Subconfigurations of the human form in the perception of biological motion displays

doi:10.1016/S0001-6918(99)00028-1

Acta Psychologica

Volume 102, Issues 2–3, September 1999, Pages 293-318

https://doi.org/10.1016/S0001-6918(99)00028-1 Get rights and content

Abstract

We report four experiments examining processes that contribute to the perception of point-light displays of human locomotion. In three experiments, we employed a simultaneous masking paradigm to examine the visual system’s use of configural information in global analyses of biological motion displays. In the fourth experiment, we obtained descriptions of our stimulus displays from naive observers. Performance in both the detection and identification studies suggests that the visual system responded equivalently to figures exhibiting any organization of limbs that is consistent with the human form. Moreover, the subconfigurations best detected were also most likely to be described independently as depicting a human figure. Thus our findings provide evidence that the visual system can exploit characteristic subconfigurations of the human form in the perception of human locomotion.

Section snippets

Background and motivation

Human observers are particularly sensitive to human movement. For example, adults can rapidly perceive a human form in a display of discrete elements (commonly referred to as “point-lights” and illustrated in Fig. 1a) moving as if attached to the major joints of an otherwise invisible person (Johansson, 1973). Though no explicit contours, textures, or colors indicate the presence of a human form, the visual system is able to extract the structure of a human body from the motion of these

General methodological approach

Our aim in these studies was to examine the visual system’s use of configural information in the extraction of human structure from motion-carried information. Previous research Bertenthal and Pinto, 1994, McLeod et al., 1996, Thornton et al., 1998, Vaina et al., 1990 suggests that the perception of biological motion displays involves global or configural processing mechanisms that do not rely exclusively on unambiguous local motion analyses. To examine the operation of those global mechanisms,

Overview of current studies

The studies reported below examine the operation of visual processes that analyze the configural information contained in point-light displays of human locomotion. Do such processes exploit general structural properties, consistent with general structural accounts, or do they exploit specific characteristics of the human form in motion? Experiment 1 examined the first hypothesis and found general structural accounts inadequate. Our subsequent studies examined the second hypothesis in greater

Experiment 1 – Does the motion of limb extremities signal human locomotion?

Based on the failure of general structural analyses, Mather and his colleagues proposed that, in the perceptual organization and analysis of point-light figures, the visual system exploits structure and motion that are highly characteristic of human locomotion (Mather et al., 1992). In their investigations, they presented observers with a set of point-light figures from which they removed elements at different levels of the body’s hierarchical structure. Observers performed a direction

Experiment 2 – Is the relative location of limbs essential to the perception of human form?

The organization of limbs comprising a human or animal form is thought to be an important characteristic in the recognition of a figure. However, the importance of limb organization has been assumed, rather than tested, in most research programs. It is plausible that the visual analysis of human form relies on the presence of configural units extending over relatively small spatial extents. Individual limbs, for example, might provide the visual system with sufficient information to signal the

Experiment 3 – What subconfigurations are characteristic of human locomotion?

In the studies that follow, we sought to ascertain directly whether diagnostic characteristics of human locomotion might be exploited in the perception of biological motion displays. As discussed in the general introduction, dynamic limb symmetry and the structural framework provided by the principal axis of organization appear to be salient properties of human gait. We thus varied the presence of these properties to create exemplars of human figures. We reasoned that any hypothetical,

Experiment 4 – The identification of human movement

The outcomes of Experiments 2 and 3 suggest that the visual analysis of biological motion displays exploits characteristic subconfigurations of human locomotion that can not be reduced to a single feature or a computationally combined set of features. However, in the paradigm we employed in those studies, observers’ responses to the task or to the instructions may have influenced their performance. More specifically, the masking paradigm permits successful detection of a figure using minimally

General discussion

The principal aim of the current studies was to determine whether and how visual motion analyses might be specifically attuned to properties of human locomotion. Experiment 1 showed that limb extremities are not themselves indicative of human form, per se, as proposed by Mather et al. (1992). Instead, while the movements of the feet and hands may play a fundamental role in the perception of a walker's heading, such movements are not sufficient for the exquisite sensitivity with which observers

Acknowledgements

This work was funded by NEI grants 099310 and 12300 and NATO grant CRG970528. Some of the findings reported here were presented at the 1997 annual meeting of the Association for Research in Vision and Ophthalmology in Fort Lauderdale, FL and at the 1997 meeting on Object Perception and Memory in Philadelphia, PA. We thank Yahaira Padilla and Kim Parke for their help collecting and coding data. We are grateful to Gretchen Van de Walle for her critical feedback during the writing of this article

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Subconfigurations of the human form in the perception of biological motion displays

Abstract

Section snippets

Background and motivation

General methodological approach

Overview of current studies

Experiment 1 – Does the motion of limb extremities signal human locomotion?

Experiment 2 – Is the relative location of limbs essential to the perception of human form?

Experiment 3 – What subconfigurations are characteristic of human locomotion?

Experiment 4 – The identification of human movement

General discussion

Acknowledgements

Neuropsychologia

Cognitive Psychology

Cognitive Psychology

Acta Psychologica

Artificial Intelligence

The coordination and regulation of movements

Global processing of biological motions

Psychological Science

A program to generate synthetic walkers as dynamic point-light displays

Behaviour Research Methods & Instrumentation

Coding theory adapted to gait perception

Journal of Experimental Psychology: Human Perception and Performance

Masking the motions of human gait

Perception & Psychophysics

Similarity of structure and the profile of visual recognition defects: A comment on Gaffan and Heywood

Journal of Cognitive Neuroscience

Brain activity during observation of actions: Influence of action content and subject’s strategy

Brain

Action categories and the perception of biological motion

Perception

Rethinking innateness: A connectionist perspective on development

Patterns of co-occurrence among the associative agnosias: Implications for visual object recognition

Cognitive Neuropsychology

A computational model of semantic memory impairment: Modality specificity and emergent category specificity

Journal of Experimental Psychology: General

A spurious category-specific visual agnosia for living things in normal human and nonhuman primates

Journal of Cognitive Neuroscience

The interpretation of biological motion

Biological Cybernetics

Visual perception of biological motion and a model for its analysis

Perception & Psychophysics

Spatio-temporal differentiation and integration in visual motion perception

Psychological Review

Beyond modularity: A developmental perspective on Cognitive Science

Processing integral dimensions: The whole view

Journal of Experimental Psychology: Human Perception and Performance