Studies in the Peripheral Retina: II. The Purkinje After-Image on the Near Foveal Area of the Retina

Although true second-order conditioning has, apparently, not previously been demonstrated in any American laboratory, it was found that by using electrodes implanted in the occipital sensory areas of hens, second-order limb responses could be readily established in approximately 33% of a group of 51 subjects developing first-order conditioned responses. In a number of subjects, the second-order responses remained stable for hundreds of trials and were highly resistant to extinction. Electrolytic damage at the sites of the cerebral reinforcing electrodes had no discernible effect on the stability of the second-order conditioned responses. They could also be evoked when direct current which temporally overlapped the cerebral conditioned stimuli was passed between or adjacent to the signal electrodes.     

Experimental Studies in Ocular Behavior: I. The Dodge Mirror-Recorder for Photographing Eye-Movements

Two experiments are reported concerning the effects of semantic encoding operations on the subsequent usefulness of interitem semantic relations in recall. These experiments employ the Mathews paradigm in which Ss first make judgments about the semantic relatedness of words presented in triplets and subsequently have their memory for the words tested. These experiments examine the effects of variations in interitem associative strength (Experiment 1), and task instructions and triplet order (Experiment 2). The results are discussed in terms of the general effects of the semantic judgment task on the encoding of task-relevant and task-irrelevant semantic attributes of words.     

Studies in olfactory acuity. I: Measurement of olfactory thresholds in the rat

The capacity of the rat to respond to olfactory cues has been studied in three experimental situations: (i) an elevated Y-maze, (ii) a rectangular choice apparatus in which extraneous environmental cues were present, and (iii) a circular choice apparatus from which such cues were either excluded or randomized.

No rat showed any sign of learning on the Y-maze even after extensive training and the application of electric shock as deterrent for error.

Some rats succeeded in performing an olfactory discrimination in the rectangular choice apparatus but learning was retarded, and in some cases inhibited, by the counter-influence of non-olfactory factors.

All rats readily learned an identical discrimination when shielded from such cues in the circular choice apparatus which provides a satisfactory medium both for training and for the study of olfactory acuity.

Differences in the behaviour of rats on these three types of apparatus suggest first, that the formation of learned habits based on olfaction depends on the close contiguity of stimulus and reward, and second that the sense of smell possesses weak orientating properties by comparison with those exerted by other modalities. The findings thus help to explain differences in the ease or di+culty uith which olfactory discriminations have been established by earlier workers.     

Studies of the cognitive representation of spatial relations: I. Overview

The present article reviews the major results and conclusions of two experiments on the mapping and planning of actual (campus buildings) and hypothetical (ideal town facilities) items in a two-dimensional space. Direct mapping (planning) techniques are preferred over the method of pair comparisons, especially in the case of the actual environment.     

Studies of Stereotypes: I. The Directionality and Uniformity of Responses to Stereotypes

Abstract

Cattell, R. B. Personality and Motivation: Structure and Measurement. New York: World Book, 1957. Reviewed by J. A. Radcliffe.     

Studies in the Expanded Word Association Test: I. Effects of Cerebral Dysfunction

The effects of cerebral dysfunction upon responses to the Expanded Word Association Test were studied among psychiatric patients. Psychiatric patients suffering from impairments in cerebral functioning showed significantly (p < .001) more blocking, multi-words and repetitions, irrespective of the type of stimulus word, than psychiatric patients judged free of such impairment. By weighing these variables with discriminant function coeficients it was possible to effectively discriminate between the groups, with only four misclassifications out of ninety patients. The results were discussed in relation to a previous experiment where similar findings had been obtained, and to the use of the test as a clinical tool.     

Studies in spatial learning. I. Orientation and the short-cut. 1946.

1. The original rough formulation of the expectancy theory is difficult to distinguish from the alternative stimulus-response doctrines. Part of this difficulty results from the fact that implicit in this rough formulation, is a definition of the matrix "x expects a goal at location L," which makes it equivalent to the matrix "x runs down the practiced path," when certain conditions are fulfilled. Because of this difficulty, we have rejected this definition. 2. We have suggested instead a definition of the matrix "x expects a goal at location L" which makes it equivalent to the matrix "x runs down the path which points directly to the location L," when certain conditions are fulfilled. 3. To determine whether rats will run down such a path, whenever the original path is blocked, we have run 56 female rats in a situation which conformed to these conditions. 4. Thirty-six percent of the rats chose the path which pointed directly towards the location of the goal. The remaining rats were distributed over the other paths in a chance fashion. 5. We have concluded (1) that rats do learn to expect goals in specific locations, (2) that there are important similarities between this behavior and human symbolic behavior, and (3) that these similarities justify our using the word 'expectation' as a name for the disposition to short-cut when the original patch is blocked.     

Studies of a Child. I

The authors examined the relationship between newborn neurobehavioral profiles and the characteristics of early mother-infant interaction in Nagasaki, Japan. The authors administered the Brazelton Neonatal Behavioral Assessment Scale (NBAS; T. B. Brazelton &; J. K. Nugent, 1995) in the newborn period and the Nursing Child Assessment Teaching Scale at 1 month (NCATS; G. Sumner &; A. Spietz, 1994). They administered the Perceived Stress Scale (S. Cohen, T. Kamarck, &; R. Mermelstein, 1983) as an index of maternal stress experienced over the past month. Lower irritability, higher stability in skin coloration, and lower tremulousness in the neonatal period were correlated with higher levels of maternal nurturing behaviors at 1 month. Birth weight and 2 NBAS range-of-state items (peak of excitement, irritability) predicted 31% of the variance in NCATS caregiver subscale score. The NBAS autonomic stability items (tremulousness, startles, lability of skin color) predicted 31% of the variance in the NCATS child subscale score. Perceived stress and maternal sociodemographic variables (education, income, age, parity) were not associated with child, caregiver, and total scores on the NCATS. The results suggested that lack of autonomic stability in Japanese neonates might serve as an early indicator of infant frailty, negative behavioral cues, and decreased maternal responsiveness.     

Studies in the Principles of Judgments and Attitudes: I. Two Basic Principles of Judgment

The psychological test performance of 10 seven-year-old boys from an isolated, rural Guatemalan village was compared with ratings of their intelligence made by 42 adult village members. The adults' judgments were found to correlate strongly with the children's performance on the Embedded Figures, Verbal Analogies, and Memory-for-Designs Tests.     

Brain Potential Studies of Perseveration: I. Perseveration Time to Light

In an effort to investigate the effects of attachment to the dominant culture and of developmental level on the self-concept, 62 male Lebanese-Americans of first, second, or third generation of residence in America completed two forms (questionnaire and adjective checklist) of an instrument designed to measure self-image disparity. A series of questions was used to measure extent of attachment to the Lebanese subculture, and a social competence index was employed as the measure of developmental level. No effects associated with self-image disparity emerged for generation of residence or developmental level. However, subjects who were strongly attached to the Lebanese culture showed less disparity on the questionnaire than those who were detached from it. Some support was provided for the developmental position, since Low Competence Ss made larger numbers of extreme responses on the questionnaire than the High Competence S.