Robert A. Hicks

Handedness and birth risk.

Abstract Based in part on a relationship he observed between the incidence of left-handedness and birth risk (defined by birth order) in male college students, Bakan has postulated that left-handedness is the result of neurological insult associated with pre-natal or delivery factors. The two replications which question Bakans hypothesis can be criticized as replications for suspected differences in each sample and because both failed to consider sex as a variable. When these variables were taken into account, no evidence of a relationship between left-handedness and birth risk was observed for male or female college students.

REM sleep deprivation diminishes fear in rats

Abstract To test the hypothesis that REM sleep deprivation decreases fear, the behavior of 44 rats was measured in an open-field test. Prior to this test, the animals were exposed to 4 days to one of four treatments, i.e., either a dry environment control, a wet environment control, a 2-day REM deprivation period, or a 4-day REM deprivation period. During the test both exploration and three parameters of emotionality were recorded. The results offered convincing evidence in support of the hypothesis.

REM sleep deprivation increases aggressiveness in male rats

Abstract As a test of the hypothesis that REM deprivation increases aggressiveness in rats, the effects of two and four days of REM deprivation were measured on the frequency and latency with which male rats attack mice. The results showed that REM deprivation increased the frequency of attacks, the muricide rate, and the latency to first attack in a “dose-related” fashion. To a degree these behaviors persisted through a 21-day recovery period.

STRIKING CHANGES IN THE SLEEP SATISFACTION OF UNIVERSITY STUDENTS OVER THE LAST TWO DECADES

Over two decades, our data document a substantial linear increase in the percentage of university students who self-reported dissatisfaction with their sleep, i.e., 24% in 1978, 53% in 1988, and 71% in 2000.

Handedness and Anxiety

The anxiety scores of 23 left-handed, 12 mixed-handed and 35 right-handed college students were compared with the result that right-handers were significantly less anxious then both the left and the mixed-handed groups (which did not differ statistically). Since these data appear to be unique, generalizations from them was thought to be premature.

Depriving rats of REM sleep: the identification of a methodological problem.

Several studies that used Jouvets platform-in-the-water technique to deprive rats of REM sleep are reviewed. It is observed that a consistent feature of the design of these studies was to ignore the ratio between the size of the animal and the diameter of the platform when the REM deprivation was manipulated. Some contradictory studies are considered, and it is shown that the discrepant outcomes in the literature could be the result of inattention to that ratio.

Correlation between handedness and birth order: compilation of five studies.

Bakan has suggested that left-handedness is the result of left hemispheric pyramidal motor dysfunction following perinatal hypoxia. To a degree support for the validity of this hypothesis rests on Bakans (1971, 1977a) findings that left-handed college students were more likely the progeny of birth orders designated as “high-risk” than right-handed students. Attempts by others to replicate Bakans data have been unsuccessful. To achieve a more powerful test of this relationship than has been provided by any single study, the data from the five studies which have considered it were pooled and tested. The resulting correlation between birth order and handedness was near zero.

Handedness and Accidents with Injury

As evidence for the hypothesis on the claim of reduced longevity for left-handers, Coren in 1989 reported data which suggested that left-handers were 1.89 times more likely to report injuries which required medical attention. This left-handed group included both left- and mixed-handed individuals. To clarify the results of his study, we repeated in part Corens study but defined handedness so that groups of right-, mixed-, and left-handed individuals were considered. In contrast to Corens data, we found that right- and left-handers did not differ significantly in the frequency with which they reported having experienced accidents with injury and that mixed-handers reported being significantly more likely to have had an injury-accident than either right- or left-handers. These data underscore the need to consider mixed-handedness as a separate group in studies of this type.

REM SLEEP DEPRIVATION AND PAIN THRESHOLDS IN RATS

The relationship between REM sleep deprivation and pain threshold was measured using 36 Sprague-Dawley female rats. Relative to that of the controls, a significant lowering of threshold to painful electrical stimulation was observed during each of the post-treatment tests, i.e., immediate, and after 3- and 24-hr. recovery periods, for the animals which had been REM deprived.

Pain Thresholds in Rats during Recovery from Rem Sleep Deprivation

Using 30 Sprague-Dawley female rats, threshold to pain was measured over the course of recovery from REM sleep deprivation. Relative to the untreated controls and to their own pretreatment thresholds, the REM-deprived animals showed significantly reduced pain thresholds which were still evident 96 hours after the termination of the REM deprivation. Possible implications of these data for research with analgesic drugs were noted.