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Results for “Discrimination Learning”

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At least 127 records · Page 7Linked to original sources
PubMed1978

Attentional changes during discrimination learning by retarded children.

Eight moderately retarded children were trained on a simultaneous two-choice discrimination problem and a series of discrimination-shift problems. The procedure required the subjects to perform overt observing responses to produce elements of the discriminative stimuli, making it possible to measure directly changes in attention to different aspects of stimuli during learning. The patterns of change in observing responses were generally in line with descriptions of attentional changes derived from two-process theories of discrimination learning; for example, the frequency of irrelevant observing responses was high during the presolution period during extradimensional shifts but was low during intradimensional shifts. Contrary to current theories, extradimensional shifts caused an immediate increase in irrelevant observing responses, and intradimensional shifts usually caused an increase in relevant observing responses. Subjects responded to later shift problems by initially increasing both relevant and irrelevant observing responses, then withholding irrelevant observing responses.

Adolescent↗
PubMed1992

Monkeys (Macaca fascicularis) with rhinal cortex ablations succeed in object discrimination learning despite 24-hr intertrial intervals and fail at matching to sample despite double sample presentations.

Six cynomolgus monkeys (Macaca fascicularis) learned preoperatively a set of 10 concurrent object discriminations with 24-hr intertrial intervals. Three then had the rhinal cortex removed bilaterally, whereas the other 3 remained as unoperated controls. The animals with ablations were impaired in reacquiring the preoperatively acquired set but subsequently learned without any impairment a new set of 10 discriminations that was presented in the same way. The monkeys with rhinal cortex ablations then failed to learn delayed matching to sample, with double sample presentations, in 510 trials, whereas the control animals learned this task in 270 trials on average. The results add to existing evidence that rhinal cortex ablation produces a severe impairment in visual short-term recognition memory and show for the first time that this impairment is accompanied by normal long-term discrimination learning ability.

Animals↗
PubMed1989

Unilateral periarcuate and posterior parietal lesions impair conditional position discrimination learning in the monkey.

Monkeys were trained on a conditional position discrimination in which the conditional cue was a light blinking at two distinct rates and the discriminanda (illuminated buttons) appeared in varying symmetrical positions of eccentricity. Unilateral arcuate, posterior parietal, or principal sulcus lesions were performed at criterion. The monkeys were tested to recovery when a homologous lesion was made contralaterally. The first of two analyses examined a period of 4 weeks following each lesion; the unit of analysis was lesions. The arcuate and parietal lesions produced impairments on both widely eccentric and central discriminanda locations; initially, virtually all responses were deflected to the ipsilateral side. There was significant improvement after the arcuate and parietal lesions from weeks 1 to 4. An analysis of total trials to criterion showed major deficits from the second arcuate and parietal lesions, with the arcuate lesion impairment being particularly severe. These results establish that a spatial concept of left vs right is seriously deranged by unilateral lesions of cortical association areas involved in spatial orientation and discrimination.

Animals↗