Rebellious teens? Genetic and environmental influences on the social attitudes of adolescents

Genetic and environmental influences in social attitudes were investigated in adopted and nonadopted children (N = 654) and their biological and adoptive relatives in the Colorado Adoption Project. Conservatism and religious attitudes were measured in the children annually from ages 12 to 15 and in the parents during the 12-year-old visit. Multivariate genetic model fitting indicated that both conservatism and religious attitudes are strongly influenced by shared-family environmental factors throughout adolescence. In contrast to previous findings from twin studies, which suggest that genetic influence on social attitudes does not emerge until adulthood, the present study detected significant genetic influence in conservatism as early as age 12. There was no evidence of genetic influence, however, on religious attitudes during adolescence.     

The self-importance of moral identity

Recent theorizing in moral psychology extends rationalist models by calling attention to social and cultural influences (J. Haidt, 2001). Six studies using adolescents, university students, and adults measured the associations among the self-importance of moral identity, moral cognitions, and behavior. The psychometric properties of the measure were assessed through an examination of the underlying factor structure (Study 1) and convergent, nomological, and discriminant validity analyses (Studies 2 and 3). The predictive validity of the instrument was assessed by examinations of the relationships among the self-importance of moral identity, various psychological outcomes, and behavior (Studies 4, 5, and 6). The results are discussed in terms of models of moral behavior, social identity measurement, and the need to consider moral self-conceptions in explaining moral conduct.     

The effects of encoding task on age-related differences in the functional neuroanatomy of face memory

Age-related differences in brain activity mediating face recognition were examined using positron emission tomography. Participants encoded faces using a pleasant-unpleasant judgment, a right-left orientation task, and intentional learning. Scans also were obtained during recognition. Both young and old groups showed signficant effects of encoding task on recognition accuracy, but older adults showed reduced accuracy overall. Increased brain activity in older adults was similar to that seen in young adults during conditions associated with deeper processing, but was reduced during the shallow encoding and recognition conditions. Left prefrontal activity was less in older adults during encoding, but greater during recognition. Differential correlations of brain activity and behavior were found that suggest older adults use unique neural systems to facilitate face memory.     

Effect of a total smoking ban in a maximum security psychiatric hospital

An archival study was performed in a maximum security forensic hospital to evaluate the effects of a total ban on smoking and all tobacco products. One hundred and forty patients were characterized as nonsmokers or light, moderate or heavy smokers. Patient records for the four weeks prior to the ban were compared with their records for the four weeks subsequent to the ban. Numbers of sick calls, total disruptive behaviors and verbal aggression declined markedly and significantly following the ban in those patients previously classified as moderate or heavy smokers. Weight increased significantly, but almost equally regardless of previous smoking status. Patients, and eventually staff, tolerated the smoking ban without significant negative effects. Patients relied very little on treatment modalities to alleviate nicotine withdrawal. Pre-ban apprehension by staff and patients dissipated with time after the smoking ban started.     

The influence of distinctive processing on retrieval-induced forgetting

Recall of a portion of a previously experienced list benefits subsequent recall of that portion of the list but leads to poorer recall of nonpracticed items from the same set (Anderson, Bjork, & Bjork, 1994). One explanation for this retrieval-induced forgetting is that during practice of part of a set, the non-practiced items compete for recall and are suppressed; this suppression process inhibits later recall of the nonpracticed items. Two experiments were conducted to investigate the relationship between distinctive processing of the original set and retrieval-induced forgetting, on the assumption that distinctive processing reduces response competition. In the first experiment, distinctive processing induced by difference judgments among the studied items did reduce forgetting relative to a standard encoding task and a similarity judgment task. In fact, the difference judgment task completely eliminated retrieval-induced forgetting. In the second experiment, the similarity judgment task was analyzed in relation to a task assumed to foster associative integration (Anderson & McCulloch, 1999). Even though the similarity judgment met the requirements for associative integration, retrieval-induced forgetting persisted following similarity judgment. The results are consistent with the view that distinctive processing benefits memory within an organizational context (Hunt & McDaniel, 1993; Smith & Hunt, in press).     

Longitudinal changes in the contribution of genetic and environmental influences to symptoms of depression in older male twins

Genetically informative longitudinal data on self-reported symptoms of depression allow for an investigation of the causes of stability and change in depression symptoms throughout adult life. In this report, the authors investigated the relative contribution of genetic and environmental influences to symptoms of depression in 83 monozygotic and 84 dizygotic male twin pairs from the National Heart, Lung, and Blood Institute (NHLBI) Twin Study. Participants first completed the Center for Epidemiologic Studies-Depression (CES-D) scale in 1985-1986 and again during 1995-1997. Mean age of twins at baseline was 63 years, range 59 to 70. From cross-sectional genetic analyses we estimated the heritability of CES-D to be 25% (95% confidence interval [CI], 11%-39%) at baseline and 55% (95% CI, 40%-71%) at follow-up. Fitting longitudinal genetic models to the two-wave data, we found that stability of symptoms over the 10-year follow-up was due primarily to continuity of genetic influences.     

Infants' formation and use of categories to segregate objects

Four- and-a-half-month-old infants' (N = 100) category formation and use was studied in a series of five experiments. For each experiment, the test events featured a display composed of a cylinder and a box. Previous research showed that this display is not clearly parsed as a single unit or as two separate units by infants of this age. Immediately prior to testing, infants were shown a set of category exemplars. Knowledge about this category could help infants disambiguate the test display, which contained a novel exemplar of this category. Clear interpretation of the test display as composed of two separate units (as indicated by infants' longer looking at the move-together than at the move-apart test event) was taken as evidence of category formation and use. In Experiments 1 and 5, infants' prior experience with a set of three different boxes that were similar to the test box facilitated their segregation of the test display. Experiment 2 showed that three different exemplars are necessary: prior experience with any two of the three boxes used in Experiment 1 did not facilitate infants' segregation of the test display. Experiment 3 showed that variability in the exemplar set is necessary: prior experience with three identical boxes did not facilitate infants' segregation of the test display. Experiment 4 showed that under these conditions of very brief prior exposure, similarity between the exemplar set and test box is necessary: prior experience with three different boxes that were not very similar to the test box did not facilitate infants' segregation of the test display. Together, these findings suggest that: (a) number of exemplars, variability, and similarity in the exemplar set are important for infants' category formation, and (b) infants use their category knowledge to determine the boundaries of the objects in a display.