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Quantification of Natural Multimodal Interaction Capacity
Abstract
In multimodal interaction, information is presented to users through multiple channels, e.g., sight, sound, touch, smell, and taste. Too much information delivered in a short time, however, may result in information overload that overflows people’s information processing capacity. We summarized the methods of quantifying the capacity by categorizing them into the span of storage or the speed of processing. The span of storage mainly includes short-term memory and working memory capacity and multiple object tracking capacity. Working memory is required in many intellectual functions, and its capacity could be tested with change detection tasks, self-ordered tasks, and complex span tasks. Whether different modalities have separate capacities, whether objects or features are stored, and whether the capacity works as discrete slots or a continuous resource pool were discussed. The speed of processing could be calculated as the information transfer rate with the stimuli and responses matrix; Entropy is used for more complex stimuli such as languages. The relative capacity of multitasking, which is often incorporated in multimodal interaction, could be calculated with the capacity coefficient. The application of these methods to the non-traditional modalities in human-computer interaction, e.g., touch, smell, and taste, was discussed.
Taste research has been hampered by technical difficulties, mostly because liquid taste stimuli are difficult to control in terms of timing and application area. Exact stimulus control requires a gustometer, but the existing devices are either not well-documented or rather inflexible. We designed a gustometer based on a computer-controlled, modular pump system, which can be extended via additional hardware modules—for example, for heating of the stimuli or sending and receiving triggers. All components are available for purchase “off the shelf.” The pumps deliver liquids through plastic tubing and can be connected to commercially available or custom-made mouthpieces. We determined the temporal precision of the device. Onset delays showed minuscule variation within pumps (SD < 3 ms) and small differences between pumps (< 4.5 ms). The rise time was less than 2 ms (SD < 2 ms), and the dosage volume bias was only 2%. To test whether hemitongues could be stimulated independently, we conducted a behavioral experiment. A total of 18 participants received tasteless stimuli to the left, right, or both sides of the tongue. The side of stimulation was correctly identified on 91% of trials, indicating that the setup is suitable for lateralized stimulation. Electroencephalographic responses to water and salty stimuli were recorded from two participants; the stimulation successfully evoked event-related responses, demonstrating the suitability of the device for use in electrophysiological investigations. We provide a Python-based open-source software package and a Web interface to easily operate the system. We thereby hope to facilitate access to state-of-the-art taste research methods and to increase reproducibility across laboratories.
When we are babies we put anything and everything in our mouths, from Lego to crayons. As we grow older we increasingly rely on our other senses to explore our surroundings and objects in the world. When interacting with technology, we mainly rely on our senses of vision, touch, and hearing, and the sense of taste becomes reduced to the context of eating and food experiences. In this paper, we build on initial efforts to enhance gaming experiences through gustatory stimuli. We introduce TasteBud, a gustatory gaming interface that we integrated with the classic Minesweeper game. We first describe the details on the hardware and software design for the taste stimulation and then present initial findings from a user study. We discuss how taste has the potential to transform gaming experiences through systematically exploiting the experiences individual gustatory stimuli (e.g., sweet, bitter, sour) can elicit.
The quick and reliable detection and identification of a tastant in the mouth regulate nutrient uptake and toxin expulsion. Consistent with the pivotal role of the gustatory system, taste category information (e.g., sweet, salty) is represented during the earliest phase of the taste-evoked cortical response (Crouzet et al., 2015), and different tastes are perceived and responded to within only a few hundred milliseconds, in rodents (Perez et al., 2013) and humans (Bujas, 1935). Currently, it is unknown whether taste detection and discrimination are sequential or parallel processes, i.e., whether you know what it is as soon as you taste it. To investigate the sequence of processing steps involved in taste perceptual decisions, participants tasted sour, salty, bitter, and sweet solutions and performed a taste-detection and a taste-discrimination task. We measured response times (RTs) and 64-channel scalp electrophysiological recordings and tested the link between the timing of behavioral decisions and the timing of neural taste representations determined with multivariate pattern analyses. Irrespective of taste and task, neural decoding onset and behavioral RTs were strongly related, demonstrating that differences between taste judgments are reflected early during chemosensory encoding. Neural and behavioral detection times were faster for the iso-hedonic salty and sour tastes than their discrimination time. No such latency difference was observed for sweet and bitter, which differ hedonically. Together, these results indicate that the human gustatory system detects a taste faster than it discriminates between tastes, yet hedonic computations may run in parallel (Perez et al., 2013) and facilitate taste identification.
Cars provide drivers with task-related information (e.g. "Fill gas") mainly using visual and auditory stimuli. However, those stimuli may distract or overwhelm the driver, causing unnecessary stress. Here, we propose olfactory stimulation as a novel feedback modality to support the perception of visual notifications, reducing the visual demand of the driver. Based on previous research, we explore the application of the scents of lavender, peppermint, and lemon to convey three driving-relevant messages (i.e. "Slow down", "Short inter-vehicle distance", "Lane departure"). Our paper is the first to demonstrate the application of olfactory conditioning in the context of driving and to explore how multiple olfactory notifications change the driving behaviour. Our findings demonstrate that olfactory notifications are perceived as less distracting, more comfortable, and more helpful than visual notifications. Drivers also make less driving mistakes when exposed to olfactory notifications. We discuss how these findings inform the design of future in-car user interfaces.
Working memory can be divided into separate subsystems for verbal and visual information. Although the verbal system has been well characterized, the storage capacity of visual working memory has not yet been established for simple features or for conjunctions of features. The authors demonstrate that it is possible to retain information about only 3-4 colors or orientations in visual working memory at one time. Observers are also able to retain both the color and the orientation of 3-4 objects, indicating that visual working memory stores integrated objects rather than individual features. Indeed, objects defined by a conjunction of four features can be retained in working memory just as well as single-feature objects, allowing many individual features to be retained when distributed across a small number of objects. Thus, the capacity of visual working memory must be understood in terms of integrated objects rather than individual features.
The past decade has witnessed a consolidation and refinement of the extraordinary progress made in taste research. This Review describes recent advances in our understanding of taste receptors, taste buds, and the connections between taste buds and sensory afferent fibres. The article discusses new findings regarding the cellular mechanisms for detecting tastes, new data on the transmitters involved in taste processing and new studies that address longstanding arguments about taste coding.
In the last decade, we have witnessed a drastic change in the form factor of audio and vision technologies, from heavy and grounded machines to lightweight devices that naturally fit our bodies. However, only recently, haptic systems have started to be designed with wearability in mind. The wearability of haptic systems enables novel forms of communication, cooperation, and integration between humans and machines. Wearable haptic interfaces are capable of communicating with the human wearers during their interaction with the environment they share, in a natural and yet private way. This paper presents a taxonomy and review of wearable haptic systems for the fingertip and the hand, focusing on those systems directly addressing wearability challenges. The paper also discusses the main technological and design challenges for the development of wearable haptic interfaces, and it reports on the future perspectives of the field. Finally, the paper includes two tables summarizing the characteristics and features of the most representative wearable haptic systems for the fingertip and the hand.
This paper describes a discussion on the method and the status of a statistical theory of sound and vibration, called statistical energy analysis (SEA). SEA is a simple theory of sound and vibration in elastic structures that applies when the vibrational energy is diffusely distributed. We show that SEA is a thermodynamical theory of sound and vibration, based on a law of exchange of energy analogous to the Clausius principle. We further investigate the notion of entropy in this context and discuss its meaning.We show that entropy is a measure of information lost in the passage from the classical theory of sound and vibration and SEA, its thermodynamical counterpart. © 2017 The Author(s) Published by the Royal Society. All rights reserved.
The topic of working memory (WM) is ubiquitous in research on cognitive psychology and on individual differences. According to one definition, it is a small amount of information kept in a temporary state of heightened accessibility; it is used in most types of communication and problem solving. Short-term storage has been defined as the passive (i.e., non-attention-based, nonstrategic) component of WM or, alternatively, as a passive store separate from an attention-based WM. Here I note that much confusion has been created by the use by various investigators of many, subtly different definitions of WM and short-term storage. The definitions are sometimes made explicit and sometimes implied. As I explain, the different definitions may have stemmed from the use of a wide variety of techniques to explore WM, along with differences in theoretical orientation. By delineating nine previously used definitions of WM and explaining how additional ones may emerge from combinations of these nine, I hope to improve scientific discourse on WM. The potential advantages of clarity about definitions of WM and short-term storage are illustrated with respect to several ongoing research controversies.
The senses we call upon when interacting with technology are very restricted. We mostly rely on vision and audition, increasingly harnessing touch, whilst taste and smell remain largely underexploited. In spite of our current knowledge about sensory systems and sensory devices, the biggest stumbling block for progress concerns the need for a deeper understanding of people's multisensory experiences in HCI. It is essential to determine what tactile, gustatory, and olfactory experiences we can design for, and how we can meaningfully stimulate such experiences when interacting with technology. Importantly, we need to determine the contribution of the different senses along with their interactions in order to design more effective and engaging digital multisensory experiences. Finally, it is vital to understand what the limitations are that come into play when users need to monitor more than one sense at a time. The aim of this workshop is to deepen and expand the discussion on touch, taste, and smell within the CHI community and promote the relevance of multisensory experience design and research in HCI.
Kristjansson (2015) suggests that standard research methods in the study of visual search should be “reconsidered.” He reiterates a useful warning against treating reaction time x set size functions as simple metrics that can be used to label search tasks as “serial” or “parallel.” However, I argue that he goes too far with a broad attack on the use of slopes in the study of visual search. Used wisely, slopes do provide us with insight into the mechanisms of visual search.
Touch is a powerful vehicle for communication between humans. The way we touch (how) embraces and mediates certain emotions such as anger, joy, fear, or love. While this phenomenon is well explored for human interaction, HCI research is only starting to uncover the fine granularity of sensory stimulation and responses in relation to certain emotions. Within this paper we present the findings from a study exploring the communication of emotions through a haptic system that uses tactile stimulation in mid-air. Here, haptic descriptions for specific emotions (e.g., happy, sad, excited, afraid) were created by one group of users to then be reviewed and validated by two other groups of users. We demonstrate the non-arbitrary mapping between emotions and haptic descriptions across three groups. This points to the huge potential for mediating emotions through mid-air haptics. We discuss specific design implications based on the spatial, directional, and haptic parameters of the created haptic descriptions and illustrate their design potential for HCI based on two design ideas.
Multisensory processes are vital in the perception of our environment. In the evaluation of foodstuff, redundant sensory inputs not only assist the identification of edible and nutritious substances, but also help avoiding the ingestion of possibly hazardous substances. While it is known that the non-chemical senses interact already at early processing levels, it remains unclear whether the visual and olfactory senses exhibit comparable interaction effects. To address this question, we tested whether the perception of congruent bimodal visual-olfactory objects is facilitated compared to unimodal stimulation. We measured response times (RT) and accuracy during speeded object identification. The onset of the visual and olfactory constituents in bimodal trials was physically aligned in the first and perceptually aligned in the second experiment. We tested whether the data favored coactivation or parallel processing consistent with race models. A redundant-signals effect was observed for perceptually aligned redundant stimuli only, i.e., bimodal stimuli were identified faster than either of the unimodal components. Analysis of the RT distributions and accuracy data revealed that these observations could be explained by a race model. More specifically, visual and olfactory channels appeared to be operating in a parallel, positively dependent manner. While these results suggest the absence of early sensory interactions, future studies are needed to substantiate this interpretation.
Visual input is processed in parallel in the early stages of the visual system. Later, object recognition processes are also massively parallel, matching a visual object with a vast array of stored representation. A tight bottleneck in processing lies between these stages. It permits only one or a few visual objects at any one time to be submitted for recognition. That bottleneck limits performance on visual search tasks when an observer looks for one object in a field containing distracting objects. Guided Search is a model of the workings of that bottleneck. It proposes that a limited set of attributes, derived from early vision, can be used to guide the selection of visual objects. The bottleneck and recognition processes are modeled using an asynchronous version of a diffusion process. The current version (Guided Search 4.0) captures a wide range of empirical findings.
Working memory is widely considered to be limited in capacity, holding a fixed, small number of items, such as Miller's 'magical number' seven or Cowan's four. It has recently been proposed that working memory might better be conceptualized as a limited resource that is distributed flexibly among all items to be maintained in memory. According to this view, the quality rather than the quantity of working memory representations determines performance. Here we consider behavioral and emerging neural evidence for this proposal.
The concept of capacity has become increasingly important in discussions of working memory (WM), in so far as most models of WM conceptualize it as a limited-capacity mechanism for maintaining information in an active state, and as capacity estimates from at least one type of WM task-complex span-are valid predictors of real-world cognitive performance. However, the term capacity is also often used in the context of a distinct set of WM tasks, change detection, and may or may not refer to the same cognitive capability. We here develop maximum-likelihood models of capacity from each of these tasks-as well as from a third WM task that places heavy demands on cognitive control, the self-ordered WM task (SOT)-and show that the capacity estimates from change detection and complex span tasks are not correlated with each other, although capacity estimates from change detection tasks do correlate with those from the SOT. Furthermore, exploratory factor analysis confirmed that performance on the SOT and change detection load on the same factor, with performance on our complex span task loading on its own factor. These findings suggest that at least two distinct cognitive capabilities underlie the concept of WM capacity as it applies to each of these three tasks.
Systems factorial technology (SFT) comprises a set of powerful nonparametric models and measures, together with a theory-driven experiment methodology termed the double factorial paradigm (DFP), for assessing the cognitive information-processing mechanisms supporting the processing of multiple sources of information in a given task (Townsend and Nozawa, Journal of Mathematical Psychology 39:321-360, 1995). We provide an overview of the model-based measures of SFT, together with a tutorial on designing a DFP experiment to take advantage of all SFT measures in a single experiment. Illustrative examples are given to highlight the breadth of applicability of these techniques across psychology. We further introduce and demonstrate a new package for performing SFT analyses using R for statistical computing.
Valence and edibility are two important features of olfactory perception, but it remains unclear how they are read out from an olfactory input. For a given odor object (e.g., the smell of rose or garlic), does perceptual identification of that object necessarily precede retrieval of information about its valence and edibility, or alternatively, are these processes independent? In the present study, we studied rapid, binary perceptual decisions regarding odor detection, object identity, valence, and edibility for a set of common odors. We found that decisions regarding odor-object identity were faster than decisions regarding odor valence or edibility, but slower than detection. Mediation analysis revealed that odor valence and edibility decision response times were predicted by a model in which odor-object identity served as a mediator along the perceptual pathway from detection to both valence and edibility. According to this model, odor valence is determined through both a "low road" that bypasses odor objects and a "high road" that utilizes odor-object information. Edibility evaluations are constrained to processing via the high road. The results outline a novel causal framework that explains how major perceptual features might be rapidly extracted from odors through engagement of odor objects early in the processing stream. (PsycINFO Database Record (c) 2013 APA, all rights reserved).
A mathematical theory and related experimental methodology are developed that permit strong, converging tests of parallel versus serial versus channel summation processing and of exhaustive versus self-terminating processing. An experimental design is used for two studies, in which the presence or absence of a target in each of two positions, is factorially combined with two levels of brightness (a version of the double factorial paradigm). When both targets are present (redundant target condition) the two levels of brightness permit factorial technology to determine mental architecture and stopping rules. Comparison of the single versus double target conditions allows capacity analyses that strongly reinforce the double target factorial phase of the investigation. The results provide decisive support for parallel channels with either a self-terminating stopping rule or a coactive summation of information. General serial models and any variety of exhaustive processing were conclusively falsified.
In a typical visual search experiment, observers look through a set of items for a designated target that may or may not be present. Reaction time (RT) is measured as a function of the number of items in the display (set size), and inferences about the underlying search processes are based on the slopes of the resulting RT 〈 Set Size functions. Most search experiments involve 5 to 15 subjects perform- ing a few hundred trials each. In this retrospective study, I examine results from 2,500 experimental sessions of a few hundred trials each (approximately 1 million total trials). These data represent a wide variety of search tasks. The resulting picture of human search behav- ior requires changes in our theories of visual search.
A steady increase in reading speed is the hallmark of normal reading acquisition. However, little is known of the influence of visual attention capacity on children's reading speed. The number of distinct visual elements that can be simultaneously processed at a glance (dubbed the visual attention span), predicts single-word reading speed in both normal reading and dyslexic children. However, the exact processes that account for the relationship between the visual attention span and reading speed remain to be specified. We used the Theory of Visual Attention to estimate visual processing speed and visual short-term memory capacity from a multiple letter report task in eight and nine year old children. The visual attention span and text reading speed were also assessed. Results showed that visual processing speed and visual short term memory capacity predicted the visual attention span. Furthermore, visual processing speed predicted reading speed, but visual short term memory capacity did not. Finally, the visual attention span mediated the effect of visual processing speed on reading speed. These results suggest that visual attention capacity could constrain reading speed in elementary school children.
Meyer (1956) postulated that meaning in music is directly related to entropy–that high entropy (uncertainty) engenders greater subjective tension, which is correlated with more meaningful musical events. Current statistical models of music are often limited to music with a single melodic line, impeding wider investigation of Meyer's hypothesis. I describe a recurrent neural network model which produces estimates of instantaneous entropy for music with multiple parts and use it to analyze a Haydn string quartet. Features found by traditional analysis to be related to tension are shown to have characteristic signatures in the model's entropy measures. Thus, an information-based approach to musical analysis can elaborate on traditional understanding of music and can shed light on the more general cognitive phenomenon of musical meaning.
It is commonly believed that visual short-term memory (VSTM) consists of a fixed number of "slots" in which items can be stored. An alternative theory in which memory resource is a continuous quantity distributed over all items seems to be refuted by the appearance of guessing in human responses. Here, we introduce a model in which resource is not only continuous but also variable across items and trials, causing random fluctuations in encoding precision. We tested this model against previous models using two VSTM paradigms and two feature dimensions. Our model accurately accounts for all aspects of the data, including apparent guessing, and outperforms slot models in formal model comparison. At the neural level, variability in precision might correspond to variability in neural population gain and doubly stochastic stimulus representation. Our results suggest that VSTM resource is continuous and variable rather than discrete and fixed and might explain why subjective experience of VSTM is not all or none.
A dual-task paradigm with two primary tasks (visual and haptic) combined with two secondary tasks (visual and haptic) was used to assess visual-haptic working memory (WM) in young adults, older healthy adults, and mild cognitive impairment (MCI) adults. A corsi haptic device was constructed to avoid the use of vision while performing the haptic WM tasks. The MCI group obtained the smallest span measures on both modalities, and their poorer performance was on the haptic tasks
How much can we perceive and remember at a time? Results from various paradigms traditionally show that observers are aware of surprisingly little of the world around them. However, a recent study by Wu and Wolfe (Curr. Biol. 2018;28:3430–3434) uses a novel technique to reveal that observers have more knowledge of the visual world than previously believed.
Smell is a powerful tool for conveying and recalling information without requiring visual attention. Previous work identified, however, some challenges caused by user's unfamiliarity with this modality and complexity in the scent delivery. We are now able to overcome these challenges, introducing a training approach to familiarise scent-meaning associations (urgency of a message, and sender identity) and using a controllable device for the scent-delivery. Here we re-validate the effectiveness of smell as notification modality and present findings on the performance of smell in conveying information. In a user study composed of two sessions, we compared the effectiveness of visual, olfactory, and combined visual-olfactory notifications in a messaging application. We demonstrated that olfactory notifications improve users' confidence and performance in identifying the urgency level of a message, with the same reaction time and disruption levels as for visual notifications. We discuss the design implications and opportunities for future work in the domain of multimodal interactions.
The IEC 60601-1-8 international medical alarm standard was created to give engineers guidance for designing alarms that are easily perceivable by humans. Included within this are a number of reserved alarm sounds that use tonal melodies to represent common types of alarms. Despite the standard, practitioners can still fail to hear and respond to alarms. This can have a profound negative impact on patient life and health. One of the factors that contributes to this problem is simultaneous masking: a condition where one or more alarms can be rendered imperceptible in the presence of other alarms due to limitations of the human perception system. Unfortunately, the tonal nature of the IEC 60601-1-8 reserved sounds makes them particularly susceptible to masking. It can be difficult to determine how masking can manifest in a collection of alarms that can sound concurrently given the inherent complexity of the statespace. In this work, we employ a computational method that employs mathematical proof techniques to determine if masking is possible in a model of a configuration of medical alarms. We use this to analyze the low and medium priority reserved alarm sounds of the IEC 60601-1-8 standard. We describe our method, present the results of our analyses, discuss these results, and explore future research directions.
Many people are understandably excited by the suggestion that the chemical senses can be digitized; be it to deliver ambient fragrances (e.g., in virtual reality or health-related applications), or else to transmit flavour experiences via the internet. However, to date, progress in this area has been surprisingly slow. Furthermore, the majority of the attempts at successful commercialization have failed, often in the face of consumer ambivalence over the perceived benefits/utility. In this review, with the focus squarely on the domain of Human-Computer Interaction (HCI), we summarize the state-of-the-art in the area. We highlight the key possibilities and pitfalls as far as stimulating the so-called ‘lower’ senses of taste, smell, and the trigeminal system are concerned. Ultimately, we suggest that mixed reality solutions are currently the most plausible as far as delivering (or rather modulating) flavour experiences digitally is concerned. The key problems with digital fragrance delivery are related to attention and attribution. People often fail to detect fragrances when they are concentrating on something else; And even when they detect that their chemical senses have been stimulated, there is always a danger that they attribute their experience (e.g., pleasure) to one of the other senses – this is what we call ‘the fundamental attribution error’. We conclude with an outlook on digitizing the chemical senses and summarize a set of open-ended questions that the HCI community has to address in future explorations of smell and taste as interaction modalities.
Many studies have demonstrated the benefits of wearable vibration devices for walking navigation (Tsukada and Yasumura, 2004). Despite the potential benefits, suitable body parts for wearable vibration devices have not been defined or evaluated until now. We conducted three experiments to identify suitable body parts in terms of perceivability, wearability and user body location preferences for vibration devices. We tested vibration feedback on nine body parts (the ear, neck, chest, waist, wrist, hand, finger, ankle and foot). Experiment 1 and Experiment 2 were conducted in the lab and in real-world walking settings in order to find suitable body parts. Our results indicate that the finger, wrist, ear, neck and feet had the highest perceivability and user preferences. Experiment 3 was conducted to understand the practical usability of those vibration positions in walking navigation. Our study results suggested that the feet are not suitable locations for vibration feedback in walking navigation. Based on the study results, we present design implications and guidelines for wearable vibration devices.
The idea of one's memory "filling up" is a humorous misconception of how memory in general is thought to work; it actually has no capacity limit. However, the idea of a "full brain" makes more sense with reference to working memory, which is the limited amount of information a person can hold temporarily in an especially accessible form for use in the completion of almost any challenging cognitive task. This groundbreaking book explains the evidence supporting Cowan's theoretical proposal about working memory capacity, and compares it to competing perspectives. Cognitive psychologists profoundly disagree on how working memory is limited: whether by the number of units that can be retained (and, if so, what kind of units and how many), the types of interfering material, the time that has elapsed, some combination of these mechanisms, or none of them. The book assesses these hypotheses and examines explanations of why capacity limits occur, including vivid biological, cognitive, and evolutionary accounts. The book concludes with a discussion of the practical importance of capacity limits in daily life. This 10th anniversary Classic Edition will continue to be accessible to a wide range of readers and serve as an invaluable reference for all memory researchers.
Although our subjective impression is of a richly detailed visual world, numerous empirical results suggest that the amount of visual information observers can perceive and remember at any given moment is limited. How can our subjective impressions be reconciled with these objective observations? Here, we answer this question by arguing that, although we see more than the handful of objects, claimed by prominent models of visual attention and working memory, we still see far less than we think we do. Taken together, we argue that these considerations resolve the apparent conflict between our subjective impressions and empirical data on visual capacity, while also illuminating the nature of the representations underlying perceptual experience. Numerous empirical results highlight the limits of visual perception, attention, and working memory. However, it intuitively feels as though we have a rich perceptual experience, leading many to claim that conscious perception overflows these limited cognitive mechanisms.A relatively new field of study (visual ensembles and summary statistics) provides empirical support for the notion that perception is not limited and that observers have access to information across the entire visual world.Ensemble statistics, and scene processing in general, also appear to be supported by neural structures that are distinct from those supporting object perception. These distinct mechanisms can work partially in parallel, providing observers with a broad perceptual experience.Moreover, new demonstrations show that perception is not as rich as is intuitively believed. Thus, ensemble statistics appear to capture the entirety of perceptual experience.
A method of estimating an upper bound of the entropy of printed Chinese is presented. A bound of 5.17 bits/character for the entropy is obtained by computing the entropy of the sample of Chinese corpus. The perplexity of several language models, which is a quantitative measurement for the ability of language models, is discussed. A new method of approximating high scale language model by the lower ones is also presented.
This book is the magnum opus of one of the most influential cognitive psychologists of the past 50 years. This new volume on the model he created (with Graham Hitch) discusses the developments that have occurred in the past 20 years, and places it within a broader context. Working memory is a temporary storage system that underpins onex' capacity for coherent thought. Some 30 years ago, Baddeley and Hitch proposed a way of thinking about working memory that has proved to be both valuable and influential in its application to practical problems. This book updates the theory, discussing both the evidence in its favour, and alternative approaches. In addition, it discusses the implications of the model for understanding social and emotional behaviour, concluding with an attempt to place working memory in a broader biological and philosophical context. Inside are chapters on the phonological loop, the visuo-spatial sketchpad, the central executive and the episodic buffer. There are also chapters on the relevance to working memory of studies of the recency effect, of work based on individual differences, and of neuroimaging research. The broader implications of the concept of working memory are discussed in the chapters on social psychology, anxiety, depression, consciousness, and on the control of action. Finally, the author discusses the relevance of a concept of working memory to the classic problems of consciousness and free will.
Rauding theory makes precise predictions about the amount of passage comprehension; the accuracy of these predictions was investigated under different purpose conditons and differing rates of presentation. Passages at Grade 10 difficulty were presented to 102 college students at rates varying from 62.5 to 100,000 words per minute using motion picture film. The two purpose conditions were: (a) get the "gist," and (b) detect the missing verbs. Four different measurement techniques were used and all indicated that the amount comprehended was not substantially affected by purpose. Comprehension was generally high at the low rates, but it was approximately zero at 1,000 words per minute and greater. The amount of comprehension at each rate was accurately predicted from rauding theory. The data do not support the idea that individuals can read unfamiliar but relatively easy material at high rates with high accuracy of comprehension, but they do provide strong support for rauding theory./// [French] La théorie "rauding" fait des prédictions précises sur la quantité de compréhension de passage; on a examiné la précision de ces prédictions dans des conditions de buts différents et des taux de présentation changeants. On a presenté des passages de difficulté du niveau de la seconde à 102 étudiants universitaires à des taux variante de 62.5 a 100.000 mots minute en utilisant un film. On a dit à la moitié des étudiants que leur but premier pour la lecture était de tirer la substance du passage et à l'autre moitié que leur but premier était de détecter les verbes manquant. On a utilisé quatre techniques différentes pour mesurer la quantité comprise - jugement de compréhension, verbes manquant, test des meilleurs titres, et test des moitiés de phrase - et toutes ont reflété approximativement les mêmes résultats. La quantité comprise n'était pas suffisamment affectée par le but premier pour la lecture, mais elle l'était par le taux. La compréhension était généralement élevée, aux taux bas, mais elle était approximativement nulle à 1000 mots minute et plus. La quantité de compréhension à chaque taux était prédite avec précision à partir de la théorie "rauding"; l'erreur de prédiction moyenne était d'environ 4 points pourcentage. Les données ne supportent pas l'idée que les individus peuvent lire un matériel inhabituel mais relativement facile à des taux élevés avec une grande précision de compréhension mais ces données fournissent bien un fort support pour la théorie "rauding"./// [Spanish] La teoría de "rauding" hace predicciones precisas sobre la magnitud de comprensión de un pasaje de lectura; la precisión de estas predicciones se investigó bajo diferentes objetivos y variadas velocidades de presentación. Se dieron pasajes de nivel de dificultad de grado 10, por medio de películas, a 102 estudiantes universitarios, a velocidades que variaban de 62,5 a 100.000 palabras por minuto. Los dos objetivos eran: (a) reconocer lo esencial, y (b) percibir los verbos no existentes. Se utilizaron 4 técnicas de medición y todas indicaron que la magnitud comprendida no fue afectada considerablemente por el objetivo. Generalmente, la comprensión era alta a velocidades lentas, pero era casi cero a mil o más palabras por minuto. La magnitud de comprensión a cada velocidad fue predicha con precisión por medio de la teoría de "rauding". Los datos no soportan la idea que individuos pueden leer material desconocido, pero relativamente fácil, a grandes velocidades y con gran exactitud de comprensión, pero sí soportan fuertemente la teoría de "rauding".
We introduce UltraHaptics, a system designed to provide multi-point haptic feedback above an interactive surface. UltraHaptics employs focused ultrasound to project discrete points of haptic feedback through the display and directly on to users' unadorned hands. We investigate the desirable properties of an acoustically transparent display and demonstrate that the system is capable of creating multiple localised points of feedback in mid-air. Through psychophysical experiments we show that feedback points with different tactile properties can be identified at smaller separations. We also show that users are able to distinguish between different vibration frequencies of non-contact points with training. Finally, we explore a number of exciting new interaction possibilities that UltraHaptics provides.
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Several tests were given to determine the rate of transmission of information through the human channel when the information was encoded in one to five flashing lights and S's output was pressing corresponding keys. All possible stimulus bulbs were equally probable and any number could be lighted simultaneously. (1) Increasing the stimulus rate increased the information transmission rate only up to a point where S was making a few errors. (2) Increasing the number of possible light bulbs from one through five more than tripled the maximum transmission rate. (3) Reaction time was not a function of stimulus rate. (4) The reaction time increased with the number of possible light bulbs in the stimulus but not linearly. (5) Maximum transmission occurred at a rate very close numerically to the reciprocal of the reaction time. (6) The self-pacing test resulted in as high transmission as the forced rate tests.
Visual working memory capacity is of great interest because it is strongly correlated with overall cognitive ability, can be understood at the level of neural circuits, and is easily measured. Recent studies have shown that capacity influences tasks ranging from saccade targeting to analogical reasoning. A debate has arisen over whether capacity is constrained by a limited number of discrete representations or by an infinitely divisible resource, but the empirical evidence and neural network models currently favor a discrete item limit. Capacity differs markedly across individuals and groups, and recent research indicates that some of these differences reflect true differences in storage capacity whereas others reflect variations in the ability to use memory capacity efficiently.
A new method of estimating the entropy and redundancy of a language is described. This method exploits the knowledge of the language statistics possessed by those who speak the language, and depends on experimental results in prediction of the next letter when the preceding text is known. Results of experiments in prediction are given, and some properties of an ideal predictor are developed.
Our sensory modalities are specialized in perceiving different attributes of an object or event. This fact is the basis of the approach towards multimodal interfaces we describe in this paper. We rated the match between 20 possible information attributes (common in human computer interaction) and the visual, auditory and tactile sensory systems. We refer to this match as modality appropriateness. Preferably, an information chunk is allocated to the most appropriate modality. In situations in which information consists of several attributes, these may be allocated to different modalities. This approach is in contrast with the more common approach in which multimodality is implemented in an interface as a redundant presentation of the same information to two or more sensory modalities. This latter approach can be beneficial to solve risks of sensory overload and to make the interface accessible for people with a sensory challenge, but is not based on possible synergy between the senses. However, the supposed synergy may also involve costs, for example in terms of the time required to switch between modalities and in the introduction of additional noise in cross-modal comparisons compared to unimodal comparisons. We will discuss both the chances and the potential costs of applying the modality appropriateness framework.
Previous studies have shown that behavioral responses to auditory, visual, and tactile stimuli are modulated by expectancies
regarding the likely modality of an upcoming stimulus (see Spence & Driver, 1997). In the present study, we investigated whether
people can also selectively attend to the chemosensory modality (involving responses to olfactory, chemical, and painful stimuli).
Participants made speeded spatial discrimination responses (left vs. right) to an unpredictable sequence of odor and tactile
targets. Odor stimuli were presented to either the left or the right nostril, embedded in a birhinally applied constant airstream.
Tactile stimuli were presented to the left or the right hand. On each trial, a symbolic visual cue predicted the likely modality
for the upcoming target (the cue was a valid predictor of the target modality on the majority of trials). Response latencies
were faster when targets were presented in the expected modality than when they were presented in the unexpected modality,
showing for the first time that behavioral responses to chemosensory stimuli can be modulated by selective attention.
Visual analysis appears to be functionally divided between an early preattentive level of processing at which simple features are coded spatially in parallel and a later stage at which focused attention is required to conjoin the separate features into coherent objects. Evidence supporting this dichotomy comes from behavioral studies of visual search, from differences in the ease of texture segregation, from reports of illusory conjunctions when attention is overloaded, from subjects' ability to identify simple features correctly even when they mislocate them, and from the substantial benefit of pre-cuing the location of a relevant item when the task requires that features be conjoined but not when simple features are sufficient. Some further studies of search have revealed a striking asymmetry between several pairs of stimuli which differ in the presence or absence of a single part or property. The asymmetry depends solely on which of the pair is allocated the role of target and which is replicated to form the background items. It suggests that search for the presence of a visual primitive is automatic and parallel, whereas search for the absence of the same feature is serial and requires focused attention. The search asymmetry can be used as an additional diagnostic to help define the functional features extracted by the visual system.
Reaction times to varying concentrations of the four basic taste stimuli (sucrose, NaCl, tartaric acid and quinine-HCl) were measured in twenty human adults. Reaction times decreased with increasing concentrations of solutions, and the relationships between the reaction time and the concentration are described by a rectangular hyperbola for all the four tastes. The reaction times to the strongest solutions used in this experiment were about 400 msec for NaCl and tartaric acid and about 700 msec for sucrose and quinine solutions. Since the reaction time to flow of water on the tongue surface was around 200 msec, we concluded that the minimum taste encoding time was 200 msec or less for the high concentrations of salt and acid solutions.
Individual differences in reading comprehension may reflect differences in working memory capacity, specifically in the trade-off between its processing and storage functions. A poor reader's processes may be inefficient, so that they lessen the amount of additional information that can be maintained in working memory. A test with heavy processing and storage demands was devised to measure this trade-off. Subjects read aloud a series of sentences and then recalled the final word of each sentence. The reading span, the number of final words recalled, varied from two to five for 20 college students. This span correlated with three reading comprehension measures, including verbal SAT and tests involving fact retrieval and pronominal reference. Similar correlations were obtained with a listening span task, showing that the correlation is not specific to reading. These results were contrasted with traditional digit span and word span measures which do not correlate with comprehension.