On the relation between time and space in the visual discrimination of velocity.

Abstract

Is the perception of velocity determined by the prior discrimination of spatial and temporal distances? Two experiments sought to answer this question by comparing the discriminabilities of moving stimuli varied in spatial extent, temporal duration, or in redundant combinations of both variables. The subject's task was to identify which of two alternative stimuli was presented on each trial. A set of four stimuli was constructed from two values of spatial extent and two values of temporal duration. Separate conditions required discrimination of each of the six possible pairs of these stimuli. Experiment 1 examined continuous motion and Experiment 2 examined apparent motion for stimuli with short (50 versus 65 msec) and with long (500 versus 650 msec) interstimulus intervals. With continuous motion and with good apparent motion (short intervals), the discrimination between the different-velocity bivariate pairs was too accurate to be attributed only to discriminations of the spatial and temporal extents of the motion. This did not occur with poor apparent motion. Evidently, time and space are perceptually related.

Time, change, and motion: The effects of stimulus movement on temporal perception

“…A growing body ofliterature exists on the relation between time and motion, and includes such topics as velocity estimation (e.g., Algom & Cohen-Raz, 1984;Lappin, Bell, Harm, & Kottas, 1975;Tynan & Sekuler, 1982), time-of-arrival estimation (e.g., Cavallo & Laurent, 1988;Peterken, Brown, & Bowman, 1991;Schiff& Oldak, 1990), and motion detection (e.g., van Doorn & Koenderink, 1984;Verri, Girosi, & Torre, 1990). A number ofstudies have been concerned specifically with the perceived duration of moving stimuli.…”

Angular velocity discrimination

“…However, it may be the case that people are insensitive to angular dynamics simply because they lack the ability to perceive angular kinematics with any reasonable level of quantitative precision. Whereas there is a robust psychophysical literature on translational velocity perception (Lappin, Bell, Harm, & Kottas, 1975;McKee, 1981), little attention has been given to the perception of angular velocities. This is unfortunate since, in addition to the theoretical concerns listed above, rotational motions have several unique properties that can provide new insights into velocity perception.…”

The edge of an event: Invariants of a moving illusory contour

“…The perception of the motion-induced contour is similar, in this regard, to the perception of velocity, since both rely upon information which exists only within an integral space-time framework. In the discrimination of velocity, the perceptual relation between space and time has been shown for both continuous and apparent motion (Lappin et al, 1975). The present experiment tested the perceptual saliency of apparent motion in producing the motion-induced contour by including an object in apparent motion (ap- …”

“…For example, it has been shown that the perception of velocity is direct and not based upon independent discriminations of spatial and temporal extent (Lappin, Bell, Harm, & Kottas, 1975). The perception of the motion-induced contour is similar, in this regard, to the perception of velocity, since both rely upon information which exists only within an integral space-time framework.…”