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Biomedical subjects

J Cerella

Publications and source records attributed to J Cerella.

7 recordsLinked to original sources
PubMed1991

Age effects may be global, not local: comment on Fisk and Rogers (1991)

A series of analyses of variance on target search times allowed Fisk and Rogers (1991) to reject the null hypothesis that age had a uniform, additive effect across search conditions. It does not, however, follow that age affected some conditions in an exceptional way, as Fisk and Rogers concluded. Age may have had a uniform but nonadditive effect across conditions. In this article, it is shown that age had a uniform linear, or perhaps slightly curvilinear, effect on search times. This "null hypothesis" adequately accounted for the age effects in all 27 search conditions. Indeed, it accounted for the age effects in 107 conditions abstracted from other visual search studied and for the age effects in 154 conditions abstracted from a miscellaneous collection of nonsearch processing-time studies. The only variation in age outcomes across studies was consistent with sampling error, given the known variance in response times. It is concluded that age is experienced as a generalized slowing of the central nervous system uniformly affecting all information processes.

Aged↗
PubMed1990

Pigeon pattern perception: limits on perspective invariance.

Two experiments are reported in which the response of pigeons to perspective transformations of a pattern target was measured. In the first experiment an alphabet letter was taken as the pattern target (the 'positive') and the response to its perspective transforms was compared to the response to nontarget letters ('negatives') over the course of discrimination training. In the second experiment irregular quadrilaterals were used as positives and the responses to slight perspective deformations of the prototypes were compared to the responses to random transformations of the same magnitude under steady-state conditions. The amount of differential responding depended on the type of transformation. There was no differential response to targets rotated in the picture plane or around the horizontal axis in either experiment. There was differential response to small reductions and enlargements of the target. There was also differential response to translated targets, and this was seen irrespective of the amount of displacement. Results from targets rotated around the vertical axis were erratic, some target-plus-angle combinations elicited differential responding, but most did not. The erratic responses are attributed to symmetries in pattern elements that were abstracted as critical features. Pigeons therefore exhibit no true rotation invariance, limited size invariance, and complete shift invariance. It is argued that size invariance, but not position invariance, may depend on prior exposure to the alternatives.

Animals↗
PubMed1987

Radial localization in the aged.

Elderly subjects were 41% less accurate than young subjects in localizing a point in the frontal plane. The decline could be ascribed neither to an age difference in image formation or skill acquisition nor to a difference in motivational level or trace retention. Evidently the "ambient" or "transient" visual system is compromised at an elementary level. Reasons why this deficit may not be compounded at more complex levels of spatial processing are suggested.

Adult↗
PubMed1986

Age differences in depicting and perceiving tridimensionality in simple line drawings.

Twelve young adults (M = 21 years) and twelve elderly adults (M = 67 years) were asked to draw a solid cube. The depictions produced by elderly adults were rated by judges as less accurate than the depictions produced by young adults. Both age groups were also asked to evaluate cube drawings that were deliberately distorted in ways characteristic of the depictions produced by older adults. Compared to younger participants, the elderly were more likely to accept distorted drawings as accurate. Control tasks demonstrated that older adults were able to draw and evaluate simpler two-dimensional patterns on par with younger adults. Apparently the mental representation of tridimensional information deteriorates with age leading to deficits in both production and recognition.

Adolescent↗
PubMed1985

Age-related decline in extrafoveal letter perception.

Peripheral vision is constricted in elderly adults. Experiment 1 showed that the age deficit in letter recognition time increased as the target moved off the fovea. Experiment 2 showed a corresponding reduction in angular threshold. Thus, the outer elements in a multicharacter display are seen with greater difficulty or not at all by the elderly adult. Experiment 3 showed this restricted field protected elderly adults from eccentric distractors, as found by Wright and Elias (1979). At the same time, elderly adults showed more, not less, interference on foils matched on discriminability with younger adults, in keeping with the larger literature on age and noise. Similar perceptual limitations may confound other array-processing experiments.

Adult↗
PubMed1979

Visual classes and natural categories in the pigeon.

After being trained on an oak leaf pattern, pigeons responded to other oak leaf patterns but not to leaf patterns of other species. Thus, graphic variation among the instances of a species is "transparent" to the visual system. At this taxonomic level, concept formation is spontaneous rather than inductive. It is argued that such immediate generalization may be critical to the survival of the organism.

Animals↗