Kevin Shockley

Mutual interpersonal postural constraints are involved in cooperative conversation.

The research was designed to evaluate interpersonal coordination during conversation with a new measurement tool. The experiment uses an analysis based on recurrence strategies, known as cross recurrence quantification, to evaluate the shared activity between 2 postural time series in reconstructed phase space. Pairs of participants were found to share more locations in phase space (greater recurrence) in conditions where they were conversing with one another to solve a puzzle task than in conditions in which they convened with others. The trajectories of pairs of participants also showed less divergence when they conversed with each other than when they conversed with others well. This is offered as objective evidence of interpersonal coordination of postural sway in the context of a cooperative verbal task.

Conversation and Coordinative Structures

People coordinate body postures and gaze patterns during conversation. We review literature showing that (1) action embodies cognition, (2) postural coordination emerges spontaneously when two people converse, (3) gaze patterns influence postural coordination, (4) gaze coordination is a function of common ground knowledge and visual information that conversants believe they share, and (5) gaze coordination is causally related to mutual understanding. We then consider how coordination, generally, can be understood as temporarily coupled neuromuscular components that function as a collective unit known as a coordinative structure in the motor control literature. We speculate that the coordination of gaze and body sway found in conversation may be understood as a cross-person coordinative structure that embodies the goals of the joint action system.

Imitation in shadowing words.

Imitation of shadowed words was evaluated using Goldinger’s (1998) AXB paradigm. The first experiment was a replication of Goldinger’s experiments with different tokens. Experiment 1’s AXB tests showed that shadowed words were judged to be better imitations of target words than were baseline (read) counterparts more often than chance (.50). Order of presentation of baseline and shadowed words in the AXB test also significantly influenced judgments. Degree of prior exposure to token words did not significantly influence judgments of imitation. Experiment 2 employed modified target tokens with extended voice onset times (VOTs). In addition to AXB tests, VOTs of response tokens were compared across baseline and shadowing conditions. The AXB tests revealed shadowed words to be better imitations of target tokens than baseline, without an influence of AXB presentation order. Differences between baseline and shadowing VOTs were greater when VOTs were extended. The implications of spontaneous imitation in nonsocial settings are considered.

Deterministic center of pressure patterns characterize postural instability in Parkinson's disease

Static posturographic recordings were obtained from six Parkinson’s patients and six age-matched, healthy control participants. The availability of vision and visuo-spatial cognitive load were manipulated. Postural sway patterns were analyzed using recurrence quantification analysis (RQA), which revealed differences in center of pressure (COP) dynamics between Parkinson’s and control participants. AP COP trajectories for the Parkinson’s group were not only significantly more variable than for the control group, but also exhibited distinct patterns of temporal dynamics. The visual manipulation did not differentially affect the two groups. No cognitive load effects were found. The results are generally consistent with the hypothesis that pathological physiological systems exhibit a tendency for less flexible, more deterministic dynamic patterns.

Cross recurrence quantification of coupled oscillators

Subtle nonlinear behaviors of fluid-coupled mechanical oscillators at low and medium viscosities were better detected by cross recurrence analysis than spectral analysis. Cross recurrence with its high sensitivity to nonlinear dynamics may have applicability to weakly coupled oscillators prevalent in biology and physiology.

Affordance, proper function, and the physical basis of perceived heaviness

The physical basis of perceived heaviness requires consideration of the haptic perceptual systems role in controlling actions (the systems proper function) and the relation of an objects inertial properties to properties of the human movement system (the objects affordance). We show that the mass of a wielded object and particular scalar variables calculated from the objects inertia tensor combine linearly in determining perceived heaviness. The tensor-derived scalars reflect the symmetry and volume of the corresponding inertia ellipsoid. These measures bear directly on the objects wieldability, that is, on the patterning and level of muscular forces required to move the object in a controlled fashion.

Concurrent Cognitive Task Modulates Coordination Dynamics

Does a concurrent cognitive task affect the dynamics of bimanual rhythmic coordination? In-phase coordination was performed under manipulations of phase detuning and movement frequency and either singly or in combination with an arithmetic task. Predicted direction-specific shifts in stable relative phase from 0° due to detuning and movement frequency were amplified by the cognitive task. Nonlinear cross-recurrence analysis suggested that this cognitive influence on the locations of the stable points or attractors of coordination entailed a magnification of attractor noise without a reduction in attractor strength. An approximation to these findings was achieved through parameter changes in a motion equation in relative phase. Results are discussed in terms of dual-task performance as limited resources, dynamics rather than chronometrics, and reparameterization rather than degradation.

Language Use, Coordination, and the Emergence of Cooperative Action

Over the last three decades, two major theoretical developments within cognitive science have enriched our understanding of perceptual function and coordinated action in real-world environments.

Attunement, calibration, and exploration in fast haptic perceptual learning.

Abstract Often, a relatively small number of trials suffices to enhance ones task-specific perceptual capability. In the present experiment, fast perceptual learning was investigated with respect to the perception of the heights or widths of wielded nonvisible rectangular objects. In that haptic perceptual task, inertial differences (mass and moments of inertia) are the basis for perceived size differences. The authors hypothesized that rapid improvement might occur in attunement (attending to the task-relevant inertial variable), calibration (scaling spatial extent to the task-relevant inertial variable), and exploratory behavior (wielding so as to differentiate the task-relevant inertial variable). Twenty-four students performed 25 trials with a set of practice objects; those trials were followed and preceded by 18 trials with a set of test objects. Practice, with knowledge of results (KR), improved both attunement, as measured by regression of perceived spatial extent on the inertial variables, and calibration, as measured by constant and variable error. Of the preceding measures, only variable error improved with practice in the absence of KR. In both KR conditions, however, exploratory behavior decreased in duration and complexity, as measured by recurrence quantification analysis. The present results suggest that the mechanisms involved in fast perceptual learning are more varied and complex than are those encompassed by current accounts.

Ecological Psychology: Six Principles for an Embodied–Embedded Approach to Behavior

Publisher Summary A truly embodied-embedded approach to behavior promises a radical change in how scientists conceptualize cognitive agents (both biological and nonbiological) and how they proceed to understand the behavioral order of such agents, both empirically and theoretically. This chapter views that cashing in the promissory note requires that perceiving, acting and knowing be studied as emergent properties of an organism (O)–environment (E) system. The six principles described in the present chapter are proposed as an appropriate framework for that study. It presumes that the persistent application of the principles should enable cognitive and psychological science to repay the many loans of intelligence thus far accrued.