Undernutrition by rearing in large litters delays the development of reflexive, locomotor, and memory processes in mice

In three experiments, the effects of early postnatal undernutrition on the ontogeny of several behavioral capacities of varying complexity were investigated in the mouse. Following birth, mouse pups in all experiments were reared in either "normally nourished" or "undernourished" conditions by maintaining litter sizes at 6 or 16, respectively. Experiments 1 and 2 examined the development of adultlike patterns of swimming behaviors and spontaneous locomotor activity, respectively, as a function of litter size. The maturation of both behavior patterns was delayed by about 2 days in the 16-litter mice. In Experiment 3, normally nourished and undernourished mice received 25 trials in a shock-escape T-maze at 9, 11, and 13 days of age, followed by similar retention tests 24 hr later. Although litter size had little effect upon correct turns at each age during training, mice reared in litters of six exhibited significant retention of prior training by 12 days of age, whereas comparable retention was not noted for the large litter mice until 14 days of age. Overall, these results suggest that nutritional deficits, imposed by rearing in large litters during the postnatal period of rapid central nervous system maturation, retard the development of behavioral capacities involving both unlearned and learned responses.     

Failure of additivity in bisection of length

Subjects were intructed to select one rod to lie halfway in length between two given rods. These bisection instructions imply an additive model in the subjective metric. However, the data were inherently nonadditive; the length of the bisector could be an increasing or a decreasing function of the length of one given rod, depending on the length of the other given rod. A convexity analysis and a nonmetric analysis both showed that no monotone transformation could make the data additive. The bisection problem is used to contrast the axiomatic and functional approaches to measurement theory.     

A note on occupational values of ninth grade students of 1958 as compared to 1970

The occupational values of a sample of 1958 ninth grade students were compared with those of a sample of ninth grade students in 1970. The overall order of rankings was similar, but some shifts did occur. These shifts suggest that 1958 ninth graders sought a stable enjoyable job, while the 1970 ninth graders hope for enjoyable work at high pay.     

Using computers in introductory psychology

This paper describes our experience during the past 2 years in establishing a computer-based laboratory for introductory psychology. Discussion includes selection of hardware; physical design of the laboratory; locating, reviewing, and selecting courseware; development of supplementary materials; operation and management of the laboratory; and integration of the laboratory into the curriculum. These factors are examined from the point of view of the decisions made, the difficulties encountered, and the lessons learned.     

COMPsych: A computerized software information system

This paper describes the development of COMPsych, a computerized system to disseminate information about software dealing with ail aspects of psychology. The need for such a service, the various components, and the general operation of the system are described. The system will contain a catalog of commercial and public domain software, a library of freeware, a directory of computer users, and a bulletin board.     

Tools for connectionist modeling: The dynamical systems methodology

Some understanding of dynamical systems is essential to achieving competency in connectionist models. This mathematical background can be acquired either through a rigorous set of upper undergraduate and/or graduate formal courses or via disciplined self-teaching. As part of developing a course in connectionism, we feel that although certain very basic mathematical tools are most appropriately learned in their “pure” form (i.e., from mathematics textbooks and courses), more advanced exposure to dynamical systems theory can be given in the context of an introduction to connectionism. Students thus learn to write connectionist simulations by first writing programs for simulating arbitrary dynamical systems, then using them to learn some aspects of dynamical systems in general by simulating some special cases, and finally applying this technique to connectionist models of increasing complexity.     

Behavioral obesity research: Where have all the single subjects gone?

Many recent reviews of the literature concerning behavioral treatments of obesity have concluded that behavioral methods have not been as successful in treating this problem as might have been predicted in the early years of behavior modification. Among the many potential reasons for this lack of success is the growing trend to utilize group statistical designs rather than single subject designs to examine the problem of obesity, in spite of the fact that single case methodology has provided the foundation for applied behavior analysis and behavior therapy. Several behavioral journals were surveyed to determine more precisely the trends in types of research strategies utilized in obesity studies. The potential relationship between research methodology and the development of effective treatments is discussed.     

Factor structure of Calhoun's Youth Suicide Scale

To assess the factor structure of Calhoun's Youth Suicide Scale (YSS), 191 consenting undergraduates in one sample and 240 consenting undergraduates in a second sample wee given the YSS during class. From the second sample, 152 subjects also took the YSS a second time about 1 month later. In the first sample, three factors, which accounted for 50.0% of the variance, emerged. They were: How the Parents were Viewed (in terms of psychological disturbance, likability, and blame); Expected Responses to the Bereaved Family (terms of tension and sympathy); and Empathy with Parents (whether the newspaper was viewed as correct in reporting the cause of death, how long parents were expected to grieve, and whether parents were expected to be liked). In the second sample, the same three factors emerged (accounting for 55.5% of the variance), with the exception of one item on Factor 3: expecting to like the parents. Congruence coefficients between the three factors in the two samples were .98, .94, and .78, respectively. Reliability correlations on individual items ranged from a low of .30 to a high of .61. These results indicate that the YSS is valid, stable, and moderately reliable for assessing reactions to youth suicide; thus, it would be a viable instrument for use in future research on reactions to suicide.     

Emotional responding following experimental manipulation of facial electromyographic activity

Increases in zygomatic electromyographic (EMG) responding have been reported during the imagination of positive affective scenes, and increases in corrugator EMG have been reported during negative affective scenes. Thirty female subjects were instructed to imagine three positive affective scenes and three negative affective scenes. During the initial imagination of each scene, the subject was told simply to imagine the situation. The subject then imagined the situation again and was instructed to enhance the muscle tension in one of two muscle groups (the zygomatic muscles for positive scenes and the corrugator muscle for negative scenes). The subject then imagined the scence a third time and was instructed to suppress the muscle tension in the same muscle group. The order of administration of enhancement and suppression trials was randomized for each scene. Subjects were given several trials to practice controlling both zygomatic and corrugator EMG. Feedback was available during the practice trials and during the enhancement and suppression trials of the experiment. Continuous monitoring of both zygomatic and corrugator EMG during the study indicated that subjects were successful in altering muscle tension in accord with the experimental instructions, and videotapes of subjects' faces indicated no overt changes in facial responding during imagination of the scenes. Subjects' ratings of emotional responding during each scene indicated that subjects experienced less enjoyment and more distress during positive affective trials in which they suppressed zygomatic EMG activity. The results are discussed in terms of the facial feedback hypothesis.