Theories of apparent motion

A perceptual phenomenon called apparent motion has been described as a paradox that challenges the notions of causality and temporal order. While the illusion has generated a passionate and often highly technical debate about the relationship between subjective experience and its objective description, no accounts so far have examined the possibility that the source of the paradox lies not in the mysterious workings of the brain but in the inadequacy of the reductionist explanation. Here, I suggest that the paradox is created by the deep estrangement between subjective and objective perspectives which has created two separate and conflicted worldviews. The illusion itself reflects a veridical perceptual experience, while its analytical explanation fails because it lacks the very qualities it is trying to account for. Although the proposed solution is controversial, it offers a simple and potentially far-reaching explanation for a long-standing problem in psychology and consciousness research.

Psychological Bulletin, 1989

Netherlands Journal of Psychology, 2008

An extended version of Von Holst and Mittelstaedt's model is used to illustrate that the visual perception of motion can be described in terms that are compatible with the relative nature of the physical concept of motion. The model concerns how we perceive object motion, not only during eye movements, but also during head and ego motion of the observer, and with the inclusion of a noise factor. Various rather counterintuitive illusions deriving from this view are described and some philosophical consequences as to how we perceive reality are discussed. (Netherlands Journal of Psychology, 64: rg12;.) Motion, stationarity, velocity and the direction of motion are relative concepts. physicists only discuss motion as relative to the frame of reference which defines that particular motion. We may drive at 1oo miles an hour (relative to the road), and at the same time remain stationary (relative to another car driving next to us at the same speed). If the other car moves faster than we do, we move backward relative to it, and when it moves slower we move forward relative to it, which illustrates that motion is a symmetrical concept. A moving relative to B physically means the same as B moving relative to A.

Oxford Handbooks Online, 2014

This article presents a selective overview of motion perception starting with its early philosophical underpinnings. Its role in Gestalt psychology is highlighted including the discovery of the relativity of motion perception and form-motion interactions. The use of reference frames in the computation of motion is illustrated with examples, leading to its current implications on non-retinotopic processing.

Visual apparent motion is the experience of motion from the successive stimulation of separate spatial locations. How spatial and temporal distances interact to determine the strength of apparent motion has been controversial. Some studies report space–time coupling: If we increase spatial or temporal distance between successive stimuli, we must also increase the other distance between them to maintain a constant strength of apparent motion (Korte's third law of motion). Other studies report space–time tradeoff: If we increase one of these distances, we must decrease the other to maintain a constant strength of apparent motion. In this article, we resolve the controversy. Starting from a normative theory of motion measurement and data on human spatiotemporal sensitivity, we conjecture that both coupling and tradeoff should occur, but at different speeds. We confirm the prediction in two experiments, using suprathreshold multistable apparent-motion displays called motion lattices. Our results show a smooth transition between the tradeoff and coupling as a function of speed: Tradeoff occurs at low speeds and coupling occurs at high speeds. From our data, we reconstruct the suprathreshold equivalence contours that are analogous to isosensitivity contours obtained at the threshold of visibility.

2013

This article discusses theories and evidence on the flow of time as a perceptual illusion. The flow of time is said to be a stubborn illusion, although it has never been experimentally verified. There is a high-level flow of time (the experiential phenomenon of the past, present, and future), as well as a low-level flow of time, happening, which includes spatial change (motion). The hypothesis is that the latter, happening, component of the flow of time is a perceptual illusion. Previous research reveals that motion perception occurs in discrete processing epochs, frames, or snapshots. Apparent motion is painted onto each snapshot, and motion is not experienced because of a change in position between two consecutive snapshots but is represented within a single snapshot. When people view video scenes of a walking man and toasting bread with a wide range of interstimulus intervals, fewer of them could "see it happening" as the intersthnulus interval was increased. This suggests that happening, whether involving a color change or a motion, is a frequency-dependent percept. It can be eliminated, for example, by choosing the appropriate stimulus frequency. TIle low-level component of the flow of time is therefore a perceptual illusion. Einstein said that "the past, present and future are only illusions, even if stubborn ones," that create a (false) impression that time is flowing (Davies, 2002, p. 41). However, no experimental evidence supports that contention. Before investi gating the hypothesis that the flow of time is an illusion, we shall examine what is meant by "flow of time," a phenomenon which has been discussed in detail by We gratefully acknowledge the advice of Stuart Anstls at the inception of this research project and again following completion of the manuscript. We are also grateful to Harry Foundalis, who provided important commentary and suggestions. This article is based on a plenary talk presented at the

Perception & Psychophysics, 2005

When a moving target vanishes abruptly, participants judge its final position as being ahead of its actual final position, in the direction of motion (representational momentum;. In the present study, we presented illusory motion and examined whether or not forward displacement was affected by the perceived direction and speed of the target. Experiments 1A and 1B showed that an illusory direction of movement of a target was perceived, and Experiment 2 showed that an illusory speed of a moving target was observed. However, neither the direction nor the magnitude of forward displacement was affected by these illusions. Therefore, it was suggested that the mechanism underlying forward displacement (or some extrapolation processing) uses different motion signals than does the perceptual mechanism.

Consciousness and Cognition, 2019

This paper situates an original model of reentrant oscillatory multiplexing within the philosophy of time consciousness to argue for an extensionalist theory of the specious present. I develop a detailed differential latency model of apparent motion to show how the ordinality of experiential content is isomorphic to the ordinality of relevant brain processes. I argue that the theory presented has resources to account for other key features of the specious present, including the representational discreteness between successive conscious moments as well as the phenomen-ological continuity between them. This work not only shows the plausibility of an extensionalist philosophical theory, it also illustrates the utility of differential latency views in squaring temporal illusions with empirically supported neurodynamics.

[1989] Proceedings. Workshop on Visual Motion, 1989

The existence of two separate mechanisms for the processing of apparent motion, the short and long range processes, as proposed by Braddick in 1974, has been analysed through many different psychophysical experiments. In particular the fact that for the short-range process there exists an upper bound for the spatial displacement and temporal interstimulus interval between sucessive stimulus presentations was confirmed by various of these experiments. In order to get a more formal understanding of these issues, we analyze the phenomenon of apparent motion from the point of view of a reconstruction problem. This allows us to use the sampling theorem to analyae the problem of temporal (spatial) reconstruction of uniformly translating patterns. In the case where the velocity field can only be extracted with uncertainty, it can be shown that there exists a maximum temporal (spatial) sampling interval, such that aliasing does not occur. We argue that, in the case of short-range process, due to its temporal (spatial) reconstruction ability, a similar effect could intervene in.the limitation of its activity to a small spatio-temporal scale.

Attention, Perception & Psychophysics, 2009

Motion perception usually is accompanied by the phenomenological impression of sequence as objects move through successions of locations. Nonetheless, there is accumulating evidence that sequential information is neither necessary nor sufficient for perceiving motion. It is shown here that apparent motion is specified by counterchange rather than sequence-that is, by co-occurring toward-and away-from-background changes at two spatial locations, regardless of whether the changes are simultaneous or sequential. Motion is perceived from the location of the toward to the location of the away change, even when the changes occur in reverse temporal order. It is not perceived for sequences of away or toward changes, as would be expected if motion were specified by onset or offset asynchronicity. Results previously attributed to onset and offset asynchrony are instead attributable to onsets and offsets occurring in close temporal proximity at the same location. This was consistent with units for detecting away and toward changes that are temporally biphasic; that is, they are excited by changes in one direction and inhibited by immediately preceding or immediately following changes in the opposite direction. These results are accounted for by a model for counterchange-specified motion entailing the biphasic detection of toward and away changes.