Postpartum and lactational estrus: a comparative analysis in rodentia

Virgin rodents exhibiting cycling estrus have traditionally been used for comparative studies of reproductive behavior. However estrus occurs in other life-history contexts, some of which differ from cycling estrus (CE) in that (a) the female is disposed to behave both maternally and sexually and (b) they result in litter overlap (i.e., the simultaneous gestation and lactation of two litters). In this report, two of these other modes of estrus are examined, with emphasis on their evolutionary and ecological implications. By means of a literature search of the order Rodentia, postpartum estrus (PPE) and lactational estrus (LE) were documented in 15 families, 71 genera, and 141 species. Analysis of these data showed that PPE and LE were nonrandomly distributed across taxa. They were statistically overrepresented in the family Cricetidae and underrepresented in squirrels (Sciuridae) and in pocket mice and kangaroo rats (Heteromyidae). Analysis of the phenotypes by which PPE and LE are achieved suggests important differences between them and CE in several parameters of female reproductive effort and breeding strategy, including maternal and copulatory behavior, optimal timing of litters, and hormonal control of heat and lactation.     

Smoking and academic performance

Smokers and nonsmokers were compared on three aspects of academic achievement. Although exactly the same percentage of smokers and nonsmokers passed the first-year university examination, smokers obtained significantly higher marks. Similarly, smokers achieved significantly higher marks in their final year examinations in comparison with nonsmokers. Finally, a comparison of the tutorial essay marks of the smokers and nonsmokers again showed that smokers obtained significantly higher marks than nonsmokers. These data are consistent with the idea that ambitious students adopt smoking in the belief that it will help them study and sustain concentration.     

A process recording for evaluating group psychotherapy training methods

This paper discusses an exploratory investigation concerned with the long range questions: How does group psychotherapy help patients? and How can psychiatry residency programs best train residents to treat patients in therapeutic groups? Group psychotherapy has come to be accepted in its own right as a decisive contribution to the study of and relief of emotional disorders. As a component of comprehensive psychiatric services it is indispensable. However, while its clinical value has been demonstrated, its scientific validity has not. A Group Process Inventory has been developed by the author and has been utilized for the past two years by psychiatric residents in recording the process of their therapeutic groups in a teaching hospital mental hygiene clinic. The preliminary use of this recording as a clinical-teaching instrument has proven effective. This inventory is being revised to serve as a research instrument.     

Active-interactional cotherapy

In the literature on cotherapy, little attention has been focused on maximizing the effectiveness of two therapists working in tandem with families and couples. While cotherapists may at times share their ideas and feelings with their clients, and after the therapeutic session exchange views between themselves, generally little interaction occurs between them during the session. In this paper, a case is presented for more active interactions between cotherapists during the session, in order to expedite and facilitate change and growth in their clients. Anecdotal examples are provided to illustrate the approach.     

The influence of flavor preexposure and test interval on conditioned taste aversions in the rat

The effects of flavor preexposure and test interval on conditioned taste aversions were examined in four experiments. In the first three experiments, prior experience with a flavor different from that used as a conditioned-stimulus (CS) produced attenuated aversions when testing occurred after a 1-day interval but not after a 21-day interval. Preexposure to the same stimulus used as a CS produced attenuated aversions at both 1- and 21-day intervals. In Experiment 4, a delay interval between flavor preexposure and conditioning eliminated the attenuating effect of preexposure, but only when different stimuli were used for preexposure and conditioning. These data could not be easily accounted for by contemporary interpretations of preexposure as an event that interferes with subsequent acquisition of a conditioned aversion. An alternative retrieval interference hypothesis was outlined.