David Koulack

Recognition Memory, Sleep and Circadian Rhythms

In Experiment 1, subjects learned a list of words and were tested for recognition of them 24 hours later. For the delayed sleep group, learning was followed by a period of wakefulness; for the immediate sleep group, it was followed by a period of sleep. Retention was significantly better for the immediate sleep group, consistent with the notion that consolidation is enhanced by the interpolation of sleep shortly after learning. In Experiment 2, subjects were tested approximately eight hours after learning. The normal waking group learned and was tested after a period of daytime weakfulness; the normal sleep group learned and was tested after a period of nighttime sleep; and the sleep deprivation group learned and was tested after a period of nighttime wakefulness. Retention for the normal sleep group was superior to that of the normal waking group, thus extending the commonly observed effect of sleep on memory to the domain of recognition memory. However, we found that retention was not better for the normal sleep group than for the sleep deprivation group suggesting that the effect of sleep on memory may be partially due to circadian rhythms.

RECOGNITION MEMORY, CIRCADIAN RHYTHMS, AND SLEEP '

One set of 20 subjects learned a list of words early in the morning while another set of 20 learned the same material in the midafternoon. Half of the subjects (n=10) were tested after an intervening four hours of sleep, while the other 10 were tested after four hours of waking activity. Subjects in the afternoon groups performed better on a recognition task than those in the morning groups, while subjects who had intervening periods of sleep between learning and testing performed better than their counterparts who remained awake. Finally, those subjects who learned in the afternoon and slept prior to testing did best on the recognition task, while those who learned in the morning and remained awake did worst. These results are consistent with the notion that both sleep and circadian rhythms play a role in the memory process.

SLEEP PARAMETERS OF TYPE A AND B SCORING COLLEGE STUDENTS

162 subjects, half of whom scored between 310 and 420 and half of whom scored between 184 and 256 on the Survey of Work Style questionnaire, participated in this study. The former group was defined as Type A scorers and the latter as Type B scorers. Type A scorers had more trouble falling asleep, had more nightmares, and spent less time asleep than did Type B scorers. However, there was no difference between the two groups in the amount of dream recall or on the morningness/eveningness continuum.

The effect of parental divorce on parent-adolescent separation.

The purpose of this study was to identify variables that differentially affect parent-adolescent separation in subjects from separated vs subjects from intact families. The subjects were 318 introductory psychology students at the University of Manitoba who had already left home. They were given the Moving Out questionnaire as well as Rotters Internal-External Locus of Control Scale. Contrary to our hypotheses, subjects from separated families did not experience more conflict when leaving home than subjects from intact families, and the type and amount of divorce-related conflict was not related to higher emotional separation or locus of control scores. However, it was found that as divorce-related conflict became more openly expressed, feelings of personal control increased and feelings about leaving home became more positive. Emotional separation scores were significantly higher for all males and for subjects from separated families. Also, females had a greater sense of external control than males.

Laboratory Sleep Patterns and Dream Content of Type A and B Scoring College Students

The suggestion that there may be a discrepancy between subjective and objective measures of sleep led us to explore the sleep and dreams of 7 Type A and 7 Type B scorers in our laboratory over a three-night period. In earlier studies, Type A scorers had indicated that their sleep was somewhat more disturbed and their dream content generally more active and negative in tone than that of Type B scorers. However, in this study the only differences were that Type A scorers had a greater number of body movements and greater dream recall than did Type B scorers. These results seem to indicate that the impression Type A scorers have of the quality of their sleep and dreams may be a function of their waking life-style.

A Rating System for Lucid Dream Content

Retrospective dream reports from 179 undergraduate students were scored by two independent raters in an attempt to assess the reliability of a newly-developed rating system for lucid dream content. The weighted Kappa statistic, which provides an index of chance-corrected interrater agreement for qualitative data, was used to assess the reliability of the ratings. The results indicated that the lucid dream rating system could be reliably used to identify different types of lucid dream content in dream reports, but some categories were less efficacious than others. Suggested revisions to the rating system are discussed.

Field dependence and the effect of REM deprivation on thirst.

Recently a number of studies have concerned the possible function of rapid eye movement (REM) sleep and the mastery of stress. The present study was designed to explore the possibility that REM sleep might play a function in reducing the potency of a stressful physiological stimulus, thirst, as well as the possibility that such a function might be specific to individuals falling at different points along the field-dependence dimension. While there was no difference between REM deprivation and non-REM awakening nights in subsequent morning thirst, there was a significant interaction between field dependence and night on morning thirst measures for 10 college students. These results are discussed in light of previous work on stylistic differences in dreaming and their possible role in adaptation to stress.

Acceptance and Rejection as a Function of Ethnicity and Belief Intensity

Summary One hundred forty-two white tenth-grade high school students served as Ss in a study designed to investigate the race-belief question with a Canadian analogue of black-white relations in the United States. In addition to ethnicity, the relative importance of belief to the respondent was examined. It was found that a minority group member was more accepted by the white majority than his majority group counterpart when they both expressed high intensity beliefs similar to those of the majority and that a minority group member was less rejected by the majority than a majority group member when they both expressed high intensity beliefs dissimilar to those of the majority. These findings were discussed in light of a number of other studies that suggest that disconfirmation of expectations is the crucial variable in altering social distance.

Decrease in field dependence following rapid eye movement sleep

Eight undergraduate males received the embedded figures test (EFT) on one of two testing nights in the laboratory and the rod and frame test (RFT) on the other night. Tests were presented at either the beginning or end of each of the first four rapid eye movement periods (REMPs). Test presentation nights and awakenings were counterbalanced. Performance on the RFT was better at the end of REMPs than at the onset, but a high (r = +.67), though not significant, correlation was found between REM density and decrement of performance on the RFT.