Sensitivity to low doses of ethanol and pentobarbital in mice selected for sensitivity to hypnotic doses of ethanol.

These experiments assessed sensitivity to low doses of ethanol and pentobarbital in mice that had been selectively bred with respect to ethanol sleep time (the length of time an animal remains on its back following a hypnotic dose of ethanol). The hypothesis under investigation was that short-sleep (SS) mice might be more sensitive than long-sleep (LS) mice to excitatory effects produced by low doses of depressants. In support of this hypothesis SS mice were more active in an open-field test after ethanol than were LS mice. The lines did not differ in performance on a rotating-rod apparatus after these same doses of ethanol, suggesting that the difference in open-field activity was not attributable to a greater impairment of locomotor activity in LS mice. A similar difference in the open-field activity of the selected lines was observed with pentobarbital.     

Differentiation of adolescent activity participation

The sex typing or lack of it among 133 adolescent activities was investigated. Twenty-seven percent (32) of the activities on an Adolescent Activity Questionnaire showed very clear participation differences for male and female adolescents (11 to 18 years old). The initial two factors extracted in a principal components factor analysis were easily interpreted as feminine and masculine activities. Discriminant function analysis of 15 items from the first three factors yielded an 8-item function on the basis of which every sample member was correctly classified as male or female. Masculine activities included more sports-related activities and activities dealing with mechanics and building, whereas feminine activities were domestic in nature and included more sedentary activities (e.g., reading, writing in diaries).     

Sentence comprehension following agenesis of the corpus callosum

The sentence comprehension skills of a 6-year-old girl with callosal agenesis were compared to skills of three other children matched for age and verbal IQ. Sentence-picture matching and acting out tasks were used with reversible active, passive, and center-embedded relative clause sentences. The acallosal subject showed a deficit in syntactic comprehension. The difficulty was due to a failure to assign correct semantic roles to some sentence forms, not to a lack of ability to discriminate among the sentence forms. The data are consistent with a previous report by M. Dennis (1977, In Topics in child neurology, pp. 189-212) that in acallosal subjects syntactic comprehension can be adversely affected. Because this acallosal subject is only 6 years old, follow-up studies will be needed to determine whether she eventually acquires normal syntactic skills.     

Choice among bets and revision of opinion

Ss estimated subjective probability (SP) on the basis of a sample in a hypothesis testing situation by choosing the subjectively optimal bet cat of a list and by stating verbal odds. In the choice among bets situation SP was inferred on the assumption of subjectively expected value maximization. Both estimates of SP were conservative compared with the theoretical prediction and did not differ significantly. This suggests that (a) utility had no distorting effect on the choice of the bet and (b) conservatism is not specifically bound to the use of special number scales or response sets.     

PSARP,a programmable signal and response processor

Experiments on perceptual-motor skills often ask for complex application of standard devices. Combinations of the usual electric or electronic instruments such as signal generators, simple time counters and response recorders cannot always be used to form a sufficiently flexible system for a particular set of experiments. In general, an apparatus specially built for a specific experiment does not satisfy the requirements of related investigations and the same device is seldom used again. This paper gives an outline of the principles of a flexible and programmable system which meets the requirements of a considerable number of variables. Some first applications of the system are described.     

Cognitive categories and memory span: I. Shifting between categories

Broadbent and Gregory's hypothesis that shifting selection between cognitive classes is at least inefficient is tested by varying the number of transitions from consonants to digits and back in a mixed list memory span situation. No orderly decrease is found as a function of the number of transitions, which renders the attention hypothesis unlikely. An alternative position in terms of interference theory could explain the data qualitatively. Tests of further predictions of this theory need first an estimate of the degree of difference between cognitive classes.