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.     

Reinterpreting the Myers-Briggs Type Indicator From the Perspective of the Five-Factor Model of Personality

The Myers-Briggs Type Indicator (MBTI; Myers & McCaulley, 1985) was evaluated from the perspectives of Jung's theory of psychological types and the five-factor model of personality as measured by self-reports and peer ratings on the NEO Personality Inventory (NEO-PI; Costa & McCrae, 1985b). Data were provided by 267 men and 201 women ages 19 to 93. Consistent with earlier research and evaluations, there was no support for the view that the MBTI measures truly dichotomous preferences or qualitatively distinct types; instead, the instrument measures four relatively independent dimensions. The interpretation of the Judging-Perceiving index was also called into question. The data suggest that Jung's theory is either incorrect or inadequately operationalized by the MBTI and cannot provide a sound basis for interpreting it. However, correlational analyses showed that the four MBTI indices did measure aspects of four of the five major dimensions of normal personality. The five-factor model provides an alternative basis for interpreting MBTI findings within a broader, more commonly shared conceptual framework.     

Is dependence on phonological information in children's reading a product of instructional approach?

Eight-year-old British children were found to be less accurate at rejecting pseudohomophones than ordinary nonwords in a lexical decision task, but 8-year-old New Zealand children did not show this effect. A subsequent homophone decision task showed that this difference was not due to the New Zealand children being unable to distinguish pseudohomophones from other nonwords. The New Zealand children, however, were less accurate than the British children in pronouncing the pseudohomophones they had identified. It was argued that the British children tended to sound out the items before making a choice in the lexical decision task, which gave salience to phonological rather than visual information, resulting in increased errors to the pseudohomophones. It was concluded that where the British children showed this dependency on use of phonological information it was a product of the teaching approach they had experienced.     

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.     

Agreeable fancy or disagreeable truth? Reconciling self-enhancement and self-verification

Three studies asked why people sometimes seek positive feedback (self-enhance) and sometimes seek subjectively accurate feedback (self-verify). Consistent with self-enhancement theory, people with low self-esteem as well as those with high self-esteem indicated that they preferred feedback pertaining to their positive rather than negative self-views. Consistent with self-verification theory, the very people who sought favorable feedback pertaining to their positive self-conceptions sought unfavorable feedback pertaining to their negative self-views, regardless of their level of global self-esteem. Apparently, although all people prefer to seek feedback regarding their positive self-views, when they seek feedback regarding their negative self-views, they seek unfavorable feedback. Whether people self-enhance or self-verify thus seems to be determined by the positivity of the relevant self-conceptions rather than their level of self-esteem or the type of person they are.     

Ask and You Shall be Given: Request Size and Donations to a Good Cause1

In an attempt to replicate the findings reported in this Journal by Weyant and Smith (1987), members or recent donors to a Canadian civil liberties organization were asked to donate money under one of three conditions: (a) In the control condition, they were simply asked for a donation; (b) in the “smaller request” condition, they were asked to make a donation, but amounts of Canadian $30 to $100 were suggested; and (c) in the “larger request” condition, amounts of $50 to $250 were suggested. Unlike the Weyant and Smith studies, we found no difference in the proportion of respondents making a donation, but significant differences in the size of the donations made by those making donations. In our study, the most effective way of getting large donations was to ask for a large amount. It was suggested that the most likely explanations for the differences in the results of the two studies were the following: First, our target population were previous donors to the organization, whereas those in the Weyant and Smith studies were not likely to have been. Previous research suggests that those who had been donors previously are influenced, positively, by requests for a specific large donation, whereas those not previously approached are, if anything, negatively influenced. Second, our “larger request” appears to be within a plausible range for donations, whereas the larger request in the Weyant and Smith study may have been seen as being outside of the plausible range. In any case, however, we would recommend caution in drawing a conclusion about the most effective request size to encourage people to donate money to charity.     

Quantum mechanics as subjectivity and projective stimulus

In this paper I attempt to show that subjectivity, as an input to the creative core of physics, is a misunderstood, but crucial factor. Utilizing Rapaport's fundamental paper, Principles Underlying Projective Techniques which identifies the determinants of the projective technique as: 1. lack of organization, 2. undifferentiation, 3. closeness to the core of the personality, and 4. the meaning of the stimulus being unknown to the subject, a link is suggested to quantum mechanics. It is further suggested the revolutionary nature of quantum mechanics satisfies the projective criterion of the material being unorganized or unfamiliar so that the function of organization can become predominant (Rapaport 1942, p. 93).     

EFFECTS OF WAIT-TIME AND INTERTRIAL INTERVAL DURATIONS ON LEARNING BY CHILDREN WITH MULTIPLE HANDICAPS

We investigated the influence of teacher wait-time and intertrial interval durations on the performance of 4 multiply handicapped students during instruction in 10 skills. Four experimental conditions were evaluated: long wait-time and long intertrial interval, long wait-time and short intertrial interval, short wait-time and long intertrial interval, and short wait-time and short intertrial interval. Instructors attempted to keep short intervals as close as possible to 1 s and long intervals as close as possible to 10 s for both variables. Results showed that student performance was superior under the long wait-time conditions irrespective of the length of the intertrial interval.