Genetic Influence on the Variance in Coincidence Timing and its Covariance with IQ: A Twin Study

Performance measures on a coincidence timing task have previously been associated with psychometric IQ suggesting that the ability of an individual to devote processing resources at the required time may account for some of intelligence test variance. Using the twin design, this study investigates whether genetic variability explains some of the variance in coincidence timing and whether common genetic factors account for the association with intellectual functioning. Fifty-five 16-year old twin pairs (28 MZ, 27 DZ) were tested. Individual differences in number of hits (HITS), mean absolute error (MAE), and intra-individual trial-to-trial consistency (SD) were significantly influenced by genetic factors, accounting for approximately 50 percent of the variance. The correlation between coincidence timing and psychometric IQ was confirmed and ranged from 0.11 to 0.53 with a mean correlation of 0.33. In the limited sample, the correlation between IQ and the coincidence timing measures appeared to be mediated largely by a unique environmental factor, with only a small loading of SD on the genetic factor influencing IQ. However, as the confidence intervals in the other genetic cross loadings are large, we cannot exclude the possibility of a much stronger genetic influence.     

维特根斯坦和传统

维特根斯坦在奥地利-维也纳传统中长大,并坚定地植根于这一传统之中。任何理解他的人格的尝试都必须设法把他置于这一背景中加以考察。但维特根斯坦作为哲学家的工作,几乎完全是在他并不分享其文化传统、并且对他本人是非常不相宜的环境中完成的。     

Maternal behavior, paternal behavior, and pup survival in CD-1 albino mice (Mus musculus) in three different housing conditions

Parental behavior, food consumption, and pup development in litters of CD-1 albino mice (Mus musculus) with single mothers or paired mothers in 3 different housing conditions were compared. Fewer pups survived when parents were required to run in a wheel to obtain food, and these pups had lower weights than pups in the wheel-noncontingent and no-wheel groups. The presence of the male facilitated pup survival in the wheel-contingent group but had no effect on pup growth. Mice in the wheel-contingent group ran more revolutions than those in the wheel-noncontingent group and spent less time in parental care. In the wheel-contingent group, males spent more time running and ate less food than females, suggesting that males may indirectly facilitate pup development by providing food for the mother. The results suggest that the presence of the male increases pup care and may facilitate maternal behavior under appropriate environmental conditions.     

Peer pressure and drug use--exploding the myth

"Peer pressure" and "everyone is doing it" have been used as excuses for some drug-taking behavior for too long. We must look harder into reasons for drug use and neither accept these concepts nor teach our young people that this is what is really happening.     

High school polydrug users and abusers

Among 433 high school seniors, 12% were determined to be either polydrug users or abusers. In comparison to the non-polydrug users, polydrug users and abusers were significantly more likely to indicate: (1) physical abuse by and many conflicts with parents; (2) self-ratings of lazy, bored, rejected, and unhealthy, (3) serious suicidal thoughts, delinquent behavior, early use of marijuana and alcohol, and the tendency to drink more than six alcoholic drinks at a sitting; and (4) agreement with the following statements: "If something feels good, I usually do it and don't worry about the consequences" and "I try to play as much as possible and work as little as possible." These findings suggest that many polydrug users and abusers are either seeking pleasure or trying to escape pain. Because of the different reasons behind polydrug use, a variety of treatment and prevention strategies will be necessary to curb the polydrug problem among adolescents.     

Psychophysiologic correlates of Type A behavior: Comments on Houston (1983) and Holmes (1983)

On the basis of a literature review, B. K. Houston (1983, Journal of Research in Personality, 17, 22–39) concluded that there is a reliable but relatively weak association between Type A (coronary-prone) behavior and heightened physiologic reactivity. D. S. Holmes (1983, Journal of Research in Personality, 17, 40–47) contends that by failing to take into account dependent measures yielding null results, Houston overestimated the consistency with which A/B differences have been obtained. In the present article, we show that it is critical to take into account the method used to assess Type A behavior. Structured Interview assessments show a more consistent association with reactivity than those based on the Jenkins Activity Survey. We then point out that, for certain physiologic measures, null effects do not necessarily reflect an absence of A/B differences in sympathetic-adrenomedullary activity. Other issues that are discussed include the role of situational parameters in eliciting hyperresponsiveness in Type A's, the problem of evaluating the magnitude and importance of A/B effects, and the need for a more theoretical approach to the study of Type A behavior.