Temporal and spatial factors in gait perception that influence gender recognition

Abstract

Several temporal and spatial factors affect gender recognition of a walker when portrayed, without familiarity cues, as a dynamic point-light display. We demonstrate that, among temporal parameters, the duration of the dynamic stimulus. must be longer than 1.6 sec, but that 2.7 sec is fully adequate. Given the speed of our walkers, the recognition threshold appears to be roughly two step cycles. In addition, presentation rate of the stimulus must be near to normal, perhaps because nonnormal rates alter apparent gravity and obscure the normal relationship between output and conservation of energy. We demonstrate that, among spatial factors, the discreteness of the joint information must be maintained for accurate recognition. We go on to argue that it is the information about the shoulder and the hip of a walker that is of primary importance. Finally, inversion of the stimulus display produces the unexpected effect of reversing the apparent sex of most walkers. That is, when presented upside down, male walkers appear female and female walkers appear male.If one removes familiarity cues from a dynamic display, nothing is left for the viewer to perceive except formless relations projected over time. Yet these formless relations can yield rich and vivid percepts. This fact proves embarrassing for any view of form perception that relies exclusively on superficial features such as lines and angles. The present studies explore how formless relations that afford gender recognition in human walkers survive temporal and spatial distortion. Our goal is that through this type of study we can learn more about the nature of those relations and how they are perceived.For nearly a century researchers have attached points of light that glow in the dark to the limbs of walkers for the purposes of studying gait (see Bernstein, 1967). In fact, through this technique and others, human gait may be the most studied of all biological movement. Nevertheless, nearly all of this work has focused on how the movement is produced. Until the work of Johansson (1973Johansson ( , 1975Johansson ( , 1976, few have studied how that movement is perceived.Using a point-light technique developed by Johansson, we have begun to study various aspects of gait recognition. Previously, we had found that individuals can recognize themselves and others without familiarity cues from such a dynamic display (Cutting & Kozlowski, 1977). Next, we (Kozlowski & Cutting, 1977) determined that viewers could idenThis paper is based on the Master's thesis of the first author. This research was supported by a small research grant from Wesleyan University to each of the authors. We thank Robert J. White for his continued help, and Carol Fowler, Dennis Proffitt, and David Stier for instructive comments. Reprint requests should be sent to J. Cutting or L. Kozlowski, Department of Psychology, Wesleyan University, Middletown, Connecticut 06457.tify the gender of a walker from that display, but not from static tokens taken out of the dynamic sequences. Variations in walking s...

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