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ABSTRACT: For skills that involve hitting a target, subsequent judgments of target size correlate with prior success in hitting that target. We used an archery context to examine the judgment-success relationship with varied target sizes in the absence of explicit knowledge of results. Competitive archers shot at targets 50 m away that varied in size among five diameters. Immediately after the arrow's release, its flight and landing were occluded and archers chose which of 18 miniature targets looked most like the distal target. Greater apparent size correlated with higher accuracy. In a second experiment, nonarchers merely aimed the bow (without an arrow) at varied targets. Apparent size was larger when the bow arm was stabilized than when it was not. Archery is seemingly an instance of affordance-based control: For an archer, the affordance of the target is the "hitableness" of its central regions, a property inclusive of his or her momentary, and perceptible, archery form. (PsycINFO Database Record (c) 2012 APA, all rights reserved).
Journal of Experimental Psychology Human Perception & Performance 06/2012; 38(5):1125-31. · 3.06 Impact Factor
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ABSTRACT: Bipedal gaits have been classified on the basis of the group symmetry of the minimal network of identical differential equations (alias cells) required to model them. Primary gaits are characterized by dihedral symmetry, whereas secondary gaits are characterized by a lower, cyclic symmetry. This fact was used in a test of human odometry. Results suggest that when distance is measured and reported by gaits from the same symmetry class, primary and secondary gaits are comparable. Switching symmetry classes at report compresses (primary to secondary) or inflates (secondary to primary) measured distance, with the compression and inflation equal in magnitude. Lessons are drawn from modeling the dynamics of behaviors executed in parallel (e.g., interlimb coordination) to model the dynamics of human odometry, in which the behaviors are executed sequentially. The major observations are characterized in terms of a dynamics of sequentially coupled measure and report phases, with relative velocity as an order parameter, or equilibrium state, and difference in symmetry class as an imperfection parameter, or detuning, of that dynamic.
Journal of Experimental Psychology Human Perception & Performance 04/2012; 38(4):1014-25. · 3.06 Impact Factor
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ABSTRACT: A nonword prime can sound like a target word or one of the target’s associates, and it can look like either without sounding
like either. These pseudohomophones and pseudohomographs can vary in the number of letters shared with the target or its associate.
In an associative priming experiment in which targets were named and prime duration was 125 msec within a mask-prime-mask-target
sequence, pseudohomophones primed and pseudohomographs did not, with the pseudoassociative priming being only weakly affected
by spelling differences. In three further experiments, prime homophony and homography were defined in respect to the target.
Prime durations were 125 and 21 msec within a maskprime-mask-target sequence and 57 msec vrithin a mask-prime-target sequence.
The superior priming by pseudohomophones was relatively insensitive to spelling. Results are discussed in terms of the phonological
coherence hypothesis and the roles for orthographic information implied by the hypothesis.
Attention Perception & Psychophysics 04/2012; 62(1):196-217. · 2.04 Impact Factor
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ABSTRACT: Reading a word may involve the spoken language in two ways: in the conversion of letters to phonemes according to the conventions of the language's writing system and the assimilation of phonemes according to the language's constraints on speaking. If so, then words that require assimilation when uttered would require a change in the phonemes produced by grapheme-phoneme conversion when read. In two experiments, each involving 40 fluent readers, we compared visual lexical decision on Korean orthographic forms that would require such a change (C stimuli) or not (NC stimuli). We found that NC words were accepted faster than C words, and C nonwords were rejected faster than NC nonwords. The results suggest that phoneme-to-phoneme transformations involved in uttering a word may also be involved in visually identifying the word.
Journal of Psycholinguistic Research 04/2012; · 0.59 Impact Factor
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ABSTRACT: Humans and other animals can measure distances nonvisually by legged locomotion. Experiments typically employ an outbound measure (M) and an inbound report (R) phase. Previous research has found distance reproduction to be maximally accurate, when gait symmetry and speed of M and R are of like kind: Successful human odometry manifests at the level of the M-R system. In the present work, M was an experimenter-set distance produced by a blindfolded participant using a primary gait (walk, run). R was always by walk. Fast and slow versions of walk and run were adopted by participants, such that when M was fast R was slow, and vice versa. Distance was underestimated when M was slower than R and overestimated when M was faster than R. However, the pattern of participant-adopted velocities indicated that it was the instructions, not the speed as such, that yielded the pattern of results. The results are interpretable through a dynamical perspective and indicate speed is an imperfection parameter acting on the attractors of the M-R system.
Journal of Motor Behavior 01/2012; 44(1):47-52. · 1.64 Impact Factor
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ABSTRACT: Dynamic touching is effortful touching. It entails deformation of muscles and fascia and activation of the embedded mechanoreceptors, as when an object is supported and moved by the body. It is realized as exploratory activities that can vary widely in spatial and temporal extents (a momentary heft, an extended walk). Research has revealed the potential of dynamic touching for obtaining non-visual information about the body (e.g. limb orientation), attachments to the body (e.g. an object's height and width) and the relation of the body both to attachments (e.g. hand's location on a grasped object) and surrounding surfaces (e.g. places and their distances). Invariants over the exploratory activity (e.g. moments of a wielded object's mass distribution) seem to ground this 'information about'. The conception of a haptic medium as a nested tensegrity structure has been proposed to express the obtained information realized by myofascia deformation, by its invariants and transformations. The tensegrity proposal rationalizes the relative indifference of dynamic touch to the site of mechanical contact (hand, foot, torso or probe) and the overtness of exploratory activity. It also provides a framework for dynamic touching's fractal nature, and the finding that its degree of fractality may matter to its accomplishments.
Philosophical Transactions of The Royal Society B Biological Sciences 11/2011; 366(1581):3123-32. · 6.40 Impact Factor
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ABSTRACT: When a person standing upright raises an arm on cue, muscles of the left and right sides of the body exhibit changes prior to and specific to the responding arm. We had standing participants perform a visual lexical decision task ("is this letter string a word?"), responding yes by raising one arm and no by raising the other arm. We recorded onset of the arm movement and onset of electromyographic activity in thigh, trunk, and shoulder muscles. We observed the expected responding arm specificity and found that the onset difference favoring word decisions was evident in similar magnitude at all measurement sites, with the difference at the levels of thigh, trunk and shoulder muscles available 225, 189, and 120 ms, respectively, prior to its manifestation at the level of arm movement. We discuss including (a) whole body reaction time along with event-related potentials in determining the decision-response, brain-body temporal relation and (b) response execution along with response initiation in investigating mental chronometry.
Neuroscience Letters 02/2011; 490(2):126-9. · 2.11 Impact Factor
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ABSTRACT: The haptic subsystem of dynamic touch expresses a novel form of part-whole selective perception. When wielding a nonvisible rod grasped at some intermediate point along its length, an individual can attend to and report the length of a part of the rod (e.g., the segment forward of the hand) or the length of the whole rod. Both perceptions relate to the rod's mass moments about the point of grasp but in systematically different ways. Previous demonstrations of this part-whole selectivity have been in respect to rods grasped by hand or attached to a foot. The authors demonstrated the part-whole selectivity for nonvisible rods attached to the shoulder girdle and wielded primarily by movements of the trunk with benchmark performance provided by the same rods grasped and wielded by hand. Their results suggest that part-whole selectivity is a haptic capability general to the body.
Journal of Motor Behavior 02/2011; 43(2):87-93. · 1.64 Impact Factor
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ABSTRACT: The current research distinguishes two types of attention shifts: those entailed by perceptual learning and those entailed by changing intention. In perceptual learning, participants given feedback have been shown to gradually shift attention toward the optimal (i.e., specifying) information variable for the task. A shift in variable use is also expected when intention changes, because an intention to perceive some property entails attunement to information about that property. We compared the effects of feedback and intention in a dynamic (kinesthetic) touch task by representing both as changes of locus in an information space of inertial variables. Participants wielded variously sized, unseen, rectangular parallelepipeds and made length or width judgments about them. When given feedback, participants made gradual attentional shifts toward the optimal variable, which demonstrates the education of attention. When asked to report a new property, participants made large attentional jumps to the ballpark of the optimal variable for the new property. Exploratory movements were measured on 6 participants and were found to differ as a function of intention and to change with learning.
Attention Perception & Psychophysics 04/2010; 72(3):721-35. · 2.04 Impact Factor
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ABSTRACT: In a simple homing task with human participants, we disassociated the outbound distance travelled from the straight-line distance between home and target. Prior to the outbound journey, which involved a detour, participants were given one of two instructions concerning the inbound journey, which did not involve a detour: to walk the distance travelled or to walk to home. The inbound journey under each intention, made with eyes closed at a self-selected pace, was the measure of the perceived distance. We conducted two experiments that differed in whether or not the detour and target were visible during the outbound journey. In both experiments, we manipulated the load carried in the outbound journey (0% or 20% body weight) and the speed (fast or slow) of the outbound journey. The outcome of both experiments was that, indifferent to speed, participants perceived the distance travelled with load to be longer than that travelled without load, but perceived home's straight-line distance from target to be the same for both load conditions. Perceptions of travel distance and straight-line distance seem to be based on different information kinds and to refer to different animal-environment relations. In identifying neural mechanisms supportive of navigation, straight-line distance versus travelled distance may prove to be a productive distinction.
Neuroscience Letters 10/2009; 462(2):140-3. · 2.11 Impact Factor
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ABSTRACT: The effect of prism adaptation on movement is typically reduced when movement at test (with prisms removed) is different from movement at training. Previous research [J. Fernández-Ruiz, C. Hall-Haro, R. Díaz, J. Mischner, P. Vergara, J. C. Lopez-Garcia, Learning motor synergies makes use of information on muscular load, Learning & Memory 7 (2000) 193-198] suggests, however, that some adaptation is latent and only revealed through further testing in which the movement at training is fully reinstated. Movement in their training trials was throwing overhand to a vertical target with a mass attached to the arm. The critical test trials involved the same act initially without the attached mass and then with the attached mass. In replication, we studied throwing underhand to a horizontal target with left shifting prisms and a dissociation of the throwing arm's mass and moment of inertia. The two main results were that the observed latent aftereffect (a) depended on the similarity of training and test moments of inertia, and (b) combined with the primary aftereffect to yield a condition-independent sum. Discussion focused on a parallel between prism adaptation and principles governing recall highlighted in investigations of implicit memory: whether given training (study) conditions lead to good or poor persistence of adaptation (memory performance) at test depends on the conditions at test relative to the conditions at training (study).
Neuroscience Letters 07/2009; 456(2):54-8. · 2.11 Impact Factor
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ABSTRACT: Several experimental studies have shown that human grasping behavior exhibits a transition from one-handed to two-handed grasping when to-be-grasped objects become larger and larger. The transition point depends on the relative size of objects measured in terms of human body-scales. Most strikingly, the transitions between the two different behavioral 'modes' of grasping exhibit hysteresis. That is, one-to-two hand transitions and two-to-one hand transitions occur at different relative object sizes when objects are scaled up or down in size. In our study we approach body-scaled hysteresis and mode transitions in grasping by exploiting the notion that human behavior in general results from self-organization and satisfies appropriately-defined order parameter equations. To this end, grasping transitions and grasping hysteresis are discussed from a theoretical perspective in analogy to cognitive processes defined by Haken's neural network model for pattern recognition. In doing so, issues such as the exclusivity of grasping modes, biomechanical constraints, mode-mode interactions, single subject behavior and population behavior are explored.
Journal of Biological Physics 06/2009; 35(2):127-47. · 1.86 Impact Factor
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ABSTRACT: LW, an individual with a stroke-related motor impairment, was asked to perceive the lengths of rods of different mass distributions by dynamic touch. His impairment dictated that wielding was primarily about the shoulder rather than the wrist. Although perceived rod lengths were in the range of actual rod lengths, scaling to the objects' mass moments was atypical for both the affected and unaffected limbs. A group of healthy young adults asked to mimic his wielding style yielded the same atypical scaling. The typical scaling was restored when LW's wielding was fixed about a mechanical axis. Discussion considered what frame of reference is suitable for revealing an object's mass moments relevant to a given task. In particular, it appears that individuals can exploit alternative forms of interaction with environmental objects that leave invariant the parameters specifying to-be-perceived properties. Perception by dynamic touch is not a function of particular neuromuscular patterns but of information made available to the haptic system during limb-object interactions.
Ecological Psychology 01/2009; 21(4):291-307. · 1.19 Impact Factor
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ABSTRACT: Stress at one body segment can influence rhythmic movements of non-neighboring body segments. The nervous, circulatory, and fascia (connective tissue) systems are potential mediators of such remote effects. Assessing them begins with a detailed description of the remote effects. Precisely, how do the rhythmic movements change? In our experiment with seven participants, left-hand oscillations of held pendulums at self-selected frequencies were examined as a function of right-hand tonic forces of 0, 10 or 20% of the maximum voluntary contraction. We evaluated the effect of the right hand's tonic force on the amplitude and frequency, and the stiffness and friction functions of the left hand's oscillations. Our results suggest that (a) amplitude and stiffness (both linear and non-linear) increased with tonic force but frequency and friction (both linear and non-linear) did not, and (b) the stiffness increases due to right hand 10 and 20% stress were indifferent to the initial (0%) left-hand stiffness values. Discussion took note of how the nervous system and architectural features of the body (e.g., its network of connective tissue) may produce such effects.
Neuroscience Letters 01/2008; 429(1):64-8. · 2.11 Impact Factor
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M T Turvey
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ABSTRACT: Meeting the challenge of assembling coherent organizations of very many muscles characterizes a functional level of biological movement systems referred to as the level of muscular-articular links or synergies. The present article examines the issues confronting the forming, regulating, and ordering of synergies and the hypothesized principles, both classical and contemporary, which resolve them. A primary goal of the article is to highlight the abstractness of the concepts and tools required to understand the level's action-perception competence. Coverage is given to symmetry groups, task space, order parameters, metastability, biotensegrity, allometric scaling, and impredicative definitions.
Human Movement Science 09/2007; 26(4):657-97. · 1.77 Impact Factor
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ABSTRACT: Weaker inter- than intramodality long-term priming of words has promoted two hypotheses: (1) separate visual and auditory lexicons and (2) modality dependence of implicit memory. In five experiments, we employed manipulations aimed to minimize study-test asymmetries between the two priming conditions. Activities at visual and auditory study were matched, words were phonologically consistent, and study modality was manipulated between subjects. Equal magnitudes of inter- and intramodality priming were found in experiments with visual and auditory stem completion at test, with visual fragment completion at test, and with visual and auditory perceptual identification at test. A within-subjects experiment yielded the conventional intramodality advantage. The results point to a single amodal lexicon and to modality-independent phonological processing as the basis of implicit word memory.
Memory & Cognition 07/2007; 35(4):781-800. · 1.92 Impact Factor
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ABSTRACT: Nonvisual perceptions of a wielded object's spatial properties are based on the quantities expressing the object's mass distribution, quantities that are invariant during the wielding. The mechanoreceptors underlying the kind of haptic perception involved in wielding - referred to as effortful, kinesthetic, or dynamic touch - are those embedded in the muscles, tendons, and ligaments. The present experiment's focus was the selectivity of this muscle-based form of haptic perception. For an occluded rod grasped by the hand at some intermediate position along its length, participants can attend to and report selectively the rod's full length, its partial lengths (fore or aft of the hand), and the position of the grip. The present experiment evaluated whether participants could similarly attend selectively when wielding by foot. For a given rod attached to and wielded by foot or attached to (i.e. grasped) and wielded by hand, participants reported (by magnitude production) the rod's whole length or fractional length leftward of the point of attachment. On measures of mean perceived length, accuracy, and reliability, the degree of differentiation of partial from full extent achieved by means of the foot matched that achieved by means of the hand. Despite their neural, anatomical, and experiential differences, the lower and upper limbs seem to abide by the same principles of selective muscle-based perception and seem to express this perceptual function with equal facility.
Neuroscience Letters 06/2007; 419(1):5-9. · 2.11 Impact Factor
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ABSTRACT: Bimanual 1:1 rhythmic coordination was performed while retrieving words from a specified category. The effects of divided attention (DA) on coordination were indexed by changes in mean relative phase and recurrence measures of shared activity between the two limbs. Effects of DA on memory were indexed by deficits in exemplars retrieved relative to the baseline. Shifts in relative phase were found, accompanied by a recall deficit for DA during the retrieval task. DA also reduced the degree of shared activity between left and right rhythmic motions. Our discussion focuses on DA-induced parameter changes in retrieval and coordination dynamics, as well as on the hypothesis that stability is the general factor mediating dual-task performance.
Psychonomic Bulletin & Review 01/2007; 13(6):985-90. · 2.61 Impact Factor
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ABSTRACT: The spatial extents of hand-held objects can be perceived nonvisually by wielding them. This ability of effortful or dynamic touch to exploit the mass moments of an object to perceive its length was evaluated with a 40-years old right-handed woman with surgically treated Arnold-Chiari Type 1 Malformation and cervical syrinx. At the time of the experiment she presented with loss of discriminative touch in the left arm but no comparable sensory deficits in the right arm or the lower extremities. She could neither identify objects in her left hand nor tell that they were in the hand while manipulating them. She could, however, grasp an object tightly and wield it on request. In the experiment she wielded weighted rods of 45, 60, and 80cm length about the wrist. There were two main results. First, her nonvisual perception of rod length by the insensate left arm scaled systematically with rod moment of inertia. The scaling matched that of the intact right arm and the nondominant arm of haptically unimpaired controls tested with rods of similar dimensions. Second, her right arm was superior in accuracy and reliability than her insensate left arm and was equal to or better than the dominant arm of the control group on key measures of nonvisual length perception. The first result was evaluated in respect to the notions of numb touch and differences in the neural bases of discriminative and effortful touch. The second result was discussed in terms of contralateral cortical enhancement by deafferentation.
Neuroscience Letters 10/2006; 405(3):159-63. · 2.11 Impact Factor
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ABSTRACT: A simple instance of coupling behavior to the environment is oscillating the hands in pace with metronome beats. This environmental coupling can be weaker (1 beat per cycle) or stronger (2 beats per cycle). The authors examined whether strength of environmental coupling enhanced the stability of in-phase bimanual coordination. Detuning by manipulanda that produced different left and right eigenfrequencies shifted the relative phase angle from 0 degrees, with the size of the shift larger for higher movement frequencies. Stronger environmental coupling was found to decrease this relative-phase shift, with accompanying increase and reduction, respectively, in recurrence quantification measures related to coordination stability and coordination noise. Stronger environmental coupling also increased oscillation amplitude. Results are considered from the perspective of parametric stabilization.
Journal of Experimental Psychology Human Perception & Performance 07/2006; 32(3):599-609. · 3.06 Impact Factor
