Does reward depletion influence spatial memory performance?

If spatial memory tasks are considered as foraging problems, it can be predicted that rats' difficulty in learning a win-stay task—revisiting part of a maze where food has recently been found—should be partly overcome if the food is not fully consumed at the first visit (nondepleted reward) rather than being all eaten (depleted reward). Three experiments confirmed and further analysed this result. Experiments 1 and 2 showed that it does not depend on the amount of food initially found; nor is win-stay performance affected by the amount of food actually eaten. Experiment 3 suggested that the effects of nondepleted reward are mainly due to the animals' being interrupted while eating, and very little to the fact that uneaten food is left behind. The results are discussed with regard to their implications for learning theory, and for the application of foraging theory to learning and memory experiments.     

Perception of causal relations in humans: Factors affecting judgments of response-outcome contingencies under free-operant procedures

In three experiments, college studients responded to and rated a range of positive, random, and negative response-outcome contingencies presented in free-operant formats. These experiments sought a paradigm that would yield sensitive and unbiased judgments of response-outcome relations and explored the role of time in the judgment of response-outcome covariation. In Experiment 1, the effects of making continuous and discrete responses on subjects' contingency judgments were compared. In Experiment 2, the effects of changing the temporal definition of discrete responses were examined as were the effects of the amount of exposure to contingency problems. In Experiment 3, the effects of temporal regularity in defining response occurrence and nonoccurrence were investigated. In all three experiments, subjects' judgments were strong linear functions of the programmed contingencies between telegraph key operation and the illumination of a brief light. This result shows free-operant scheduling of response-outcome contingencies to be a highly sensitive and unbiased method of investigating causal perception. Additionally, judgment accuracy was found to be higher for males than for females and to improve as the probability of the subject's making a recorded response rose from .00 toward .50. Finally, a correlational analysis of several possible judgment rules supported the conclusion that subjects rated response-outcome relations on the basis of the difference in the probability of an outcome given their having recently made or not made a response.     

Pavlovian processes do mediate control of the “advance” response strategy

Two parallel experiments used pigeons in a transfer of control design to determine the basis of the transfer of the use of the “advance strategy” across successive discriminations (W. K. Honig & H. Lindsay, Learning and Motivation, 1975, 6, 157–178). Pigeons were first trained under instrumental contingencies to use an “advance” response to maximize their exposure to S^D and minimize their exposure to S^Δ. Then orthogonal stimuli (key lights in Experiment 1 and diffuse illuminations in Experiment 2) were independently established through separate discriminative Pavlovian procedures as CS+ and CS? or as CS^o's. Later in special tests, it was demonstrated that the associative values of the Pavlovian CS's were a major factor governing the use of the advance strategy: only pigeons exposed to $\text{CS+}\text{CS?}$ used the advance response to regulate their exposure to either CS. Although these experiments showed that the necessary and sufficient conditions for utilization of the advance strategy are the Pavlovian associative values of the discriminative stimuli, opportunity for differential “operant” responding during the discriminative stimuli seems to be a contributor to the optimal use of the advance response across successive discriminations.     

Written spelling deficit of Broca''s aphasics

The purpose of this study was to investigate the nature of the written spelling deficit manifested by Broca's aphasics. Four spelling tests were given to eight Broca's aphasic patients. Analysis of misspelling errors led the investigators to conclude that Broca's aphasics do not spell phonically, but rather adhere exclusively to a visual/orthographic strategy. Possible cognitive deficits underlying the spelling problem are identified. The written spelling deficit is related to other features of the syndrome of Broca's aphasia, and finally, speculations are offered concerning the neurological substrate of written spelling in Broca's aphasic patients.     

Inferential processing of context: Studies of cognitively impaired subjects

Language comprehension tasks involving pronoun coreference were administered to a group of demented patients, a group of patients with cardiac disease, and groups of normal elderly persons and young adults. Pronoun coreference was constrained by either lexical, syntactic, or contextual cues. No differences were found between old and young subjects for any task. While the demented patients were impaired on all tasks, the cardiac patients were specifically impaired in the inferential processing of context.     

The relationship of mathematics self-efficacy expectations to the selection of science-based college majors

The major purpose of the present study was to investigate the relationship of mathematics self-efficacy expectations to the selection of science-based majors in college males and females. Based on results obtained from a pilot sample of college students, an instrument assessing mathematics self-efficacy expectations was developed. The items used in the mathematics self-efficacy scale included everyday math tasks, math problems, and math-based college courses. Subjects, 153 female and 109 male undergraduates, completed the mathematics self-efficacy scale, the Bem Sex Role Inventory, an adapted version of the Fennema-Sherman Mathematics Attitudes Scales, and a questionnaire concerning their college major choices. Results indicated that mathematics self-efficacy expectations were significantly related to the extent to which students selected science-based college majors, thus supporting the postulated role of cognitive mediational factors in educational and career choice behavior. In addition, the math-related self-efficacy expectations of college males were significantly stronger than were those of college females. Implications of the findings for the process of educational and career decision-making are discussed.     

The role of duration and rapid temporal processing on the lateral perception of consonants and vowels

This study explored the extent to which rapid temporal processing and duration contribute to the right-ear advantage (REA) and presumably left-hemisphere processing for stop consonants and the lack of clear-cut laterality effects for vowels. Three sets of synthetic stimuli were constructed: consonant vowel stimuli [ba da ga bi di gi bu du gu] of 300 msec duration (full stimuli) and two shortened stimuli consisting either of a noise burst and 40-msec transitions (40-msec stimuli), or a noise burst and 20-msec transitions (20-msec stimuli). Stimuli were presented dichotically for consonant, vowel, and syllable identification. Results indicated a significant REA for consonants in the full and 40-msec conditions and a non-significant REA in the 20-msec condition. Nevertheless, the magnitude of laterality did not change across the three conditions. These results suggest that although transition information including duration contributes to lateralization for stop consonants, it is the presence of abrupt onsets which crucially determines lateralized processing. For vowels, there was a significant REA only in the full stimulus condition, and a significant decrement in the magnitude of the laterality effect in the two shortened stimulus conditions. These results suggest that for vowel perception, it is the nature of the acoustic cue used for phonetic identification and not duration that seems to be the critical determinant of lateralization effects.     

Mentally retarded individuals outperform college graduates in judging the nonconservation of space and perimeter

Most adults of average and superior intelligence incorrectly assume that in a two dimensional figure two attributes, area, and perimeter, are locked in a fixed relationship such that if one remains unchanged so does the other. Consequently, when they correctly conserve one attribute during shape transformation, they incorrectly conserve the other. Mentally retarded individuals assume no such fixed relationship but depend exclusively on perceptual information. Although this dependence adversely effects their judgment of conservation, it allows them to correctly judge the changed state of the nonconserved attribute.