Effects of altering outcome expectancies on pigeons' delayed conditional discrimination performance

An outcome-expectancy mediation theory of learning was tested in a series of transfer experiments with pigeons. The principal technique employed was a delayed two-choice conditional discrimination in which the subject's correct choice yielded a food reward on one kind of trial and a feedback tone on the other. According to the theory, this task engenders two-link mediational chains in that each conditional cue controls a particular outcome expectancy (S-E link) and the expectancy, in turn, cues a specific choice response (E-R link). Relative to the hypothetical mediators established by preceding training, transfer problems required either the same mediational chains, the alteration of one link in each chain, or the alteration of both links in both chains for optimal performance. The results of four separate transfer experiments confirmed detailed theoretical predictions, including that of an unusual nonmonotonic transfer effect. The relation of the present theory to earlier mediation theories is discussed.     

The influence of similarity between relevant and irrelevant information upon a complex identification task

This experiment sought answers to two questions: (1) Do increases in the similarity between relevant and irrelevant information present in visual stimulus patterns detrimentally influence the performance of a complex identification task, and (2) does the effect of such similarity interact with increasing amounts of irrelevant information? An analysis of the response latencies and errors indicated that identification of the relevant information in the stimulus patterns becomes significantly poorer with increasing similarity between relevant and irrelevant information and with increasing amounts of irrelevancy. The results also showed that the joint effect of similarity and irrelevancy produces a greater performance decrement than that associated with either variable alone. Practice on the task reduced the detrimental effects.     

Remembering words and how often they occurred in memory-impaired patients

Memory &; Cognition - The recent memory impairments in Korsakoff’s (KD), Huntington’s (HD), and Alzheimer’s (SDAT) diseases are qualitatively different from one another. All...     

Identifying the multi-risk family prenatally: Antecedent psychosocial factors and infant developmental trends

Little is known about the relationship between mother and infant within multiproblem, so-called “hard to reach” families. In an effort to understand factors contributing to problems in caring for the young children of these parents, a group of 47 families was recruited for study by the Clinical Infant Development Program of the National Institute of Mental Health. Serious social pathology was found within 75 percent of families. The lives of mothers in these families was marked by long term disruptions: 64 percent were from families characterized by recurring poverty and psychiatric illness, and 69 percent reported disruptions in parental care prior to age twelve, while more than two-thirds reported a history of being physically and/or sexually abused as children. More than 75 percent of this group of women presently showed psychiatric distress. Many of these women have difficulty in providing adequately for their young children and require innovative intervention programs in order to facilitate parenting.