Radical shifts in perceived spatial relations can occur through the operation of the principle of sensory saltation. In the realm of cutaneous sensation, where it was first encountered, and also in some auditory and visual situations, any brief stimulus preceding a second one by no more than about 300 ms ...

A study is reported of the perception of random-dot two-frame apparent motion in which the durations of each exposure and the interstimulus interval between them were varied. The results are largely consistent with the rule that, for optimal motion detection, a portion of each exposure must fall within the same ...

The ability to report the direction of apparent motion when an array of random dots is displaced fails when the displacement exceeds a limiting value (dmax). We find that dmax increases rapidly with retinal eccentricity, in a manner different from spatial measures such as acuity which are believed to depend ...

Two spatially separated vertical bar stimuli briefly flashed in temporal sequence produced strong sensations of stroboscopic apparent motion; particularly at intermediate onset asynchronies. The sustained presence of two additional stationary vertical bars flanking the two movement-inducing bars during their presentation significantly decreased the rated magnitude of the sensation of stroboscopic ...

Null measurements given by cancelling forces, voltages, or whatever, are used in physics for gaining 'objectivity'--by avoiding 'subjective' perceptions; but, somewhat paradoxically, null methods can be useful for studying perception itself. Here we consider cancelling opposed movements for photometry with coloured lights, and some recent experiments, carried out with John ...

Not only translations and rotations, but also intriguing 'plastic deformations' are observed in apparent motion. What kinds of invariants does the visual system depend on during these transformations to determine that two figures of different shapes nevertheless represent the same object? Experiments are reported in which seven pairs of stimuli ...

A small square and a large triangle below it were presented in the first frame. These were switched off and replaced by a triangle alone in the second frame, shifted horizontally and upwards. The triangle appeared to move obliquely, as expected, but most observers also saw the square moving horizontally ...

Apparent motion of an illusory surface was produced by presenting two spatially separated illusory squares in an appropriately timed sequence. Control experiments showed that the effect arose from the illusory contours themselves and not from motion of the cut sectors on the discs. When a template of this movie was ...

In this study, we investigated the cooperative and non-cooperative models of stereopsis on apparent movement of the short-range process using spatial frequency filtered random-dot cinematograms. Our results showed that when spatial frequencies were below 4 cycles/degree, maximum displacement (dmax) was decreasing (linearly) with increasing mean frequencies, but at 4 cycles/degree ...

When moving a vertical black and white bar pattern horizontally across a T.V. screen there appears to exist a slant of the pattern depending on movement velocity. Subjects were asked to compensate this geometrical distortion by adjusting a potentiometer. Results show a clear difference between theoretical and actual data where ...

Is motion perception based on a local piecemeal analysis of the image or do 'global' effects also play an important role? Use was made of bistable apparent-motion displays in trying to answer this question. Two spots were flashed simultaneously on diagonally opposite corners of a 1 deg wide square and ...

The primary purpose of the studies presented was to determine whether stimulus displacement in random-dot cinematogram apparent motion should be measured in terms of relative or absolute distance, while taking into account the effect of number of displaced elements. Support for each measure has been reported in the literature (Braddick, ...

Patterns consisting of concentric rings, moving inwards and outwards are superimposed dichoptically and optically. In both conditions opponent patterns motions lead to apparent standstills for considerable periods. In a tentative model both the apparent standstills and the remaining pattern motions are described as by-products, resulting from pattern combinations rather than ...

Apparent motion was investigated as a stimulus for optokinetic nystagmus (OKN) and self-motion perception (vection). Apparent motion was stimulated by stroboscopically illuminating vertical stripes on the interior of a large drum that rotated about the observer at 20, 40 and 60 deg/sec. We determined threshold stroboscopic frequencies (f) for the ...

Two alternative schemes have been proposed for coding the local direction of stimulus motion in the visual image. The "sequence discrimination" scheme (e.g. Barlow H.B. and Levick W. R., J. Physiol., Lond. 178, 477-504, 1965) uses sequential change in stimulus position over time to infer movement direction; the "spatiotemporal derivative" ...

A modified method of right triangle was proposed to estimate curvature of binocular visual space, as the empirical relation between the physical and visual spaces. Four experiments were reported and three conclusions were drawn from the results: the locus of apparent equidistance lies between the physically equidistant curve and the ...

In living tissue, membrane-bound organelles, including mitochondria, move along parallel cytoplasmic pathways. Motion is directed and tends to be confined to a single path. Deviations from this single path motion are rare. When present, however, they tend to occur at points of intersection of cytoskeletal linear elements (LE). Such intersections ...

The waggon-wheel effect was studied by use of three wheels with different numbers of spokes (4, 8, 16) and a wide range of strobe temporal frequencies. The results obtained are discussed in terms of a model in which: (i) nearest-neighbour relationships predict the direction and speed of movement, (ii) persistence ...

An experiment is described in which a bistable motion display is shown in four combinations of monoptic and dichoptic viewing. When two triangles are replaced by one of them, one of two competing phenomena can be seen: local disappearance of the triangle that has not been replaced; a 3-D rotation ...

This experiment showed that phoria-induced displacement adds to or subtracts from prism-induced displacement. A near stimulus (25 cm) was apparently displaced more than the optical displacement when the base of a prism was out and less when the base was in. In contrast, a far stimulus (200 cm) was displaced ...

The Murchison and Allende chondrites contain up to 5 parts per million carbon that is enriched in carbon-13 by up to + 1100 per mil (the ratio of carbon-12 to carbon-13 is approximately 42, compared to 88 to 93 for terrestrial carbon). This "heavy" carbon is associated with neon-22 and ...

Observers viewed a CRT display which contained both real and apparent motion. When the apparent motion was in the same direction as the real motion, the strength of the apparent motion was enhanced. Real motion in the opposite direction completely cancelled apparent motion. However, the appearance of the real motion ...

Experiments by several investigators suggest that forms between inducing stimuli for apparent motion may deflect motion from a straight path. In an experiment in which a binocularly viewed object was sometimes positioned between the inducing dots, we discovered that the degree of curvature of the path that is most likely ...

The expansion and contraction of a display consisting of a stationary grating with a superimposed inclined line leads to the apparent rotation of the line. This phenomenon has been investigated in six experiments with the use of a television system with a motorized zoom lens to effect such transformations. The ...

The problem of how the visual system matches corresponding inputs from one instant to the next to produce the perception of motion has been experimentally examined. The specific concern was whether this correspondence problem is solved prior to the interpretation of three-dimensional distance. Observers judged the degree of apparent motion ...

Twelve subjects found the longest possible interstimulus interval (ISI) at which they perceived continuous apparent motion of one light instead of partial motion or succession between two lights. In the visual condition, two lights only were presented. In the bimodal conditions, binaurally presented tones were presented synchronously with the lights, ...

Sequential alternation between same-shaped stimuli differing in size (size ratio s) and orientation (angular difference v) produced a visual illusion of translation in depth and concurrent rotation. The minimum stimulus-onset asynchrony required for the appearance of a rigidly moving object was approximately a linearly increasing function of (s-1)/(s+1) for simple ...

This experiment was undertaken to investigate the effects of different types and velocities of apparent motion on the Visual Evoked Potential (VEP). Central (Cz) recording site VEPs were obtained from four males and three females under seven conditions. Significant differences in terms of amplitude and latencies were found between continuous ...

Subjects observed a briefly exposed square and set a variable square to match its size. In experiment 1 the square was black or white and was preceded or followed by a flash of light. The preceding adaptation field was complete darkness or an illuminated field. Marked underestimation of size occurred ...

Temporal limits of stroboscopic apparent motion in depth have been examined. For monocular viewing the limits are similar to those obtained for motion in the frontal plane, while those for binocular viewing are greatly narrowed. In another experiment the contraction in space over which apparent movement occurs was measured. The ...

Foster's two schemes with respect to preferred paths in visual apparent motion were tested in conditions in which large differences in orientations and symmetry between the inducing stimuli resulted in large differences in the predicted apparent motion paths. The results showed that under these conditions the measured apparent motion paths ...

Warren proposed that for apparent motion to be perceived between disparate shapes, the shapes must be identifiable as the same object. When disparate shapes are seen as different views of the same rigid form, they are called ecologically transformable. Ecological transformability seemed to be the crucial variable in Warren's results. ...

Previous reports of intermodal apparent motion claim that the various senses contribute to or are under the guidance of a single synthesizing or organizing system, a common sense, and that under proper circumstances the separate heteromodal stimuli may be combined into a novel perceptual object. Our first experiment suggests that ...

This study examined in 4 normal-hearing young adults the effects of motion of the sound source upon the accuracy of auditory localization. S controlled the initiation of the energizing of a small loudspeaker on a rotating boom overhead such that the initiation of a brief tonal pulse at .5 kc/s ...

The experiments reported here show that Korte's space-time invariance equation governing perception of apparent motion is limited to situations in which metric or apparent separation of targets define but a single interval of space. Variation in interstimulus intervals and metric separation of targets did not influence the perception of apparent ...

Apparent rotational motion was investigated in polygonal shapes ranging in rotational symmetry from random to self-identical under 180 degrees rotation. Observers adjusted the rate of alternation between two computer-displayed orientations of any given polygon to determine the point of breakdown of perceived rigid rotation between those two orientations. For asymmetric ...

As one progresses from the most primitive to the most derived frogs, one observes remarkable changes in that peculiarly amphibian auditory organ, the amphibian papilla. In all but the most primitive frog, the papilla comprises two patches with separate innervation and apparently corresponding to a spatial separation of frequency sensitivity ...

A display was devised for the purpose of studying the information afforded by kinetic optical occlusion (the progressive erasure and replacement of static elements within a display). A microcomputer generated a series of equally spaced light bars on a dark background. The first bar on the left was suddenly blanked ...

Using the performance criterion of "success time" it has been possible to investigate in detail the changing efficiency of the amalgamation process as both capsule length and amplitude of oscillation are varied. The most efficient amalgamation was obtained for a length:amplitude ratio between 0.5 and 1.3 over a range of ...

Using the magnitude estimation and production methods, the psychophysical function for very, very short visual extents was shown to be a straight line. The argument is made that the linearity of the psychophysical function is independent of past experience. Such a linear relation to plausibly due to the linearity of ...

The effect of incident light, its point of origin, and its magnitude on receptor orientation was determined. A non-invasive test of vision, the Stiles-Crawford Effect (SCE), was used to investigate retinal directional sensitivity and alignment. The simple act of monocular black patching for a period of three to five days ...

When a group of dots within a random-dot array is discontinuously displaced, it appears as a moving region perceptually segregated from its stationary surround. The spastial, temporal and other constraints governing this effect are markedly different from those classically found for the apparent motion of isolated stimulus elements. The random-dot ...

Temporal-order judgments were used to demonstrate that a later visual stimulus can delay the perception of an earlier one when the two stimuli together produce the phenomenon of metacontrast or of apparent motion. The perceptual delay is the same for movement and metacontrast and for one or two characters appearing ...

Further information concerning the nature of selective attention processes in schizophrenia was sought by examining selectivity in the region corresponding to the normal stationary visual field. Acute schizophrenic, chronic schizophrenic, and neurotic subjects were required to discriminate pairs of vertical columns of dots that varied in confusion value and in ...

Previous results on the perception of motion indicate that perceived motion paths cannot be explained solely in terms of simple feature-specific analyzers. This is particularly true of apparent (phi) motion. In this paper we develop a dynamic network, with simple filtering and summation properties, which can predict the geometric paths ...

The correspondence between line segments in apparent motion is shown to be affected by the similarity between them. Increase in orientation difference or in length ratio between lines in a competing motion configuration decreases the probability of perceived apparent motion between them. The results suggest the existence of a built-in ...

Timing in the visual field is regarded as an additive conjoint measurement structure, psychophysical extension of stimulus path as an extensive measurement structure. These two sets of postulates lead to the derivation of an essential maximum for velocity perception. Apparent phi motion perception under strictly stationary stimulus conditions is described ...

We present some results which indicate that the known spatiotemporal limits for apparent motion are consistent with the motion being sinusoidal or a result of filtering. Given this we investigated how two such motions interact as a function of their relative temporal phase differences. This was accomplished by inducing two ...

Two different perceptual confrontations produced by two different cues (sides that seem to twist and apparent levels of depth), which were thought to influence the perception of the degree of possibility of impossible torus figures, were examined in two experiments. In Experiment 1 it was found that net change in ...

A fundamental process underlying motion perception is the matching of corresponding elements in different views. In this correspondence process spatial separation between elements plays a major role. The relevant separation is shown by the current study to be the two-dimensional, uninterpreted distance, a finding that has an implication to the ...