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Biomedical subjects

A H Reinhardt-Rutland

Publications and source records attributed to A H Reinhardt-Rutland.

At least 37 records · Page 2Linked to original sources
PubMed1995

On the possible causal relation between perceived spatial orientation and induced motion.

In 1994 Brooks and Sherrick showed that both the rod-and-frame effect and frame-and-spot-induced motion increase as the inducing frame is made larger. This suggests that change in perceived spatial orientation causes induced motion. Here it is argued that the rod-and-frame effect is more appropriately compared with induced rotation, which differs from frame-and-spot-induced motion in a number of ways. It is argued that the rod-and-frame effect may inhibit induced rotation.

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PubMed1994

Perception of motion in depth from luminous rotating spirals: directional asymmetries during and after rotation.

Motion aftereffect (MAE) following spiral rotation is often asymmetrical: centrifugal MAE exceeds centripetal MAE. Pronounced MAE asymmetry has been reported for conditions--especially with a minimal background pattern--promoting perception of motion in depth. Such conditions are predicted to elicit motion asymmetry during adaptation. In the present study observers viewed luminous spirals monocularly in the dark; they timed, and scaled for convincingness, motion in depth during and after rotation. Motion in depth during rotation was often almost continuous, but recession was more convincing than was approach. Approaching MAE lasted longer and was more convincing than was receding MAE: the duration difference was more pronounced than has been found in other MAE studies, corroborating the link between MAE asymmetry and motion in depth. A possible line of explanation resides in comparing spiral motion in depth with real motion in depth of objects: in particular, the rapid visual change and collision with the observer that characterises real approach of an object is lacking in spiral approach. Interspecies differences for 'looming' and MAE are discussed.

Adult↗
PubMed1993

Perceiving surface orientation: pictorial information based on rectangularity can be overriden during observer motion.

Although the observer's motion can elicit perception of relative depth, it is less successful in doing so when competing pictorial information is available. However, the evidence for this may be affected by limited extents of motion and by equidistance tendencies. Results obtained when monocular observers judged the orientation-in-depth of trapezoidal and of rectangular surfaces, during lateral head motion of extents 0 cm to 30 cm, are described. When the motion extent was less than 30 cm, trapezoidal surfaces were misperceived because they were interpreted as rectangular; this pictorial information was overriden only when the motion extent was 30 cm. The results may reflect the sequential nature of motion information and the redundancy of information in normal viewing: pictorial information may take precedence when motion is limited, but motion information can be indefinitely augmented. Comments are directed to: (i) the use of Ames 'distorted rooms' in this area of research, and (ii) the 'ecological' interpretation of pictorial information.

Adult↗
PubMed1993

Detecting slant-in-depth of real trapezoidal and rectangular surfaces: moving-monocular viewing equivalent to stationary-binocular viewing.

Cues from binocularity and observer motion are often believed to be more important in perceiving depth than pictorial cues such as relative visual size and linear perspective. Both binocularity and motion are effective in simulated displays. However, for real stimuli evincing nonveridical pictorial cues, binocularity has been more effective than motion; sometimes motion has had an insignificant effect. This may reflect inadequate extent of motion, an assertion investigated in the present study. Two groups of observers determined whether rectangular and trapezoidal surfaces were slanted-in-depth under stationary-monocular (SM), stationary-binocular (SB), and moving-monocular conditions with 15-cm (15MM) and 25-cm (25MM) lateral head-motion extents according to group. The trapezoidal surfaces appeared as rectangular during SM viewing to mislead regarding slant. The effect of pictorial cues was substantially diminished during SB viewing whereas 15MM viewing was weak, 25MM was as effective as SB viewing. Comparison of the overall numbers of correct responses for the two groups indicated no contextual biasing.

Adult↗
PubMed1992

Primary depth cues and background pattern in the portrayal of slant.

A rectangularity postulate has been used in algorithms for the purpose of interpreting two-dimensional representations of rectilinear objects. This rectangularity postulate may affect the perception of true surfaces. In this study, rectangular surfaces and trapezoidal surfaces--the latter simulating the horizontal slant-in-depth of the rectangular surfaces--were viewed under static-monocular, moving-monocular, and static-binocular conditions, both with and without a background pattern. The static-binocular condition elicited the greatest number of accurate responses. The moving-monocular condition did not elicit significantly more accurate responses than the static-monocular viewing condition did. The effect of background pattern was insignificant. These results were unexpected in terms of ecological validity and (regarding moving-monocular viewing) because of the importance of the role of relative visual motion in the detection of object motion. However, the results are consistent with the perception of depth separation of two discrete objects.

Adult↗
PubMed1992

Changing-loudness aftereffect following simulated movement: implications for channel hypotheses concerning sound level change and movement.

Listening to a tone changing unidirectionally in sound level causes an illusion of changing loudness in a steady tone afterward. This aftereffect may indicate channels for detecting the feature of change in sound level, which would primarily concern dynamic sound localization. Three subjects, one of whom was the author, participated in this study. The author predicted that opposite adaptation of the ears (the adapting stimulus is heard to move from one ear to the other) should lead to a movement aftereffect. This was not reported by the subjects. However, the subjects did report a changing-loudness aftereffect in a monaural test stimulus, and the characteristics of the changing-loudness aftereffect (such as its magnitude) were consistent with previous data, suggesting a two-stage channel hypothesis: Output from channels for several features, including sound-level change, simultaneously stimulate movement channels.

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PubMed1991

On the salience of the inducer's displacement in induced rotary movement.

It has been reported that an annulus patterned with two equally-spaced radial lines elicits slower induced rotary movement than an annulus patterned with sixteen equally-spaced radial lines. This has been attributed to the quantity of inducing stimulation. However, the number of pattern elements also affects the time course of induced rotary movement: it can be intermittent with two-radii inducers, but persistent with sixteen-radii inducers. Displacement of a two-radii inducer may be more salient to the subject than displacement of a sixteen-radii inducer: from time to time the displacement of the former may come to dominate perception, suppressing induced movement. Hypotheses invoking quantity of stimulation and salience of inducer displacement were tested by way of inducers with different numbers and spacings of pattern elements. Subjects timed induced rotary movement (experiment 1) and a subsequent aftereffect (experiment 2). The results were consistent with both the quantity of stimulation (experiments 1 and 2) and the salience of inducer displacement (experiment 2) having an effect. This suggests that at least two mechanisms may be involved in induced rotary movement.

Adult↗
PubMed1991

Induced rotary movement during eye movements: displays with unequal spacing of pattern.

In my previous (Reinhardt-Rutland, 1982) study, I suggested that eye movements enhance induced rotary movement. However, low salience of absolute displacement might also explain the results, as displays were covered with large numbers of equally spaced radial pattern elements. To test these competing hypotheses in the present study, I used an unequally spaced pattern in two displays. Common to each display was an annulus: In one display, the common annulus surrounded a disk, and in the other display the common annulus was surrounded by another annulus. In any trial, one component rotated and the other was stationary while for 40 s the subject's eyes followed a circular path concentric with the display; subjects timed those occasions when perceived stronger rotation resided in the common annulus. Despite an unequally spaced pattern, absolute displacement had a barely significant effect. Instead, perceived stronger rotation mostly resided in a display's more central component. I concluded therefore that eye movements enhance induced rotary movement.

Adult↗
PubMed1991

Spatial-contrast movement aftereffect can be rotary: support for link with aftereffect of induced movement.

The procedure for eliciting movement aftereffect (MAE) involves the subject's adapting to visual movement that subsequently stops. Conventionally, MAE is confined to the area of movement adaptation. However, Wohlgemuth (1911) demonstrated the existence of a type of MAE that had the opposite characteristics of an adjoining conventional MAE; the test area was unpatterned during adaptation and patterned during testing. This spatial-contrast MAE may be connected with the more recently identified induced movement MAE. Unfortunately, the eliciting movements have not necessarily been comparable; Wohlgemuth used centrifugal and centripetal movement, whereas induced movement MAE has generally been rotary. The results of this study indicate that rotary spatial-contrast MAE can be elicited by a display that, with modification, also elicits induced movement MAE and that the rotary spatial-contrast MAE is weaker than the equivalent induced movement MAE.

Adult↗
PubMed1991

Induced movement-in-depth and induced changing-size elicited by a luminous rotating spiral.

Induced movement-in-depth and induced changing-size are infrequently investigated forms of a phenomenon whereby movement is ascribed to a stationary stimulus. The present note concerns qualitative responses to a display designed to elicit both forms. The inducer was a two-arm luminous rotating linear-function spiral, and the stationary stimulus was an annulus concentric with the spiral; it was patterned with concentric luminous circles. Viewing was monocular. Among the findings, induced movement-in-depth was more frequently reported than induced changing-size, despite the lack of veridical movement-in-depth in the display. Possible lines of explanation are suggested.

Adult↗
PubMed1991

Does intermittence in induced rotary movement have any explanatory significance?

Induced rotary movement has been reported to start and stop repeatedly during 1 min of observation. This has been taken as evidence for the involvement either of cyclorotational optokinetic nystagmus or of roll vection. Both assertions are dubious. Regarding cyclorotational optokinetic nystagmus, available evidence shows that it is too weak to be important in induced rotary movement. Also, induced rotary movement and cyclorotational optokinetic nystagmus are affected differently by the velocity of eliciting stimulation. Regarding roll vection, the conditions for its intermittence do not match those for induced rotary movement. Also, although aftereffects for induced rotary movement are negative, those for roll vection are positive and negative. Intermittence in induced rotary movement may be parsimoniously explained as characteristic of a weak effect.

Eye Movements↗
PubMed1990

Aftereffect arising from unidirectional change of sound level in a tone: frequency specificity with a complex adaptor.

Subjects adapted to square-wave adaptors, stimuli containing odd harmonics of the fundamental, and, to provide baseline data, sinusoidal adaptors matching the square-wave's fundamental. Nulls were obtained for various frequencies of the test stimulus. At any given frequency, the baseline null was subtracted from the null for square-wave adaptation. These corrected nulls indicated frequency-specific aftereffects at the third and fifth harmonics. The evidence is consistent with previous attempts to link the aftereffect of changing sound level in a tone with the auditory movement aftereffect because the latter may also show frequency specificity.

Adult↗
PubMed1990

Detecting orientation of a surface: the rectangularity postulate and primary depth cues.

Computational metaphors for determining the orientation of planar surfaces represented in line drawings have exploited a postulate that often surfaces are rectangular. Previous research implies that people follow such logic with real surfaces in ecological viewing. However, this research is problematic methodologically and some research does not directly address the issue. The stimuli used in this study were rectangular and trapezoidal; the latter shape was used to mislead with regard to orientation under the rectangularity postulate. Viewing conditions were monocular and binocular, with and without observer movement. The results suggest that the rectangularity postulate was important under stationary monocular viewing but diminished with movement and was not apparent during binocular viewing. General arguments about the importance of secondary depth cues in ecological viewing are developed.

Adult↗
PubMed1990

Note on aftereffect of unidirectional sound-level change with different durations of test stimulus.

Prolonged listening to unidirectional change of sound level in a tone can cause a steady tone afterwards to change in apparent loudness in the opposite direction. Subjectively the present aftereffect appears strong immediately after removal of the adaptor, becoming much weaker within a second or so. To confirm this, the aftereffect was measured by nulling with different durations of test stimulus changing steadily in sound level. As predicted, rate of change of sound level was greater for the shorter test stimuli. This suggests that aftereffect measurement by nulling may be best achieved with short test stimuli. However, responses to shorter test stimuli were generally more scattered.

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