Embodied gestalts: Unstable visual phenomena become stable when they are stimuli for competitive action selection.

An animal's environment is rich with affordances. Different possible actions are specified by visual information while competing for dominance over neural dynamics. Affordance competition models account for this in terms of winner-takes-all cross-inhibition dynamics.

Bernstein's levels of movement construction: A contemporary perspective.

Explanation of how goal-directed movements are made manifest is the ultimate aim of the field classically referred to as "motor control". Essential to the sought-after explanation is comprehension of the supporting functional architecture. Seven decades ago, the Russian physiologist and movement scientist Nikolai A.

Effects of visual and auditory guidance on bimanual coordination complexity.

Perceptual guidance of movement with simple visual or temporal information can facilitate performance of difficult coordination patterns. Guidance may override coordination constraints that usually limit stability of bimanual coordination to only in-phase and anti-phase. Movement dynamics, however, might not have the same characteristics with and without perceptual guidance.

Anticipation in manual tracking with multiple delays.

Two experiments are reported showing that behavior exhibited in manual tracking is consistent with behavior predicted by a dynamical systems phenomenon known as anticipating synchronization (Voss, 2000). They extend a prior investigation of the effect of delay on anticipatory manual tracking (Stepp, 2009) by also manipulating coupling strength. The coupling scheme in Experiment 1 and that in Experiment 2 go beyond the single delayed feedback coupling used in previous research and articulations of anticipating synchronization.

Non-obvious influences on perception-action abilities.

The sciences of development and learning have been slow to acknowledge that absence of an identifiable experience that relates straightforwardly to a given perception-action ability need not mean that experience per se is irrelevant to the emergence of that ability. A recent study reveals that a difference in diet (plain vs. energy rich) leads to a difference in how rats navigate (use of geometry vs.

Size and distance are perceived independently in an optical tunnel: Evidence for direct perception.

The historical but questionable size-distance invariance hypothesis (SDIH) features computation over geometric, oculomotor, and binocular cues and the coupling of percepts-perceived size, S', is mediated by perceived distance, D'. A contemporary non-mediational hypothesis holds that S' and D' are specific to distinct optical variables. We report two experiments with an optical tunnel, an arrangement of alternating black and white concentric rings, that allows systematic manipulation of the optic array at a point of observation while controlling a variety of size and depth cues.

Affordance-based perception-action dynamics: A model of visually guided braking.

Behavioral dynamics is a framework for understanding adaptive behavior as arising from the self-organizing interaction between animal and environment. The methods of nonlinear dynamics provide a language for describing behavior that is both stable and flexible. Behavioral dynamics has been criticized for ignoring the animal's sensitivity to its own capabilities, leading to the development of an alternative framework: affordance-based control.

Haptic perceptual intent in quiet standing affects multifractal scaling of postural fluctuations.

Research on dynamic touch has shown that when a rod strapped to the shoulders is wielded via axial rotations, flexions-extensions, and lateral bending of the trunk, participants can selectively perceive whole rod length and partial rod length (e.g., a leftward segment) with precision comparable to wielding by hand (Palatinus, Carello & Turvey, 2011).

The medium of haptic perception: a tensegrity hypothesis.

For any given animal, the sources of mechanical disturbances inducing tissue deformation define environment from the perspective of the animal's haptic perceptual system. The system's achievements include perceiving the body, attachments to the body, and the surfaces and substances adjacent to the body. Among the perceptual systems, it stands alone in having no defined medium.

Balance affects prism adaptation: evidence from the latent aftereffect.

In prism adaptation experiments, the effect on throwing to a target is reduced (primary aftereffect is smaller) when the throwing condition with prisms removed (first test phase) is different from the throwing condition with prisms (the training phase). The missing adaptation, however, can be revealed through further testing (second test phase) in which the throwing condition during training is fully reinstated. We studied throwing underhand to a target flush with the floor.

Negative hysteresis in the behavioral dynamics of the affordance "graspable".

One commonly perceives whether a visible object will afford grasping with one hand or with both hands. In experiments in which differently sized objects of a fixed type are presented, the transition from using one of these manual modes to the other depends on the ratio of object size to hand span and on the presentation sequence, with size increasing versus decreasing. Conventional positive hysteresis (i.

Symmetry breaking analysis of prism adaptation's latent aftereffect.

The effect of prism adaptation on movement is typically reduced when the movement at test (prisms off) differs on some dimension from the movement at training (prisms on). Some adaptation is latent, however, and only revealed through further testing in which the movement at training is fully reinstated. Applying a nonlinear attractor dynamic model (Frank, Blau, & Turvey, 2009) to available data (Blau, Stephen, Carello, & Turvey, 2009), we provide evidence for a causal link between the latent (or secondary) aftereffect and an additive force term that is known to account for symmetry breaking.

The role of haptic information in shaping coordination dynamics: inertial frame of reference hypothesis.

Current research suggests that non-visual perception of the spatial orientation of body segments is tied to vectors representative of their mass moment distribution (v(mm)). Our question was whether the relative orientation of v(mm) of right and left hands (Δv(mm)=v(mm) left-v(mm) right) constitutes haptic information supporting bimanual coordination and, if so, how it contributes to coordination dynamics. Blindfolded participants coordinated the motions of a pair of cross-shaped, hand-held pendulums that were either symmetrically loaded (Δv(mm)=0) or asymmetrically loaded (Δv(mm)≠0).

Behavioral dynamics of the affordance "graspable".

On a daily basis, one perceives whether an object affords grasping with one hand or with both hands. In experiments in which differently sized objects of a fixed type have been presented, the transition from using one manual mode to the other has depended on both the ratio of object size to hand span and the presentation sequence-that is, size increasing versus decreasing. The transitions and their observed hysteresis (i.

Philosophy for the rest of cognitive science.

Cognitive science has always included multiple methodologies and theoretical commitments. The philosophy of cognitive science should embrace, or at least acknowledge, this diversity. Bechtel's (2009a) proposed philosophy of cognitive science, however, applies only to representationalist and mechanist cognitive science, ignoring the substantial minority of dynamically oriented cognitive scientists.

Place learning by mechanical contact.

For some animals (e.g. the night-active wandering spider) the encounters with the habitat that result in place learning are predominantly mechanical.

Human odometer is gait-symmetry specific.

In 1709, Berkeley hypothesized of the human that distance is measurable by 'the motion of his body, which is perceivable by touch'. To be sufficiently general and reliable, Berkeley's hypothesis must imply that distance measured by legged locomotion approximates actual distance, with the measure invariant to gait, speed and number of steps. We studied blindfolded human participants in a task in which they travelled by legged locomotion from a fixed starting point A to a variable terminus B, and then reproduced, by legged locomotion from B, the A-B distance.

Dispersion of response times reveals cognitive dynamics.

Trial-to-trial variation in word-pronunciation times exhibits 1/f scaling. One explanation is that human performances are consequent on multiplicative interactions among interdependent processes-interaction dominant dynamics. This article describes simulated distributions of pronunciation times in a further test for multiplicative interactions and interdependence.

Nature of motor control: perspectives and issues.

Four perspectives on motor control provide the framework for developing a comprehensive theory of motor control in biological systems. The four perspectives, of decreasing orthodoxy, are distinguished by their sources of inspiration: neuroanatomy, robotics, self-organization, and ecological realities. Twelve major issues that commonly constrain (either explicitly or implicitly) the understanding of the control and coordination of movement are identified and evaluated within the framework of the four perspectives.

Autonomy and hypersets.

This paper has two primary aims. The first is to provide an introductory discussion of hyperset theory and its usefulness for modeling complex systems. The second aim is to provide a hyperset analysis of several perspectives on autonomy: Robert Rosen's metabolism-repair systems and his claim that living things are closed to efficient cause, Maturana and Varela's autopoietic systems, and Kauffman's cataytically closed systems.

Phonological assimilation and visual word recognition.

Are the visual word-processing tasks of naming and lexical decision sensitive to systematic phonological properties that may or may not be specified in the spelling? Two experiments with Hangul, the alphabetic orthography of Korea, were directed at the effects of the phonological process of assimilation whereby one articulation changes to conform to a neighboring articulation. Disyllabic words were responded to more quickly when (a) the final letter of the first syllable and the initial letter of the second syllable specified phonemes that satisfied rather than violated consonant assimilation, and (b) the vowel letters specified harmonious as opposed to disharmonious vowel phonemes. Discussion addressed the possible mediation of assimilation effects by consistency differences and theories that predict broad phonological influences on visual word recognition.

Effects of visual environment on quiet standing by young and old adults.

The authors manipulated the circumstances in which individuals are typically embedded when standing upright by manipulating the intensity of light and the stationary structure of the environment. They expected that the manipulations would affect 12 older participants (aged 65-82 years) more than it would 12 younger participants (aged 22-24 years). Linear (e.

Encoding and retrieval during bimanual rhythmic coordination.

In 2 experiments, bimanual 1:1 rhythmic coordination was performed concurrently with encoding or retrieval of word lists. Effects of divided attention (DA) on coordination were indexed by changes in mean relative phase and recurrence measures of shared activity between the 2 limbs. Effects of DA on memory were indexed by deficits in recall relative to baseline.