The role of propulsive muscles of the shoulder during quadrupedalism in vervet monkeys (Cercopithecus aethiops): implications for neural control of locomotion in primates

In comparative anatomical studies of the shoulder, the humeral retractors are often grouped together as propulsive muscles, which are important in the propulsive stroke of the forelimb during quadrupedal locomotion. Electromyographic (EMG) analyses of these muscles in opossums, cats, and dogs in general have confirmed such conclusions. An EMG study of chimpanzee shoulder muscles during knuckle-walking found, however, that the humeral retractors are either inactive or perform a function unrelated to propulsion (Larson & Stern, 1987). This contrast in muscle recruitment patterns between chimpanzees and more "typical" mammalian quadrupeds was attributed to the derived morphology of the chimpanzee shoulder. The present study examines the activity patterns of the humeral retractors in the vervet monkey, a primate more closely resembling nonprimate mammals in its shoulder morphology. The results of this EMG analysis show that despite the significant differences in anatomy between chimpanzees and vervets, the two species display very similar muscle recruitment patterns during quadrupedalism, and there is evidence for this same pattern in other species of primates. These differences in muscle activity patterns between primates and nonprimate mammals may be related to changes in the neurological control of locomotion in primates due to the evolutionary development of manipulative abilities in the primate forelimb.     

Autobiographical memory in a case of multiple personality disorder

Previous research on multiple personality disorder (MPD) has been concerned with between-personalities amnesia, and little attention has been paid to within-personality memory function. This study examined the autobiographical memory of a multiple personality patient, I.C., with cueing procedures that have proven useful in previous studies of normal and abnormal memory. Results indicated that I.C. was able to retrieve autobiographical episodes from the recent past, although her performance differed in several respects from that of matched controls. The study also revealed a striking deficit in I.C.'s autobiographical memory for childhood: She was unable to recall a single episode from prior to the age of 10 in response to various retrieval cues, whereas control subjects had no difficulty recalling numerous childhood episodes. This phenomenon of extended childhood amnesia has not been reported previously in studies of MPD.     

Occupational Representativeness and Prestige Rating: Some Observations

The authors examine occupational representativeness for its effect on prestige ratings. Compositions of occupational listings do not affect ratings. Career counseling implications are noted.     

Developmental levels of processing in metaphor interpretation

We outline a theory of metaphor interpretation. The theory posits varying levels of semantic processing and formalizes them in terms of kinds of semantic-mapping operators that transform properties of the metaphoric vehicle (i.e., predicate) into properties of the metaphoric topic (i.e., subject). We used cognitive-developmental theory to estimate the mental-processing complexity of the various mapping operators, and thereby to predict the timing of their emergence in childhood, and to construct a measure of the metaphoric-processing levels. Metaphor interpretations collected from children (aged 6-12 years) and adults were coded and scored according to the processing levels. In two separate developmental studies, processing score increased with age in a predictable way. Growth in a mental-attentional resource accounted for much of the developmental variance in metaphor interpretation. Possible moderating effects of knowledge and context are discussed.     

Cheating following success and failure in heavy and moderate social drinkers

Two groups of American undergraduates (moderate and heavy social drinkers) completed a matrix task and received either positive or negative feedback on their performance. Following this they were given a maze task, which was designed so that cheating could be detected. Heavy drinkers cheated more than moderate drinkers under success conditions (positive feedback). Heavy drinkers who received positive feedback also cheated more than heavy drinkers who received negative feedback. The results are interpreted in terms of self-handicapping theory.     

An Unwillingness to Act: Behavioral Appropriateness, Situational Constraint, and Self-Efficacy in Shyness

ABSTRACT Three reasons for the failure to demonstrate social skills were examined in an attempt to integrate social skills deficit and dysfunctional cognition approaches to self-labeled shyness To assess social skills knowledge, the willingness to demonstrate such knowledge, and self-efficacy expectations for enacting social behaviors, 40 shy and 40 nonshy adults were asked to judge the appropriateness of situated behaviors and indicate whether they characteristically enacted and felt capable of producing them Results suggested that shys may be unaware of the appropriateness of some behaviors in some situations, however, shys and nonshys more often agree on behavioral appropriateness standards Compared to nonshys, shys are less likely to enact social behaviors and tend to have low self-efficacy It was suggested that shys' self-awareness of characteristic responses and low self-efficacy expectations may contribute to failures to demonstrate social skills knowledge     

Effects of daily stress on negative mood

This article examines the influence of daily stressors on mental health in a community sample. Ss were 166 married couples who completed diaries each day for 6 weeks. In pooled within-person analyses, daily stressors explained up to 20% of the variance in mood. Interpersonal conflicts were by far the most distressing events. Furthermore, when stressors occurred on a series of days, emotional habituation occurred by the second day for almost all events except interpersonal conflicts. Contrary to certain theoretical accounts, multiple stressors on the same day did not exacerbate one another's effects: rather an emotional plateau occurred. Finally on days following a stressful event, mood was better than it would have been if the stressor had not happened. These results reveal the complex emotional effects of daily stressors, and in particular they suggest that future investigations should focus primarily on interpersonal conflicts.