Effects of time between trials on rats' and pigeons' choices with probabilistic delayed reinforcers

Parallel experiments with rats and pigeons examined reasons for previous findings that in choices with probabilistic delayed reinforcers, rats' choices were affected by the time between trials whereas pigeons' choices were not. In both experiments, the animals chose between a standard alternative and an adjusting alternative. A choice of the standard alternative led to a short delay (1 s or 3 s), and then food might or might not be delivered. If food was not delivered, there was an "interlink interval," and then the animal was forced to continue to select the standard alternative until food was delivered. A choice of the adjusting alternative always led to food after a delay that was systematically increased and decreased over trials to estimate an indifference point--a delay at which the two alternatives were chosen about equally often. Under these conditions, the indifference points for both rats and pigeons increased as the interlink interval increased from 0 s to 20 s, indicating decreased preference for the probabilistic reinforcer with longer time between trials. The indifference points from both rats and pigeons were well described by the hyperbolic-decay model. In the last phase of each experiment, the animals were not forced to continue selecting the standard alternative if food was not delivered. Under these conditions, rats' choices were affected by the time between trials whereas pigeons' choices were not, replicating results of previous studies. The differences between the behavior of rats and pigeons appears to be the result of procedural details, not a fundamental difference in how these two species make choices with probabilistic delayed reinforcers.     

Age differences in forgivingness: The role of transgression frequency and intensity

The present study examined age differences in the disposition to forgive others and the role of interpersonal transgression frequency and intensity. Data from a representative cross-sectional sample of Swiss adults (N = 451, age: 20–83 years) were used. Participants completed a self-report measure of forgivingness and indicated whether and how intense they have experienced different types of interpersonal transgressions during the past 12 months. Results indicate that older adults were, on average, more willing to forgive others than younger adults. Frequency and intensity of transgressions were negatively related with age. Moreover, the results show that transgression frequency and intensity explained, in part, age differences in forgivingness. Future directions concerning the meaning of age differences in forgivingness are discussed.     

Psychopathic personality traits in relational aggression among young adults

Psychopathy is a robust predictor of overt physical aggression that may also be relevant to relational aggression (RA). This study was conducted to investigate the utility of psychopathic personality traits in the prediction of RA in a sample of 291 college students. Hierarchical multiple regression analyses indicated that both primary and secondary psychopathic traits explained additional variance in general/peer and romantic RA beyond physical aggressiveness. Consistent with previous research, no gender differences were found on either form of RA, challenging the popular stereotype of RA as a female behavior. Moreover, psychopathic traits were not differentially predictive of RA by gender or level of physical aggressiveness. Implications of these findings for research and clinical practice are discussed.     

Gender symmetry in intimate aggression: an effect of intimacy or target sex?

Men's greater use of direct aggression is not evident in studies of intimate partner aggression. In previous research, the effects of target sex and relationship intimacy have frequently been confounded. This study sought to examine these effects separately. One hundred and seventy-four participants (59 male and 115 female) read vignette scenarios in which they were provoked by a same-sex best friend, an opposite-sex best friend, and a partner. For each target, participants estimated their likely use of direct physical and verbal aggression as well as noninjurious forms of anger expression. Results showed that men lower their aggression in the context of an intimate partnership and that this is an effect of the target's sex. In contrast, women raise their aggression in the context of an intimate partnership and this is an effect of intimacy with the target. The use of noninjurious angry behavior did not vary between targets for either sex of the participant, which suggests that the effects of target are confined to behaviors which carry an intention to harm. Possible effects of social norms and oxytocin-mediated emotional disinhibition on intimate partner aggression are discussed.     

Violent, nonviolent, and substance-related offending over the life course in a cohort of males and females treated for substance misuse as youths

Most studies on adolescent offending heterogeneity are based on general population samples, and few include individuals with substance misuse or look specifically at substance-related offending. It is also unclear how offender subtypes develop after young adulthood or how offending heterogeneity varies between genders. This study aimed to identify subgroups of offending among adolescents with misuse problems and to examine associations with offending in adulthood. The study included 1,992 females and males that consulted a clinic for adolescents with misuse problems between 1968 and 1971. Latent Class Analyses were conducted to identify subgroups based on violent and nonviolent offending before age 20. Participants were then followed until age 50 and reexamined regarding violent, nonviolent, and substance-related crimes. Associations between subgroups before age 20 and subgroups age 21-50 were examined. Before age 20, three subgroups were identified among the females and six among the males. Males were more specialized in their offending and demonstrated higher levels of offending. Results pointed to both stability and decrease of violent and nonviolent offending, and to the emergence of substance-related offending in adulthood in both genders. The connection between substance-related crimes and general delinquency in adulthood among individuals treated for substance misuse suggests that interventions should also address substance misuse for reducing the overall volume of crime. This study also highlights the importance of including females in research on offending heterogeneity.     

What cognitive abilities are involved in trail-making performance?

The cognitive abilities involved in the Connections (Salthouse, et al., 2000) version of the trail making test were investigated by administering the test, along with a battery of cognitive tests and tests of complex span and updating conceptualizations of working memory, to a sample of over 3600 adults. The results indicate that this variant of the trail making test largely reflects individual differences in speed and fluid cognitive abilities, with the relative contributions of the two abilities varying according to particular measure of performance considered (e.g., difference, ratio, or residual). Relations of age on trail making performance were also examined. Although strong age differences were evident in the Connections and working memory measures, with both sets of variables there was nearly complete overlap of the age differences with individual differences in speed and fluid cognitive abilities.     

Sex differences in latent cognitive abilities ages 5 to 17: Evidence from the Differential Ability Scales—Second Edition

Sex differences in the latent general and broad cognitive abilities underlying the Differential Ability Scales, Second Edition were investigated for children and youth ages 5 through 17. Multi-group mean and covariance structural equation modeling was used to investigate sex differences in latent cognitive abilities as well as changes in these differences across age. Most broad abilities showed mean differences across the sexes, and all such differences varied across ages. Girls showed an advantage on the processing speed (Gs) first-order residual factor. Girls also showed advantages at some ages on free-recall memory, a narrow ability of long term retrieval (Glr). Boys showed a developmentally-related advantage on a visual-spatial ability (Gv) first-order residual factor, depending on age. Younger girls showed an advantage on short-term memory (Gsm). No statistically significant sex differences were shown on the latent comprehension-knowledge (Gc) factor, or on a second-order, latent g factor. Boys showed larger variances for several broad abilities, some substantial, but those differences were not statistically significant.     

Humor ability reveals intelligence, predicts mating success, and is higher in males

A good sense of humor is sexually attractive, perhaps because it reveals intelligence, creativity, and other ‘good genes’ or ‘good parent’ traits. If so, intelligence should predict humor production ability, which in turn should predict mating success. In this study, 400 university students (200 men and 200 women) completed measures of abstract reasoning (Raven's Advanced Progressive Matrices), verbal intelligence (the vocabulary subtest of the Multidimensional Aptitude Battery), humor production ability (rated funniness of captions written for three cartoons), and mating success (from the Sexual Behaviors and Beliefs Questionnaire). Structural equation models showed that general and verbal intelligence both predict humor production ability, which in turn predicts mating success, such as lifetime number of sexual partners. Also, males showed higher average humor production ability. These results suggest that the human sense of humor evolved at least partly through sexual selection as an intelligence-indicator.     

Need for Cognition and false recall

Two experiments investigated whether Need for Cognition (NFC) affected false recall in the Deese-Roediger-McDermott (DRM) paradigm. In the first experiment, participants were presented with DRM lists and given one attempt to recall the items. In the second experiment, participants were presented with DRM lists under full or divided attention and were given three consecutive recall tests. In Experiment 2, high-NFC individuals exhibited increased false recall across successive recall attempts in both the full and divided attention conditions whereas low-NFC individuals did not. Furthermore, high-NFC individuals in the full attention condition exhibited increased levels of true recall across successive tests. These results show that the individual differences in the ways in which individuals process information can affect true and false recall in the DRM task.     

Commonly-defined and individually-defined posttraumatic growth in the US and Japan

Posttraumatic growth (PTG) is the experience of positive change resulting from the struggle with major life crises. Research on PTG has relied on instruments such as the Posttraumatic Growth Inventory (PTGI: Tedeschi &; Calhoun, 1996), in which items that describe positive changes are assumed to represent personal growth equally for all people. However, some positive changes may indicate greater growth for some people. Individually-defined PTG may differ from commonly-defined PTG. The purpose of this study was to explore the relationships between these two definitions of PTG and how culture affects them. Participants from the US (n = 456) and Japan (n = 279) indicated the degree to which each change in the PTGI represented personal growth. Results from mixed-model analyses of variance revealed that there were main effects for defined growth as well as interaction effects for all PTGI factors. For example, US participants reported greater growth on the factors Relating to Others and New Possibilities for the commonly-defined level, but once individually-defined PTG was considered, growth scores for US participants decreased substantially, and more so than for Japanese participants. Discussion addresses cultural and individual differences in the subjective definitions of PTG and highlights several directions for future research.