Latent inhibition and stimulus generalization of the classically conditioned nictitating membrane response in rabbits (Oryctolagus cuniculus) following dorsal hippocampal ablation.

Rabbits received 0 to 450 exposures of a tone conditioned stimulus (CS) prior to classical defensive conditioning of the nicitating membrane response based on an infraorbital eye shock unconditioned stimulus. Tone preexposure resulted in retarded conditioning in normal rabbits. This latent inhibition effect was not present in animals with bilateral dorsal hippocampectomy produced by aspiration. Control animals with bilateral neocortical and callosal aspiration lesions demonstrated a latent inhibition effect similar to that shown by normal nonoperated animals. The failure of CS preexposure to retard conditioning in hippocampal rabbits was not due to differences in threshold of the conditioned response to the CS or to differences in response mechanisms as determined by tests of habituation and dishabituation of the unconditioned response. A subsequent experiment employed combined-cue summation tests to confirm the fact that preexposure did not endow the tone with conditioned as well as latent inhibitiory properties. Finally, tests of stimulus generalization along the auditory frequency dimension indicated flatter relative gradients for hippocampals than for nonoperated controls, with cortical controls in between. These findings were discussed in terms of Douglas' model of hippocampal function.     

Identification of tachistoscopically exposed symmetrical and asymmetrical letter arrays.

Six-letter arrays containing symmetrical, e.g., H, M, T, or asymmetrical letters, e.g., J, K, R, were tachistoscopically exposed bilaterally for 100 msec. to 100 college students. Significantly more asymmetrical than symmetrical letters were identified, and significantly more Ss identified more asymmetrical than symmetrical items. This experiment, which incorporated methodological considerations suggested by Harcum (1964) and Bryden (1968), corroborates their findings. Their ideas and other findings were used to account for the data. Asymmetrical letters have more intrinsic left-to-right directionality than symmetrical elements. The rapidly fading after-stimulation of tachistoscopically presented alphabetical material is usually scanned from left to right. Individual array letters might also be scanned in the same direction. Confluence of directionality of letter and scan, which obtains only with asymmetrical letters, might have typically allowed asymmetrical targets to be scanned more rapidly and, consequently, more efficiently than symmetrical displays.     

Perceptions of similarity between striving tasks and the generality of task preferences

Ninth graders rated their degree of liking for each of 12 striving tasks and, on another occasion, rated their perceptions of the similarity between each pair of tasks. Analyses of variance revealed strong PersonX Task interactions, suggesting the possibility of individual differences in task preference generality. A derived measure of task preference generality-specificity related significantly to an overall measure of perceived task similarity—generalizers saw the tasks as being more similar than did specifiers. Investigation of individual differences in degree of cross-situational generality was suggested as a way to integrate trait and situational theories of behavior.Data collection and initial data analyses for this study were conducted under the auspices of the Institute for Juvenile Research, Chicago, Illinois. Gratitude is expressed for the cooperation of the staffs and students at St. Michaels and Immaculata high schools, Chicago; for useful discussions of theoretical issues with Mark Oberlander; and for much assistance with data analysis provided by Arthur Kendall.     

Stimulus novelty and intraseries primacy in GSR adaptation

GSR records were obtained for four groups of 20 Ss. Group I was presented with a series of four different lights (amber, blue, green, and white) appearing 20 times each, in apparent random order. The procedure was similar for the other three groups except that in group 2, a novel stimulus (a red light) appeared instead of the sixth amber light; in group 3, it appeared instead of the 16th amber light; and, in group 4, it appeared instead of the 16th amber light. Typical GSR adaptation phenomena were observed in all groups. The introduction of the novel stimulus appeared to have no effect on the course of GSR adaptation.     

The Effects of Clarity of Decision Rule and Favorability of Verdict on Satisfaction with Resolution of Conflicts1

Favorability of outcome and clarity of decision rule were manipulated in a simulated conflict resolved by an impartial third party. Overall, subjects who received favorable outcomes were more satisfied than were those who received unfavorable outcomes. In addition, favorability of verdict and clarity of decision rule interacted in affecting overall satisfaction. Among subjects receiving an unfavorable verdict, those whose outcomes had been determined by a defined decision rule experienced greater satisfaction than those whose outcomes were based on an unclear, undefined rule. However, given a favorable outcome, the effects of clarity of decision rule were reversed-subjects reported greater satisfaction with the undefined than the defined rule. These results are discussed with reference to the particularism/universalism of defined and undefined decision rules.     

Effectiveness of students and parents in a psycho-educational intervention programme for children with learning problems

This study investigated the effects of involving two sources of ‘non-traditional manpower’ — namely, university students and parents — in a programme of psycho-educational intervention. It was predicted that, while intervention for children with learning problems would produce significant changes in their perceptions in relation to their families, in their scholastic skills and in their adjustment, the additional involvement of their parents would lead to even greater changes. To test this prediction, 36 children referred to a university Education Clinic were randomly divided into three equal-sized groups: youth counselling plus parent counselling (E₁), youth counselling (E₂), and a control group (C). While the hypothesised changes following intervention were not statistically demonstrated, clinical data did yield support for the effectiveness and potential value of the intervention programmes.