor and sensorimotor skills. Since the development of cognitive skills, including executive function, is grounded in early motor and sensorimotor experiences, early delays or impairments in motor and sensorimotor processing often trigger dynamic developmental cascades that lead to suboptimal executive function outcomes. The purpose of this perspective paper is to link early differences in motor/sensorimotor processing to the development of executive function in children born preterm or with cerebral palsy. Uncovering such links in clinical populations would improve our understanding of developmental pathways and key motor and sensorimotor skills that are antecedent and foundational for the development of executive function. This knowledge will allow the refinement of early interventions targeting motor and sensorimotor skills with the goal of proactively improving executive function outcomes in at-risk populations.
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This review presents a theoretical account of the development of possibility beliefs in childhood through two developmental pathways, centered around the experience and understanding of our intentional, goal-directed actions. Pathway 1 (Naïve Optimism to Calibrated Realism) can be seen as early as the first year, as increased coordination of action through motor experience leads infants to a graded notion of what is possible and how much effort is required to achieve goals. Infants also incorporate social information into their earliest possibility beliefs, referencing caregivers to guide them in uncertain situations and learning from role models to effectively calibrate effort. Pathway 2 (Naïve Pessimism to Creative Transcendence) emerges from ages 4 to 7. At first, preschoolers correctly distinguish possible and impossible actions but are overly pessimistic about limits on possibility. With age, children use their imaginations to overcome hypothetical limits. This account suggests that realistic beliefs about what we can possibly do are in place in early childhood, preceding later developmental milestones in self-concept, identity, self-efficacy, achievement-orientation, and self-goals. This leaves open questions about mechanisms of change, how possibility beliefs contribute to later self-beliefs, and whether interventions that combine action experience with creative idea generation can increase the sense of the possible in children and adults.
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Several studies have previously investigated the effects of sticky mittens training on reaching and grasping development. However, recent critique casted doubts on the robustness of the motor effect of this training. The current study presents a pre‐registered report that aimed to generalize these effects to Swedish infants. Three‐month‐old infants N = 96, 51 females, mostly White middle class in Uppsala, received daily, parent‐led sticky mittens or observational training for 2 weeks or no training in 2019. Reaching and grasping abilities were assessed before and after training, using motion tracking and a 4‐step reaching task. Sticky mittens training did not facilitate successful reaching. These results indicate that beneficial motor effects of sticky mittens training did not generalize to this sample.
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In most developed nations worldwide, unintentional injury is the leading cause of death for youth 1 through 18 years. Infants are a particularly vulnerable group because motor development enables increased access to hazards, yet they are poorly equipped to assess danger. The current study compared when infants possessed low versus high motor development skills and examined the frequency and type of injury-risk behaviors and parent supervision patterns, as well as modeling how supervision influences injury-risk behaviors across motor development stages and if it does so differentially for boys and girls. Applying a participant-event monitoring method, parents were trained in completing injury-risk behavior diary forms, which they did once the child could move from their seated location on the floor in some way and continued until a month after the child could walk independently. Results revealed few differences between boys and girls in risk behaviors. The overall rate of risk behaviors was greater at high than low motor development stages and there was stability in the rate of individual infant injury-risk behaviors across motor development stages. The same general types of risk behaviors occurred over motor development stages, though about 88% of risk behaviors per se were novel and unfamiliar to parents. Parents supervised boys and girls similarly. However, model testing indicated that greater supervision increased the rate of risk behaviors longitudinally for boys but not girls. Implications for preventing injuries to boys and girls during infancy are discussed.
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The study of motor development has traditionally focused on the timing and sequence of the acquisition of motor skills, such as sitting, crawling, or walking, over the first years of life. Because motor skills are directly observable, motor development serves as a useful exemplar for general principles of development. Current frameworks emphasize motor development in and as a context, such as how change in motor skill interacts with simultaneous change in other developmental domains, how the acquisition of new motor skills creates new opportunities for learning, and how the context in which motor development occurs shapes the course of development. For example, the onset of new motor skills changes the allocation of attentional resources, the quality of infants’ sleep, and available perceptual information. Reciprocally, contexts such as culturally specific parenting practices and individual differences in everyday experiences impact the timing and trajectory of new motor skills.
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Introducción: El gateo representa la primera forma de locomoción autónoma. Se han mencionado las implicaciones de la adquisición del gateo para lograr la marcha independiente y el control motor en el niño, pero son pocos los estudios relacionados con el gateo y sus efectos en el niño de alto riesgo biológico. Por eso se intentó conocer la relación entre la adquisición del gateo y la marcha independiente en una población de niños nacidos de alto riesgo en un programa de seguimiento pediátrico. Material y métodos: Estudio observacional, retrospectivo y descriptivo de una cohorte de niños de alto riesgo que acuden al seguimiento pediátrico, en el cual se revisó el periodo de adquisición del patrón de gateo y la marcha independiente. Resultados: Se integraron cuatro grupos: gateo normal, gateo limítrofe, gateo con retraso y gateo nulo. Se estudió a 558 lactantes; los grupos se integraron con gateo normal, 238 niños; gateo limítrofe, 96 lactantes; retraso en la adquisición del gateo, 207 niños; y gateo nulo, 17 niños. Por género, las niñas gatean mejor, con peso y edad gestacional mayores y predominio en los gateadores. La escala de Bayley señala mejores puntuaciones para los gateadores. En los niños con gateo normal, la marcha independiente se adquirió en el periodo normal a diferencia del grupo con retraso en el gateo en el cual la marcha independiente apareció con retraso. Conclusiones: En este estudio se identificó una relación entre la edad de inicio del gateo con la edad de adquisición de la marcha independiente, con mejor evolución en los niños gateadores.
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New motor skills supply infants with new possibilities for action and have consequences for development in unexpected places. For example, the transition from crawling to walking is accompanied by gains in other abilities-better ways to move, see the world, and engage in social interactions (e.g., Adolph & Tamis-LeMonda, 2014). Do the developmental changes associated with walking extend to the communicative behaviors of caregivers? Thirty infants (14 boys, 16 girls; 93% White, not Hispanic or Latino) and their caregivers (84% held a college degree or higher) were observed during everyday activities at home during the two-month window surrounding the onset of walking (M infant age = 11.98 months, range = 8.74-14.86). Using a cross-domain coding system, we tracked change in the rates of co-occurrence between infants' locomotor actions and caregivers' concurrent language and gesture input. We examined these relations on two timescales-across developmental time, as infants transitioned from crawling to walking, and in real time based on moment-to-moment differences in infant posture. A consistent pattern of results emerged: compared to crawling, bouts of infant walking were more likely to co-occur with caregiver language and gestures that either requested or described movement or provided information about objects. An effect of infants' real-time behavior was also discovered, such that infants were more likely to hear language from their caregivers when they moved while upright compared to prone. Taken together, findings suggest that the emergence of walking reorganizes the infant-caregiver dyad and sets in motion a developmental cascade that shapes the communication caregivers provide. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
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Motor developmental milestones in infancy, such as the transition to self-locomotion, have cascading implications for infants’ social and cognitive development. The current studies aimed to add to this literature by exploring whether and how crawling experience impacts a key social-cognitive milestone achieved in infancy: the development of intentional action understanding. Study 1 used a cross-sectional, age-held-constant design to examine whether locomotor (n = 36) and prelocomotor (n = 36) infants differ in their ability to process a failed intentional reaching action. Study 2 (n = 124) further probed this question by assessing how variability in locomotor infants’ experience maps onto variability in their failed intentional action understanding. Both studies also assessed infants’ tendency to engage in triadic interactions to shed light on whether self-locomotion impacts intentional action understanding directly or indirectly via changes in infants’ interactions with social partners. Altogether, results showed no evidence for the role of self-locomotion in the development of intentional action understanding. Locomotor and prelocomotor infants did not differ in their failed action understanding or levels of triadic engagement (Study 1) and individual differences in days of crawling experience, propensity to crawl during play, and maximum crawling speed failed to predict infants’ intentional action understanding or triadic engagement (Study 2). Explanations for these null findings and alternative influences on the development of intentional action understanding are considered.
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Background: Cycling has gained more attention as an important lifelong physical activity. Learning to cycle independently without assistance is a milestone for most children that requires time and practice to master. Cycling was recently added to the motor development model and so a valid and reliable measure of cycling ability is required to allow accurate assessment of the skill. Cycling has many health benefits along with being a commonly reported physical activity globally and therefore is an important skill to promote in early childhood and throughout life. To date, there are no measurement tools examining the developmental process to independent cycling in the early childhood years. The current study aimed to develop and assess the inter-rater and test-retest reliability of the ‘KIM Cycling Scale’. Methods: Development of the scale occurred in four phases: (1) development of criteria and stages, which used observation of children when learning to cycle and expert panels to develop the initial developmental stages, (2) review of instructions and criteria and pilot inter-rater and test-retest reliability, to ensure that the scale could be used as a standalone scale without requiring further instructions (3) cycling intervention, which allowed assessment of the developmental nature of children along the scale as they learn to cycle independently and to assess typical and alternate routes to independent cycling and (4) inter-rater and test-retest reliability. Results: Ninety children took part in phase 1, thirty-six children took part in phase 2, seventy-four children took part in phase 3 and one hundred and forty-nine children took part in phase 4. All three hundred and forty-nine children were between 2 and 6 years. The developed scale included eight stages in total. The scale was found to have excellent inter-rater reliability (ICC = 0.97, 95% CI = 0.96–0.98) and good to excellent test-retest reliability [(ICC = 0.91, 95% CI = 0.87–0.94) & (ICC = 0.90, 95% CI = 0.85–0.93)]. Typical routes to independent cycling along the scale were examined and reported as being step-wise on all occasions except one where a two stage jump was as common as the step-wise route. Alternate routes were also reported. Conclusion: The current study developed a reliable measurement tool for assessing children between 2 and 6 years of age on the developmental process to independent cycling. Having a cycling scale will allow teachers and practitioners to assess competence in cycling and moreover, track changes in skill development. Furthermore, parents could also use the scale to better understand and better asses their child’s progression when learning to cycle.
Conference Paper
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Diffuse optical tomography (DOT), a subset of functional near-infrared spectroscopy (fNIRS), is a noninvasive functional imaging modality for studying the human brain in normal and diseased conditions. It measures changes in concentrations of oxygenated hemoglobin (HbO) and deoxygenated hemoglobin (Hb) in the blood vasculature of the brain. In contrast to functional magnetic resonance imaging (fMRI), the gold standard in human brain imaging, DOT offers the advantage of higher temporal resolution, portability, lower cost, multiple contrasts and usability for persons who cannot otherwise utilize MRI-based imaging modalities, including bedridden patients and infants, etc. The goal of the present study was to evaluate performance of a DOT method in studying dynamic patterns of brain activations involving motor control. CW-fNIRS data were acquired in four sessions from a healthy male participant when he performed a motor task in a block-design experiment. Results from experimental data showed pronounced activity in the primary motor cortex (M1), contralateral to the clenching hand. It was further observed that the M1 activity was consistent over four sessions. Furthermore, temporal dynamics of motor activity at each session further revealed well-sequenced activation patterns among M1, premotor cortex (PMC), and supplementary motor area (SMA). Timed ipsilateral motor activity suppression was also observed several seconds after the onset of contralateral M1 activity. More importantly, these temporal dynamics were similarly observed in all four sessions. These preliminary results suggest that the DOT method has the sensitivity, reliability, and spatio-temporal resolutions to study activities originated from the motor cortices. A full-scope evaluation and validation in more participants on the motor system can establish it as a promising neuroimaging tool to study, such as, infants at the risk of cerebral palsy or elders with Parkinson's due to its portability and usability in clinical environments.
Article
Infants’ understanding of the intentional nature of human action develops gradually across the first year of life. A key question is what mechanisms drive changes in this foundational social‐cognitive ability. The current studies explored the hypothesis that triadic interactions in which infants coordinate attention between a social partner and an object of mutual interest promote infants’ developing understanding of others as intentional agents. Infants’ spontaneous tendency to participate in triadic engagement was assessed in a semi‐structured play session with a researcher. Intentional action understanding was assessed by evaluating infants’ ability to visually predict the goal of an intentional reaching action. Study 1 (N = 88) revealed that 8‐9‐month‐olds who displayed more bouts of triadic engagement showed better concurrent reasoning about the goal of an intentional reaching action. Study 2 (N = 114) confirmed these findings using a longitudinal design and demonstrated that infants who displayed more bouts of triadic engagement at 6‐7 months were better at prospectively reasoning about the goal of an intentional reaching action three months later. Cross‐lagged path analyses revealed that intentional action understanding at 6‐7 months did not predict later triadic engagement, suggesting that early triadic engagement supports later intentional action processing and not the other way around. Finally, evidence from both studies revealed the unique contribution of triadic over dyadic forms of engagement. These results highlight the importance of social interaction as a developmental mechanism and suggest that infants enrich their understanding of intentionality through triadic interactions with social partners. This article is protected by copyright. All rights reserved.
Article
The development of sitting changes how much infants are able to explore objects. Infants who can sit with their arms free are likely to explore their environment more effectively than prop sitters, as their hands are free to explore. We sought to quantify how prop sitters differed in the amount of visual and manual exploration of objects from arms‐free sitters. Infants younger than 7 months (n = 31) were recruited at sitting emergence, either prop or arms‐free sitting without the ability to change positions. Infants were grouped into sitting stages at baseline: prop (n = 17) or wobbly/arms‐free (n = 14). Across three visits (baseline, 3 weeks later, 6–8 weeks later), researchers assessed the infants’ total gross motor skill, sitting skill, and object looking and active exploration. Infants’ gross motor and sitting skill was assessed using the Gross Motor Function Measure (GMFM)‐66 total scores and GMFM‐88 sitting dimension scores. While researchers supported infants in sitting, object looking and exploration were assessed using a series of three object exploration tasks and scoring modified slightly from the Early Problem Solving Indicator at each visit. Differences between trajectories of prop and wobbly/arms‐free sitters for the frequencies of two behaviors, looks and explores, were analyzed using longitudinal multilevel modeling. Prop sitters initially explored toys less frequently, but increased their exploration more quickly, than wobbly/arms‐free sitters. Sitting skill predicted minor changes in the development of looking; both stage and skill predicted changes uniquely in the development of exploration. These findings suggest that independent, arms‐free sitting changes how capable infants are of exploring objects visually and manually.
Article
Motor development and psychological development are fundamentally related, but researchers typically consider them separately. In this review, we present four key features of infant motor development and show that motor skill acquisition both requires and reflects basic psychological functions. (a) Motor development is embodied: Opportunities for action depend on the current status of the body. (b) Motor development is embedded: Variations in the environment create and constrain possibilities for action. (c) Motor development is enculturated: Social and cultural influences shape motor behaviors. (d) Motor development is enabling: New motor skills create new opportunities for exploration and learning that instigate cascades of development across diverse psychological domains. For each of these key features, we show that changes in infants' bodies, environments, and experiences entail behavioral flexibility and are thus essential to psychology. Moreover, we suggest that motor development is an ideal model system for the study of psychological development. Expected final online publication date for the Annual Review of Psychology Volume 70 is January 4, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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In this paper we suggest that early gait characteristics may be interpreted as stemming from a lack of postural control. In a review of the literature on early gait development we focus on the parameters which have been considered as indexing postural or balance control. In a second part of the paper we present a longitudinal study of early independent walking. The discussion focusses on a comparison of the developmental trend of several parameters indexing postural and, or, locomotor control. From these results we suggest that learning to walk is a two phase developmental process, and that it is only after a achieving mastering of the postural constraints of the movement that a young walker is able to refine locomotor control.
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Fifteen infants were videotaped weekly, beginning at 6 months, until they began to crawl. At each observation, infants were also videotaped as they reached to midline (to assess hand use preference). Of interest were the relative contributions of head orientation, hand use, and kicking for the development of crawling. During early stages, active orienting of the head to one side while prone was associated with particular patterns of both arm position and leg activity. At later stages, hand preference was associated with the transition from the stage of rocking to that of crawling: Infants rocked during a period when they showed ambilaterality during reaching, and they crawled when there was a strong hand preference. Thus, unimanual reaching promoted falling foward onto one hand and extending with the other. The co-occurrence of orienting, reaching, and kicking under particular postural and muscular constraints may account for the stage-like development of crawling. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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The concept of action is examined, with particular attention to the ontogenetic origin of actions and their developmental course. It is argued that actions constitute dynamic interactions between an organism and the outside world which, by necessity, have to be future-oriented. The upcoming forces and momenta induced by a movement have to be counteracted before they upset the flow of action and the balance of the body. The encounter with the environment needs to be prepared and controlled. It is argued, furthermore, that the developmental origins of actions are actions and that a future-oriented mode of control is a basic property of movement at all ages. Finally, it is argued that actions develop through action. By actively moving, the child learns about properties that change and properties that remain invariant during the execution of a task, about problems that arise when coordinating with the external world, and about information that makes it possible to steer action in a prospective way. This learningconstitutes the foundation of motor skill.
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This study investigated developmental changes in the use of a contact surface during the acquisition of upright posture. Standing infants were longitudinally examined at four developmental epochs: pulling to stand (PS); standing alone (SA); walking onset (WO); and 1.5 months post-walking (PW). The results revealed that as standing experience increased the force applied to the contact surface by the hand and the body sway decreased. Applied force and body sway were consistently related in the anterior-posterior direction (r ≈ 0.65). Temporally, body sway led applied force (≈ 45ms) at the PS, SA, and WO developmental periods. However, at PW, the temporal relationship reversed and applied force led body sway (≈ 140 ms). These results indicate that initially infants use surface contact for mechanical purposes but later for orientation information that affords prospective control of posture.
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Three experiments investigated whether 14- and 15-month-old infants use information for both friction and slant for prospective control of locomotion down slopes. In Experiment 1, high- and low-friction conditions were interleaved on a range of shallow and steep slopes. In Experiment 2, friction conditions were blocked. In Experiment 3, the low-friction surface was visually distinct from the surrounding high-friction surface. In all three experiments, infants could walk down steeper slopes in the high-friction condition than they could in the low-friction condition. Infants detected affordances for walking down slopes in the high-friction condition, but in the low-friction condition, they attempted impossibly slippery slopes and fell repeatedly. In both friction conditions, when infants paused to explore slopes, they were less likely to attempt slopes beyond their ability. Exploration was elicited by visual information for slant (Experiments 1 and 2) or by a visually distinct surface that marked the change in friction (Experiment 3).
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Locomotion—moving the body from place to place—is one of infants' greatest achievements. In addition to conquering gravity, infants must cope with variable and novel constraints on balance and propulsion. At the same time that they are learning to move, changes in infants' bodies, skills, and environments change the biomechanical constraints on movement. Recent work highlights both flexibility and specificity in infants' responses to novel and variable situations, demonstrating that infants are learning to learn as they master locomotion. Within sitting, crawling, cruising, and walking postures, experienced infants adapt their locomotor responses to the current biomechanical constraints on movement. However, what infants have learned about coping with variability and novelty in earlier-developing postures does not transfer to later-developing postures.
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The authors examined the effects of locomotor experience on infants' perceptual judgments in a potentially risky situation--descending steep and shallow slopes--while manipulating social incentives to determine where perceptual judgments are most malleable. Twelve-month-old experienced crawlers and novice walkers were tested on an adjustable sloping walkway as their mothers encouraged and discouraged descent. A psychophysical procedure was used to estimate infants' ability to crawl/walk down slopes, followed by test trials in which mothers encouraged and discouraged infants to crawl/walk down. Both locomotor experience and social incentives affected perceptual judgments. In the encourage condition, crawlers only attempted safe slopes within their abilities, but walkers repeatedly attempted impossibly risky slopes, replicating previous work. The discourage condition showed where judgments are most malleable. When mothers provided negative social incentives, crawlers occasionally avoided safe slopes, and walkers occasionally avoided the most extreme 50 degrees increment, although they attempted to walk on more than half the trials. Findings indicate that both locomotor experience and social incentives play key roles in adaptive responding, but the benefits are specific to the posture that infants use for balance and locomotion.
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This research examined how infants in early stages of walking determine whether a hill is safe or risky for locomotion. A psychophysical staircase procedure provided estimates of infants' physical ability to walk up and down slopes (2 degrees to 36 degrees), and a "go ration" indexed the accuracy of their perceptual judgments. On average, perceptual judgments were scaled to walking ability on slopes. Children walked on safe slopes and balked on risky ones. For ascent, perceptual judgments were related to length of walking experience and walking skill on flat ground. Better walkers were also better perceivers. For descent, judgments neatly mirrored exploratory activity. Better perceivers explored hills more efficiently by hesitating, touching, and testing different positions on hills around the limits of their physical ability.
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The effects of infants' age, body dimensions, and experience on the development of crawling was examined by observing 28 infants longitudinally, from children's first attempts at crawling until they began walking. Although most infants displayed multiple crawling postures en route to walking, development did not adhere to a strict progression of obligatory, discrete stages. In particular, 15 infants crawled on their bellies prior to crawling on hands and knees, but the other 13 infants skipped the belly-crawling period and proceeded directly to crawling on hands and knees. Duration of experience with earlier forms of crawling predicted the speed and efficiency of later, quite different forms of crawling. Most important, infants who had formerly belly crawled were more proficient crawling on hands and knees than infants who had skipped the belly-crawling period. Transfer could not be explained by differences in infants' age or body dimensions alone. Rather, experience using earlier crawling patterns may have exerted beneficial effects on hands-and-knees crawling by shoring up underlying constituents common to all forms of crawling postures.
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To determine the frequency and location of bruises in normal infants and toddlers, and to determine the relationship of age and developmental stage to bruising. Cross-sectional survey. Community primary care pediatric offices. Children younger than 36 months attending well-child care visits. Prospective data collection of demographics, developmental stage, and presence and location of bruises. Any medical condition that causes bruises as well as known or suspected abuse was also recorded. A chi2 test or Fisher exact test was used to determine the significance of differences. Presence and location of bruises as related to age and developmental stage. Bruises were found in 203 (20.9%) of 973 children who had no known medical cause for bruising and in whom abuse was not suspected. Only 2 (0.6%) of 366 children who were younger than 6 months and 8 (1.7%) of 473 children younger than 9 months had any bruises. Bruises were noted in only 11 (2.2%) of 511 children who were not yet walking with support (cruising). However, 17.8% of cruisers and 51.9% of walkers had bruises (P<.001). Mean bruise frequency ranged from 1.3 bruises per injured child among precruisers (range, 1-2 bruises) to 2.4 per injured child among walkers (range, 1-11). The most frequent site of bruises was over the anterior tibia and knee. Bruises on the forehead and upper leg were common among walkers, but bruises on the face and trunk were rare, and bruises on the hands and buttocks were not observed at any age. There were no differences in bruise frequency by sex. African American children were observed to have bruises much less frequently than white children (P<.007). Bruises are rare in normal infants and precruisers and become common among cruisers and walkers. Bruises in infants younger than 9 months and who are not yet beginning to ambulate should lead to consideration of abuse or illness as causative. Bruises in toddlers that are located in atypical areas, such as the trunk, hands, or buttocks, should prompt similar concerns.
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Although boys outshine girls in a range of motor skills, there are no reported gender differences in motor performance during infancy. This study examined gender bias in mothers' expectations about their infants' motor development. Mothers of 11-month-old infants estimated their babies' crawling ability, crawling attempts, and motor decisions in a novel locomotor task-crawling down steep and shallow slopes. Mothers of girls underestimated their performance and mothers of boys overestimated their performance. Mothers' gender bias had no basis in fact. When we tested the infants in the same slope task moments after mothers' provided their ratings, girls and boys showed identical levels of motor performance.
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In 2 experiments the authors demonstrated that adaptive locomotion can involve means-ends problem solving. Sixteen-month-old toddlers crossed bridges of varying widths in the presence or absence of a handrail. Babies attempted wider bridges more often than narrow ones, and attempts on narrow bridges depended on handrail presence. Toddlers had longer latencies, examined the bridge and handrail more closely, and modified their gait when bridges were narrow and/or the handrail was unavailable. Infants who explored the bridge and handrail before stepping onto the bridge and devised alternative bridge-crossing strategies were more likely to cross successfully. Results challenge traditional conceptualizations of tools: Babies used the handrail as a means for augmenting balance and for carrying out an otherwise impossible goal-directed task.
Conference Paper
This research examined how infants in early stages of walking determine whether a hill is safe or risky for locomotion. A psychophysical staircase procedure provided estimates of infants' physical ability to walk up and down slopes (2-degrees to 36-degrees), and a ''go ratio'' indexed the accuracy of their perceptual judgments. On average, perceptual judgments were scaled to walking ability on slopes. Children walked on safe slopes and balked on risky ones. For ascent, perceptual judgments were related to length of walking experience and walking skill on flat ground. Better walkers were also better perceivers. For descent, judgments neatly mirrored exploratory activity. Better perceivers explored hills more efficiently by hesitating, touching, and testing different positions on hills around the limits of their physical ability.
Article
This study was undertaken to determine whether young children, after only a few weeks standing experience, could respond adaptively to the dynamical constraints imposed by different support surfaces. The spontaneous postural motions of young children (13-14 months old) were observed as they stood on surfaces that differed in length, friction, and rigidity. There were no externally imposed perturbations to stance. Children's postural control was remarkably adaptive: There were few falls on any of the surfaces. Moreover, the children showed surface-specific utilization of manual postural control (holding onto wooden poles), suggesting that manual control is an adaptive strategy for postural control. Finally, kinematic analysis suggested that, in some instances, children were able to employ independent control of the hips, contrary to previous models which had suggested that hip motions could not be controlled before the age of 3 years. Small, slow hip movements useful in controlling spontaneous sway (unperturbed stance) may serve as a basis for the development of larger, faster hip movements that are associated with imposed perturbations.
Chapter
A few years ago, Emde, Gaensbauer, and Harmon (1976) highlighted two periods of rapid developmental reorganization in infancy. These periods were characterized by dramatic changes in perceptual, cognitive, and especially emotional functions. The period from 7 to 9 months of age is one of these times of rapid reorganization. It is marked by numerous changes in sensorimotor intelligence, including the beginnings of representation, changes in object permanence, new modes of understanding spatial relationships, more complex forms of imitation, and the beginnings of concept formation. This period also appears to be characterized by a burgeoning of fear: Infants at this age react aversively to separation, strangers, heights, looming stimuli, and various unfamiliar toys and objects (Scarr & Salapatek, 1970). The inverse of fear— security—also begins to be clearly evident. The child becomes capable of using the attachment figure as a “haven of safety” and as a “secure base for exploration” (Ainsworth, 1973; Bowlby, 1969). The important changes taking place in the attachment relationship herald major changes in other social contexts as well, including peer and sibling relationships and sociability to strangers (Campos, Barrett, Lamb, Goldsmith, & Stenberg, 1983).
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Locomotion - moving the body from place to place - is one of infants' greatest achievements. In addition to conquering gravity, infants must cope with variable and novel constraints on balance and propulsion. At the same time that they are learning to move, changes in infants' bodies, skills, and environments change the biomechanical constraints on movement. Recent work highlights both flexibility and specificity in infants' responses to novel and variable situations, demonstrating that infants are learning to learn as they master locomotion. Within sitting, crawling, cruising, and walking postures, experienced infants adapt their locomotor responses to the current biomechanical constraints on movement. However, what infants have learned about coping with variability and novelty in earlier-developing postures does not transfer to later-developing postures.
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A short-term longitudinal study was conducted to assess changes in the patterning of the limbs during infants' transition to hands-and-knees crawling Six infants were studied using observational and kinematic assessment techniques The results revealed that all 6 infants converged on the same diagonal interlimb pattern for locomoting shortly after developing sufficient muscle strength to support their abdomens above the support surface This finding is significant because forward prone progression could be accomplished using any number of interlimb patterns (e g, moving one limb at a time), yet a diagonal pattern is the most flexible and dynamically efficient The process by which this behavioral pattern emerges appears consistent with recent developmental theories suggesting that new responses are selected to optimize performance following periods of increased variability induced by changing organismic or environmental conditions
Article
Objectives To determine the frequency and location of bruises in normal infants and toddlers, and to determine the relationship of age and developmental stage to bruising.Design Cross-sectional survey.Setting Community primary care pediatric offices.Subjects Children younger than 36 months attending well-child care visits.Methods Prospective data collection of demographics, developmental stage, and presence and location of bruises. Any medical condition that causes bruises as well as known or suspected abuse was also recorded. A χ2 test or Fisher exact test was used to determine the significance of differences.Main Outcome Measures Presence and location of bruises as related to age and developmental stage.Results Bruises were found in 203 (20.9%) of 973 children who had no known medical cause for bruising and in whom abuse was not suspected. Only 2 (0.6%) of 366 children who were younger than 6 months and 8 (1.7%) of 473 children younger than 9 months had any bruises. Bruises were noted in only 11 (2.2%) of 511 children who were not yet walking with support (cruising). However, 17.8% of cruisers and 51.9% of walkers had bruises (P<.001). Mean bruise frequency ranged from 1.3 bruises per injured child among precruisers (range, 1-2 bruises) to 2.4 per injured child among walkers (range, 1-11). The most frequent site of bruises was over the anterior tibia and knee. Bruises on the forehead and upper leg were common among walkers, but bruises on the face and trunk were rare, and bruises on the hands and buttocks were not observed at any age. There were no differences in bruise frequency by sex. African American children were observed to have bruises much less frequently than white children (P<.007).Conclusions Bruises are rare in normal infants and precruisers and become common among cruisers and walkers. Bruises in infants younger than 9 months and who are not yet beginning to ambulate should lead to consideration of abuse or illness as causative. Bruises in toddlers that are located in atypical areas, such as the trunk, hands, or buttocks, should prompt similar concerns.
Article
Infants master crawling and walking in an environment filled with varied and unfamiliar surfaces. At the same time, infants' bodies and skills continually change. The changing demands of everyday locomotion require infants to adapt locomotion to the properties of the terrain and to their own physical abilities. This Monograph examines how infants acquire adaptive locomotion in a novel task-going up and down slopes. Infants were tested longitudinally from their first week of crawling until several weeks after they began walking. Everyday locomotor experience played a central role in adaptive responding. Over weeks of crawling, infants' judgments became increasingly accurate, and exploration became increasingly efficient. There was no transfer over the transition from crawling to walking. Instead, infants learned, all over again, how to cope with slopes from an upright position. Findings indicate that learning generalized from everyday experience traveling over flat surfaces at home but that learning was specific to infants' typical method of locomotion and vantage point. Moreover, learning was not the result of simple associations between a particular locomotor response and a particular slope. Rather, infants learned to gauge their abilities on-line as they encountered each hill at the start of the trial. Change in locomotor responses and exploratory movements revealed a process of differentiation and selection spurred by changes in infants' everyday experience, body dimensions, and locomotor proficiency on flat ground.
Article
It has been hypothesized that animals go through phases in behavioral development where movements initially show excessive degrees of freedom, then are simplified with skill mastery, and are re-elaborated with learning to reach the same goal through variable means. To determine if this is true for stages seen in children's balance development we explored changes in balance abilities in infants (7–15 months) during the transition to independent stance. With the emergence of ‘pull to stand’ behavior infants showed excessive movement at the ankle, knee and hip joint and postural muscle responses were disorganized, with delayed and variable onset latencies. Response organization improved with experience in dependent stance. At the onset of independent stance, response patterns again showed increased variability. However, with increased experience and the onset of independent walking the response organization became consistent and latencies were shortened to more mature levels. With continued experience children began to experiment with alternate strategies of balance adjustments.
Article
The purpose of this study has been to demonstrate successive changes in neuromuscular activities which culminate in the development of a mature, integrated, human gait. A total of 3,387 observations were made upon a group of 82 infants ranging in age from birth to 5 years. On the basis of these observations it was possible to select criteria which differentiated seven fairly distinct phases in the development of erect locomotion. Once the criteria were defined, it was possible to rate the accumulated observations in accordance with the phase representative of the mode of behavior described. These ratings reduced the data to a symbolic system so that curves showing the trend and duration of each phase could be obtained. Similar curves were presented showing the development of erect progression as manifested by five individual children, two of whom were identical twin boys. In addition, calculations were made which indicate the rate of development in this activity as represented by the group and the individuals. In determining the criteria of each phase, it was recognized that certain changes in overt behavior reflect reorganization of the neural centers involved in the activity. On the basis of cytologic studies cited, the analysis embarked with the basic assumption that behavior characteristic of the newborn infant is controlled at a nuclear or subcortical level. Further analysis concerned those qualities of overt behavior which reflected (a) an inhibitory influence from the cortex upon the functioning of infracortical centers, (b) the onset of cortical participation in activating or conducting a particular aspect of the behavior pattern, and (c) the expansion and integration of various cortically controlled movements which are essential to an integrated bipedal gait. Similarly analyses were made of the changing configurations in neuromuscular movements which lead to the assumption of an erect posture. Criteria were proposed for the differentiation of seven significant phases. Because of the relative sparseness of the observations on this activity the data were not given the critical analysis as were those concerning the development of erect locomotion. However, the general trend of development is indicated, and the qualities of overt behavior which reflect neural reorganization are described. It was pointed out that changes in anatomical dimensions, as well as neural reorganization, may be factors affecting the overt expression of neuromuscular performances. In various motor performances the onset of cortical functioning appears to progress in a cephalocaudal direction. The criteria proposed in the selection of the several phases of each activity have embodied those features which indicate the fundamental course of development without regard for individual peculiarities. On the other hand, individual variations may signify temporary differences as to the order in which various aspects of the function advance. For example, some infants may, at a given time, show greater advancement in the aspect of progression while others manifest control over the equilibratory in advance of progressive mechanisms. Such variations are relatively unimportant since all aspects are finally interconnected for the performance of an integrated act. However, there is reason to believe that variations as to the manner or order in which different aspects of neuromuscular development gain ascendency may provide a means for the study of predominating or identifying qualities in individuals.
Article
Cruising represents an important transition from quadrupedal to bipedal locomotion. While cruising, infants discover ways to control their trunks in upright. We predicted that the movement patterns infants demonstrated when learning to control the trunk in order to cruise and walk independently would reflect the process Bernstein [cf. N.B. Bernstein, The Coordination and Regulation of Movements, Pergamon Press, Oxford, England, 1967] proposed for adults' skill acquisition. In addition, we expected that infants would demonstrate a precursor poorly controlled exploratory phase, what we termed the “wobble phase”. We examined longitudinal changes in movement control of the thorax and pelvis from the onset of cruising through the onset of walking. Our findings suggest that learning to cruise involves an initial wobble phase followed by a gradual reduction in the wobble, or number of movement corrections. Finally a relative plateau period of control emerged with sporadic variability in the movement patterns of the thorax and pelvis. We suggest that the fact that infants did not show a phase in which they froze degrees of freedom was due to a lack of the minimum level of control one needs in order to do this. By the end of cruising, although functionally quite skillful, infants continued to demonstrate multiple and varied patterns of control. Infants limit the degrees of freedom just enough to successfully accomplish the task. We argue that variability remains due to: the minimal negative consequences of trunk inconsistency in this context given the available arm support; the trunk acts as a flexible interface for the, as yet, unstable coupling between the arms and legs; and the low number of constraints in relation to the multiple solutions that the task affords. Despite of the remaining variability, it appears that the control of the trunk acquired during cruising enables infants to shift into walking independently.
Article
Six chapters are included: structural foundations of behavior, neonatal behavior, development of neuromotor activities, some aspects of early sensory development, individual development, maturation and learning. In the first chapter, exact principles and experimental findings are listed, and a list of assumptions which provide a theoretical framework are stated. Throughout the book the author correlates as closely as possible the behavioral data with the neurological data now available. Most space is devoted to neuromotor activities, and diagrams, tables, and graphs are used wherever possible. In discussing maturation and learning, educational hints are systematically presented as conclusions from experimental studies. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
A study of growth during the first two years. The data were secured from periodic and comparative examinations of individual infants in a guidance nursery. Part I deals with the mechanics of observation. A specially constructed 16-mesh wire screen permits an observer to observe the entire field of the nursery without being seen by the infants. An interchangeable and interadjustable observation compartment permits of the observation of the more rangy and freer body adaptations of the child. A clinical crib, adjustable in many directions, is especially adapted to the needs of photographic research. A complicated observational dome makes possible the concealment from the view of the infant of the photographic operator, as well as standardized and flexible control of the cameras, of which two are still and two cinema. Specimens of the photographs obtained are shown; among these are several pairs of simultaneous photographs. The comparative method is employed in clinical observation. Part II states that inherent maturation factors determine the tempo of development. Hemihypertrophy is discussed as having a bearing on embryonic conditions which determine normal bodily and mental development. The developmental consequences of twinning are discussed. A drawing developmental index is considered useful as an indicator of the degree of psychomotor development. Motor theories of mental development are criticized. Part III which deals with the significance of infancy, is semi-historical and speculative and presents numerous miscellaneous facts. It raises the question of heredity vs. environment, and deals with concepts of growth potency and maturation. The last few chapters amplify the idea that growth yields to measurement and prediction. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Social behaviors, such as joint attention, social referencing, and protocommunicative acts, which emerge toward the end of the 1st year of life, have commonly been taken as evidence of considerable social understanding, even an "implicit" theory of mind. This paper argues against the "commonsense view" of joint attention and other social behaviors emerging toward the end of the 1st year of life in infants and suggests that the phenomena are entirely compatible with an account which does not attribute to the infant an understanding that others engage in psychological relations with objects or that self and others are equivalent in their potential for engaging in such psychological relations. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Work with infants on the “visual cliff” links avoidance of drop-offs to experience with self-produced locomotion. Adolph's (2002) research on infants' perception of slope and gap traversability suggests that learning to avoid falling down is highly specific to the postural context in which it occurs. Infants, for example, who have learned to avoid crossing risky slopes while crawling must learn anew such avoidance when they start walking. Do newly walking infants avoid crossing the drop-off of the visual cliff? Twenty prewalking but experienced crawling infants were compared with 20 similarly aged newly walking infants on their reactions to the visual cliff. Newly walking infants avoided moving onto the cliff's deep side even more consistently than did the prewalking crawlers. Thus, in the context of drop-offs in visual texture, our results show that once avoidance of drop-offs is established under conditions of crawling, it is developmentally maintained once infants begin walking.
Article
Early detour ability may not generalize immediately across similar problems in different perception–action systems, but instead may reveal a pattern of developmental onset that is more domain-specific. To investigate this possibility, we examined how 10-month-old (n = 24) and 12-month-old (n = 24) infants performed detours via different action modes and around barriers that differed in transparency. Infants made reaching and locomotor detours to retrieve an object located behind either an upright transparent barrier or an upright transparent barrier overlaid with a grid pattern. The results indicated that infants were more likely to make reaching than locomotor detours and explored the transparent and grid barriers differently. Additionally, younger infants more often attempted to contact the object through the entirely transparent barrier than did older infants, especially when making a reaching detour. The results suggest that during detour development, infants learn to coordinate relevant perceptual information with emerging actions.
Article
The effects of infants' age, body dimensions, and experience on the development of crawling was examined by observing 28 infants longitudinally, from children's first attempts at crawling until they began walking. Although most infants displayed multiple crawling postures en route to walking, development did not adhere to a strict progression of obligatory, discrete stages. In particular, 15 infants crawled on their bellies prior to crawling on hands and knees, but the other 13 infants skipped the belly-crawling period and proceeded directly to crawling on hands and knees. Duration of experience with earlier forms of crawling predicted the speed and efficiency of later, quite different forms of crawling. Most important, infants who had formerly belly crawled were more proficient crawling on hands and knees than infants who had skipped the belly-crawling period. Transfer could not be explained by differences in infants' age or body dimensions alone. Rather, experience using earlier crawling patterns may have exerted beneficial effects on hands-and-knees crawling by shoring up underlying constituents common to all forms of crawling postures.
Article
The development of posture and locomotion provides a valuable window for understanding the ontogeny of perception-action relations. In this study, 13 infants were examined cross-sectionally while standing quietly either hands-free or while lightly touching a contact surface. Mean sway amplitude results indicate that infants use light touch for sway attenuation (≈28–40%) as has been seen previously with adults (Jeka & Lackner, 1994). Additionally, while using the contact surface, movement patterns of the head and trunk show reduced temporal coordination (≈25–40%), as well as increased temporal variability, as compared to no touch conditions. These findings are discussed with regard to the ontogeny of perception-action relations, with the overall conclusion that infants use somatosensory information in an exploratory manner to aid in the development of an accurate internal model of upright postural control.
Article
This paper discusses some of the problems associated with observational data analysis for complex domains, and introduces the term "exploratory sequential data analysis" (ESDA) to describe the different kinds of observational data analysis currently being performed in many areas of the behavioral and social sciences. The development and functionality of a software tool—MacSHAPA—for certain kinds of ESDA is described. MacSHAPA is designed to bring investigators into closer contact with their data and to help them achieve greater research productivity and quality. MacSHAPA allows investigators to see their data in various ways, to enter it, edit it and encode it, and to carry out statistical analyses and make reports. MacSHAPA's relation to other ESDA software tools is indicated throughout the paper.
Article
Using a means-means-ends problem-solving task, this study examined whether 16-month-old walking infants (N = 28) took into account the width of a bridge as a means for crossing a precipice and the location of a handrail as a means for augmenting balance on a narrow bridge. Infants were encouraged to cross from one platform to another over narrow and wide bridges located at various distances from a wooden handrail. Infants attempted to walk over the wide bridge more often than the narrow one and when the handrail was within reach. Infants demonstrated parallel problem solving by modifying exploratory behaviors and bridge-crossing strategies that simultaneously accounted for the spatial and functional relations between body and bridge, body and handrail, and bridge and handrail.
Article
Thesis (Ph. D.)--University of Minnesota, 1980. Includes bibliographical references (leaves 92-98).
Article
When prelocomotor infants are supported on a motorized treadmill, they perform well-coordinated, alternating stepping movements that are kinematically similar to upright bipedal locomotion. This behavior appeared to be a component of independent walking that could not be recognized without the facilitating context of the treadmill. To understand the ontogenetic origins of treadmill stepping and its relation to later locomotion, we conducted a longitudinal study using an experimental strategy explicitly derived from dynamic systems theory. Dynamic systems theory postulates that new forms in behavior emerge from the cooperative interactions of multiple components within a task context. This approach focuses on the transitions, often nonlinear, where one preferred mode of behavior is replaced by a new form. Specific predictions about these transitions help uncover the processes by which development proceeds. Chapters II, III, and IV introduce dynamic principles of pattern formation and their application to development. In our application of these principles, we tested nine normal infants twice each month beginning from month 1 in a task where the treadmill speed was gradually scaled up and in an additional condition where each leg was driven by the treadmill at a different speed. Kinematic variables were derived from computerized movement analysis equipment and videotaped records. We also collected a number of anthropometric measurements, Bayley motor scores, and a behavioral mood scale for each month. Several infants stepped on the treadmill in their first month, but in all infants performance showed a rapidly rising slope from month 3 to month 6. Infants also showed corresponding improvement in adjustments to speed and relative coordination between the legs. In dynamic terminology, we found evidence that alternating stepping on the treadmill became an increasingly stable attractor during the middle months of the first year. Dynamic predictions that transitions would be characterized by increased variability and sensitivity to perturbation were borne out. Identifying the transitions enabled us to suggest a control parameter or variable moving the system into the stable response to the treadmill. This appeared to be the waning of flexor dominance in the legs during posture and movement that allowed the leg to be stretched back on the treadmill and so elicited the bilaterally alternating response. Further studies are needed to test this hypothesis. This dynamic analysis confirmed earlier suggestions that skill in general, and locomotion in particular, develops from the confluence of many participating elements and showed how emergent forms may result from changes in nonspecific components. A dynamic approach may be useful for understanding ontogenetic processes in other domains as well.
Article
The Denver Developmental Screening Test (DDST) was devised to provide a simple method of screening for evidences of slow development in infants and preschool children. The test covers four functions: gross motor, language, fine motor-adaptive, and personal-social. It has been standardized on 1,036 presumably normal children (two weeks to six years of age) whose families reflect the occupational and ethnic characteristics of the population of Denver.
Article
3 longitudinal studies were conducted to examine the generalization of detour ability across motor responses and barrier types and the relationship between the development of object permanence and detour ability. In Experiment 1, 12 8-month-olds were tested every 3 weeks for 4 months on 4 different detour problems and Stage 4 and 6 object permanence tasks. In the detour problems, infants had to reach or move around a transparent or opaque barrier to obtain an object. The results indicated that infants made reaching detours before corresponding locomotor ones and generally made detours around opaque barriers before transparent ones. Infants also solved the Stage 4 task before the detour problems but failed to solve the Stage 6 task before testing ended. The results of Experiments 2 and 3 suggested that the difference in reaching and locomotor detour performance was not an artifact of barrier length or the infant's position relative to the barrier. The overall results are discussed in relation to issues of developmental synchrony and Piaget's theory of infant spatial development.
Article
The production of pointing and other gestures (e.g. reaching or indicative gestures) by 47 infants aged 1;0 to 1;6 was investigated in two experiments contrasting declarative-referential vs. imperative-instrumental conditions of communication. A further group of seven infants aged 0;10 was examined in order to highlight pre-pointing transitional phenomena. Data analyses concerned gestures and associated vocalizations and visual checking with a social partner. Results show that gestures are produced differentially in the experimental conditions: while reaching is only produced in imperative-instrumental contexts, pointing is characteristic of declarative-referential contexts. The pattern of visual checking with the social partner also differentiates gestures; moreover, it shows developmental changes in the case of pointing. Results suggest that pointing relies on some awareness of 'psychological' processes (e.g. attention and sharing) in the other and the self, and that it is this which may account for the specific relevance of pointing for language development.
Article
Nine-month-old infants were tested at the precipice of safe and risky gaps in the surface of support. Their reaching and avoidance responses were compared in two postures, an experienced sitting posture and a less familiar crawling posture. The babies avoided reaching over risky gaps in the sitting posture but fell into risky gaps while attempting to reach in the crawling posture. This dissociation between developmental changes in posture suggests that (a) each postural milestone represents a different, modularly organized control system and (b) infants' adaptive avoidance responses are based on information about their postural stability relative to the gap size. Moreover, the results belie previous accounts suggesting that avoidance of a disparity in depth of the ground surface depends on general knowledge such as fear of heights, associations between depth information and falling, or knowledge that the body cannot be supported in empty space.
Article
NOTES AND DISCUSSIONS THE STAIRCASE-METHOD IN PSYCHOPHYSICS A psychophysical method variously referred to as the method of up and downs, 1 the Bekesy audiometric method, 2 or the staircase-method, has come into extensive use in the last few years. The method has several advantages over other more commonly used techniques but it also has some disadvantages. This paper will illustrate the use of the method, will discuss its relative merits and demerits, and will describe a modification which overcomes certain of the disadvantages of the method. The staircase-method is best described by illustrating its use with a specific prob- lem. Suppose the problem is to determine S's absolute, intensive threshold for the sound of a click. The first stimulus that E delivers is a click of some arbitrary intensity. S responds either that he did or did not hear it. If S says 'yes' (he did hear it), the next stimulus is made less intense, and if S says 'no,' the second stimulus is made more intense. If S responds 'yes' to the second stimulus, the third is made less intense, and if he says 'no,' it is made more intense. This procedure is simply continued until some predetermined criterion or 'number of trials' is reached. The results of a series of 30 trials are shown in Fig. 1. The results may be recorded directly on graph-paper; doing so helps E keep the procedure straight. There are a number of ways of determining the intensive value that represents the threshold. The simplest is to compute the mean of the values of a given num- ber of stimuli delivered after the series has reached its final level. This requires an arbitrary decision about when the final level has been reached. The technique, which avoids this difficulty and yields a 50% value, is simply to determine the stimulus above which 50% of the responses are 'yes,'-i.e. in Fig. 1 between 61 and 62 db. Statistical treatment of the results has been discussed by Dixon and Massey, who describe the techniques for determining the means, standard deviations, standard errors, etc., for this type of data.3 The treatments assume, however, that the response to each stimulus is independent of the preceding stimuli and pre- ceding responses. This assumption holds for the examples analyzed, but there is evidence that the assumption does not always hold for human Ss in psychophysical experiments.• The development of techn.iques that take the existing inter-actions into account has not as yet been achieved. W. J. Dixon and F. J. Massey, lnt,.oduction lo Statistical Analysis, 1957, 279· •Georg von Bekesy, A new audiometer, A'la 010-/a,.yngol., 35, 1947, 411-422. •Dixon and Massey, op. cit., 286. • W. S. Verplanck, G. H. Collier, and J. W. Cotton, Nonindependence of succes- sive responses in measurement of the visual threshold, /. exp. Psycho/., 42, 1952, 273-282; Verplanck and Cotton, The dependence of frequencies of seeing on pro- cedural variables: J. Direction and length of series of intensity-ordered stimuli, /. gen. Psycho/., 53, 1955, 37-47; V. L. Senders, Further analysis of response se- quences in the setting of a psychophysical experiment, this JOURNAL, 66, 1 953, 215-229; R. S. Woodworth and Harold Schlosberg, Experimental Psychology, 1954,