Individual differences in pulse brightness perception.
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Discrimination Learning↗
Biomedical subjects
C J Owsley
Publications and source records attributed to C J Owsley.
Human aging and spatial vision.
The ability to see spatial structures of a wide range of sizes was measured for two groups of observers (mean ages, 18 and 73 years). All observers had good visual acuity. Although older and younger observers did not differ in ability to see targets with fine structure (high spatial frequencies), older observers were only one-third as sensitive to targets with coarse structure (low spatial frequencies) as were younger observers or to changes in criterion. Older observers were also less able than younger observers to see moving targets. The reduced sensitivity of the older observers may adversely affect routine perceptual activities, such as face recognition and visually guided postural behavior, that depend upon low spatial frequencies.
Adult↗
Detection of elasticity as an invariant property of objects by young infants.
Three-month-old infants were habituated to two different motions of deformation, presented 'live' with an object of sponge rubber. After habituation, one-third of the subjects was presented with a third deforming motion; one-third was presented with a rigid motion of the same object; and the other third was presented with a continuation of the habituation sequence. The group presented with a rigid motion dishabituated, exhibiting a sharp increase in looking time. The other two groups showed little or no increase. These results suggest that infants perceive elasticity of substance, in contrast to rigidity, as an invariant property of an object over different deforming motions.
Elasticity↗
Development of the perception of invariants: substance and shape.
Three experiments investigated the perception of substance and shape as invariant properties of objects by three-month-old infants. In experiment 1, infants were habituated to two differently shaped objects undergoing a rigid motion. After habituation of the infants, the objects were presented undergoing a different rigid motion, or undergoing a deforming motion, or undergoing the same rigid motion. Habituation was maintained to the new rigid motion, indicating that the two rigid motions were perceived as sharing an invariant property. Dishabituation, on the other hand, occurred when a deforming motion followed a rigid one. In experiment 2, infants were habituated to one shape undergoing two different rigid motions. After habituation, the shape was changed but the same two motions continued. Dishabituation occurred, compared to a group with no shape change, indicating that shape is distinguished as an invariant property over two rigid motions. In experiment 3, habituation to a shape undergoing two rigid motions was followed by a new shape presented motionless, or the same shape presented motionless. Cessation of motion did not prevent recognition of shape as invariant. Two properties of an object, substance and shape, thus appear to be detectable as invariant in an event sequence, an instance of "phenomenal doubling" at an early age.
Child Development↗