In search of the psychopathic sexuality taxon: indicator size does matter

Recent research has suggested that a qualitatively distinct subtype of psychopathic sex offender can be identified via taxometric analyses (Harris et al., 2007). In this study we attempted to replicate the hypothesized psychopathic sexuality taxon in a group of 503 male sexual offenders using data from the Psychopathy Checklist-Revised (PCL-R:Hare, 2003) and five coercive and precocious sexuality items. Ambiguous to dimensional results were obtained when, in a replication of the Harris et al. (2007) study,dichotomized indicators were analyzed with summed input maximum covariance (MAXCOV). Clearly dimensional results, however, were obtained when higher correlating and more valid quasi-continuous indicators were analyzed with traditional (input variables not summed) MAXCOV, and both dichotomous and quasi-continuous indicators were analyzed with mean above minus below a cut (MAMBAC) and latent-mode factor analysis (L-Mode). These results suggest that Harris et al. (2007) may have mistaken the random fluctuations of weakly correlating and poorly differentiating indicators for a taxon. Consistent with the vast majority of earlier research,our results suggest that psychopathy (with or without coercive and precocious sexuality) is a dimensional construct.     

Rhesus monkeys lack a consistent peak-end effect

In humans, the order of receiving sequential rewards can significantly influence the overall subjective utility of an outcome. For example, people subjectively rate receiving a large reward by itself significantly higher than receiving the same large reward followed by a smaller one (Do, Rupert, & Wolford, 2008). This result is called the peak-end effect. A comparative analysis of order effects can help determine the generality of such effects across primates, and we therefore examined the influence of reward-quality order on decision making in three rhesus macaque monkeys (Macaca mulatta). When given the choice between a high-low reward sequence and a low-high sequence, all three monkeys preferred receiving the high-value reward first. Follow-up experiments showed that for two of the three monkeys their choices depended specifically on reward-quality order and could not be accounted for by delay discounting. These results provide evidence for the influence of outcome order on decision making in rhesus monkeys. Unlike humans, who usually discount choices when a low-value reward comes last, rhesus monkeys show no such peak-end effect.     

The relation between ethnic group attachment and prosocial tendencies: The mediating role of cultural values

Studies suggest that Mexican–American youths who feel attached to their ethnic group engage in more prosocial behaviors. However, the psychological mechanisms that account for this association are not clear. Drawing on social identity and self‐categorization theories, we examined whether the association between ethnic group attachment and tendencies to engage in six distinct types of prosocial behaviors was mediated by familism and Mainstream American values among Mexican American youths. Ethnic group attachment, familism, Mainstream American values, and prosocial tendencies were assessed among 207 Mexican–American early adolescents using an interview format. Latent variable path models showed that ethnic group attachment was associated with greater tendencies to engage in compliant, emotional, dire, and anonymous helping, and that each of these associations was at least partially mediated by greater familism values. Mainstream American values were related to greater tendencies to engage in public prosocial behavior and less altruistic behavior, but did not mediate the associations between ethnic group attachment and prosocial tendencies. The theoretical and practical implications of these findings are addressed. Copyright © 2010 John Wiley & Sons, Ltd.     

THE EFFICACY OF WOMEN'S RESISTANCE STRATEGIES IN RAPE SITUATIONS

The effectiveness of women's resistance strategies for reducing the severity of sexual abuse and physical injury during sexual assaults was analyzed in a variety of assault circumstances. Data were obtained from police reports and court testimonies of 274 women (96% White, 4% Black) who either were raped or avoided rape by subsequently incarcerated violent stranger rapists. Statistical analyses showed that particular resistance strategies were effective in specific situations. Women who fought back forcefully were more likely to avoid rape than women who did not fight back, regardles of whether a waepon was present. Forceful fighting resistance was related to increased physical injury when a weapon was present, but most physical injury was caused by nonlethal weapons. Women who screamed or fled when confronted with weapons experienced less severe sexual abuse. Increased physical injury was associated with pleading, crying, or reasoning indoors. Women who used drugs or alcohol experienced more severe sexual abuse and physical injury.     

‘Please sort these voice recordings into 2 identities’: Effects of task instructions on performance in voice sorting studies

We investigated the effects of two types of task instructions on performance on a voice sorting task by listeners who were either familiar or unfamiliar with the voices. Listeners were asked to sort 15 naturally varying stimuli from two voice identities into perceived identities. Half of the listeners sorted the recordings freely into as many identities as they perceived; the other half were forced to sort stimuli into two identities only. As reported in previous studies, unfamiliar listeners formed more clusters than familiar listeners. Listeners therefore perceived different naturally varying stimuli from the same identity as coming from different identities, while being highly accurate at telling apart the stimuli from different voices. We further show that a change in task instructions – forcing listeners to sort stimuli into two identities only – helped unfamiliar listeners to overcome this selective failure at ‘telling people together’. This improvement, however, came at the cost of an increase in errors in telling people apart. For familiar listeners, similar non-significant trends were apparent. Therefore, even when informed about correct number of identities, listeners may fail to accurately perceive identity further highlighting that voice identity perception in the context of natural within-person variability is a challenging task. We discuss our results in terms of similarities and differences to findings in the face perception literature and their importance in applied settings, such as forensic voice identification.