Illusory Motion Perception Research Articles

Intraattribute and interattribute motion induction.

The phenomenon of motion induction occurs, for example, when a bar that is presented next to a spot, which itself was presented slightly earlier, is not correctly perceived to appear everywhere simultaneously, but seems to grow out of the spot. The spot is said to prime one end of the bar. Experiments have been designed to throw more light on the local and global aspects of this phenomenon, in particular to establish whether this illusory motion percept can be observed when the spot and the bar stimuli are defined with respect to the background by one of a variety of attributes, such as luminance, color, stereodepth (crossed and uncrossed), texture, and motion (start and stop). It was found that all attribute combinations supported motion induction readily, but that the strength of the perceived motion (as measured by magnitude estimation) varied and depended more on the attribute defining the bar than on the attribute of the spot. Luminance and color gave the most vivid effects, whereas motion and depth showed the least vivid effects. The influence of the amount of luminance and color contrast on the strength of the effect was also determined and it was found that these variables affected motion induction most at very low contrast levels close to detection threshold. It is concluded that the illusory motion in this effect depends only slightly on the particular visual attribute channel that carries the stimulus information. This is consistent with the contention that it is a high-level, attention-related effect, phenomenologically similar to polarized gamma movement.

Apparent movements induced by luminance modulations: a model study.

When the receptive-field profiles of the different units in the primary visual cortex are described by a series of different functions which are given by a Gaussian distribution and its first, second, and so on, spatial derivatives, a full analysis of the input-output processing of these units (under the assumption of linearity for small signals) can be achieved for a wide variety of optical stimuli consisting of closely adjacent fields modulated independently in intensity. Once the input-output relationship for one particular unit has been obtained, it is possible to calculate in a straightforward manner the spatial representation of the stimulus pattern in a two-dimensional distribution of such units. Investigations are reported into how a stimulus pattern (a dark or bright bar between two fields modulated in illuminance) is represented in a hierarchical structure of such layers of units, each layer containing just one type of receptive-field profile from the Gaussian family of derivatives. It is shown that if a visual percept is associated with the behaviour of the extrema or zero-crossings of the representations in the first few layers of such an architecture, a complete description can be given of the experimental results obtained by Gregory and Heard in their psychophysical experiments on illusory movement perception induced by luminance intensity modulations.

Neck muscle vibration modifies the representation of visual motion and direction in man.

The retinal coordinates of an image are normally insufficient to define the direction of an object in body-centred visual space. Gaze direction, specified by information on the position of eye-in-head and on the position of head-on-torso, is also required. While the source of the eye-in-head signal is controversial, it is clear that proprioceptive signals from neck muscles are sufficient to provide head-on-torso information. Observations by Goodwin et al., beginning in 1972, that vibration of limb muscles modifies proprioception from them, and induces illusory motion and false perception of limb position, suggested this study of the effects of neck muscle vibration on the representation of visual space. Verbal reports, supported by objective measures, revealed that vibration of muscles on one side of the neck induces a visual illusion: contralateral displacement of a small visual target viewed in the dark. Pointing movements towards the target are similarly affected, confirming that the representation of directions in visual space is modified by neck muscle vibration. A second vibration-induced illusion was uncovered when apparent displacement ceased. This is an illusion of pure target motion in the same direction as the previously observed displacement. The magnitudes of both the displacement and pure motion illusions were dependent on vibration amplitude and were unrelated to real or apparent movements of eyes or head. Taken together these observations indicate that vibration of neck muscles can modify independently (1) the central representation of the instantaneous direction of gaze and (2) the signal of the velocity with which this direction is changing.

The Ames window illusion: perception of illusory motion by human infants.

The sensitivity of human infants, 5 1/2-9 months of age, to the illusory oscillation of the Ames window was assessed in three experiments that employed some variant of the habituation-dishabituation and forced-choice preferential looking paradigms. In Experiment 1, three groups--5 1/2, 7 1/2, and 9 months of age--were given a visual choice between rotating rectangular and Ames windows after exposure to a rotating circular form. The two older groups preferred the Ames window. The results of Experiment 2 showed that this preference is not based on structural differences between the two windows. In Experiment 3, familiarization with an Ames window produced a preference for rotary motion while familiarization with a rectangular window produced a preference for oscillatory motion. These results suggest that sensitivity to the illusion emerges around 7 1/2 months of age, an outcome consistent with the emergence, at this time, of sensitivity to pictorial cues to depth.

The Ames window illusion: Perception of illusory motion by human infants.

The Ames window illusion: Perception of illusory motion by human infants.

Perception of illusory movement.

Intensive studies of visual illusion have rarely shown examples of polymorphic responses. We show here that, using figures consisting of stripes shaded from dark to light, arranged in repeating sectors, an illusion of movement can be induced in about 75% of observers when viewed peripherally. The responses of the viewers fall into four categories. This polymorphic response suggests a genetic origin.

The illusory perception of movement caused by angular acceleration and by centrifugal force during flight. II. Visually perceived motion and displacement of a fixed target during turns.

oculo-gyral and oculo-gravic illusions were studied in flight using three Ss who observed a fixed luminous target in the dark. The observations were made in the rear cockpit of an SNJ-6 aircraft while the pilot executed turns with different degrees of bank… . In the first series the turns were carried out by using a constant power setting and changing the angle of attack of the wing to maintain the proper altitude. In the second series the angle of attack was held constant while the power was increased to maintain altitude. The third series was a repetition of the first for 3 selected angles of bank… . there was no significant evidence of any difference in the illusory perceptions during the 2 types of banks nor was there any evidence of habituation within the limits of this experiment. The illusory motion and displacement upward occurred at all angles of bank studied. There was a clear positive relation between the accelerative forces and the occurrence of the illusions. There was also an increase in the magnitude and duration of the illusions observed as the accelerative forces increased. (PsycINFO Database Record (c) 2012 APA, all rights reserved)

The illusory perception of movement caused by angular acceleration and by centrifugal force during flight. I. Methodology and preliminary results.

Abstract : Experiments were carried out on three subjects using five basic maneuvers in addition to control periods of straight and level flight. It was shown that angular acceleration and g during flight induce illusory perceptions of motion and displacement of an objectively motionless object. The magnitude of the illusory effects may be great, the fixation object appearing to be displaced as much as 60 degrees from its actual position. The significance of this finding for aviation is evident. The method is adaptable to a number of types of studies concerned with the influence of angular acceleration and g on visual perception. (Author)

The Illusory Perception of Movement on the Skin

The Illusory Perception of Movement on the Skin