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Results for “VISUAL PERCEPTION”

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At least 91 records · Page 5Linked to original sources
PubMed1999

Visual perception of human activity and gender in biological-motion displays by individuals with mental retardation.

By examining perception of biological-motion in three experiments, we investigated whether limitations in perceptual ability by individuals with mental retardation may extend to learning perceptual categories based on elements of actions. In two experiments individuals with mental retardation and age- and gender-matched controls reported gender and activity in randomly ordered point-light displays. In Experiment 2 decision times were measured and in Experiment 3, the effect of training with feedback on discriminating gender was assessed. Individuals with mental retardation identified walking, running, and stair-climbing without error but were less proficient in identifying throwing, had slower decision times for activity identification, and could not identify gender. For both groups feedback training improved gender identification in the short- and long-term. Improvements represented above-chance responding for the retarded group. Experimental outcomes are discussed in terms of capacity to classify perceptual stimuli as actions.

Adult↗
PubMed1985

Nonveridical factors of visual perception and close following on the road.

Close following on the road, identified as contributing to accidents, may be partly explained as an involuntary response to nonveridical perceptual factors. These factors concern (a) underestimation of the driver's own speed and (b) incorrect estimations of the distance away and speed of the vehicle ahead of the driver.

Automobile Driving↗
PubMed1995

Temporal factors in visual perception: a differential approach.

The tradition in sensory and perceptual psychology is not to pay much attention to individual differences but to focus almost exclusively on normative or generic processes. Nevertheless, consistent individual differences may exist in sensory and perceptual processes, just as they do in all other areas of human behavior where their existence has been investigated. A preliminary study was made of flicker fusion frequency, apparent movement, and three other perceptual tasks as differential measures. With one exception, Letter Search, all of the tests were psychophysical rather than cognitive. All had to do with time; that is, perceptual speed mattered in all of them. The analysis focused on reliability, in the sense of consistency from trial to trial. Four of the five tests showed good reliabilities in this sense, while the fifth was borderline. In one test, Bistable Stroboscopic Motion, the dependent measure, interstimulus interval, showed a consistent though shallow tendency to lengthen with practice. In the remaining four tests practice effects were largely confined to the first two administrations.

Adult↗
PubMed1993

Multistable visual perception induces a slow positive EEG wave.

Seven subjects observed a multistable pattern (stroboscopic alternative motion: SAM), and were instructed to press the button immediately after perceptual switching with the aim of detecting some neurophysiological parameters of EEG activity. Our results indicate that the EEG changes observed during multistable perception are similar to the family of event related potentials which we called perceptual switching related positivity. Furthermore, the frequency component of this potential has a similarity to the frequency content of stimulus locked P300.

Adult↗
PubMed1993

The indispensability of precollision kinematics in the visual perception of relative mass.

The visible kinematic pattern that occurs when objects collide contains information about the relative mass of the objects. Recently, Gilden and Proffitt (1989) have claimed that perceivers are limited to the use of simultaneous elemental cues and that therefore mass discrimination judgments are independent of whether the precollision epoch is visible or not. The present paper argues that their experimental results are irrelevant because crucial parameters were held constant, and that false conclusions were drawn because their data were not treated for what they are: threshold measurements obtained with the method of constant stimuli. Three experiments are reported, showing that a high level of performance is attainable only when the whole event is visible, and thus that the effective information is extended over time. In addition, modified PROBIT analysis was used to determine what information observers use when the precollision epoch is occluded. Analytically complex invariants, based on vector components in the abstract collision-axis system, proved to have the best fit to the data. Thus the elementaristic premises in Gilden and Proffitt's cue-heuristic model for relative mass perception are defeated.

Female↗