Inclusive fitness theory provides a compelling explanation for the evolution of altruism among kin. However, a completely satisfactory account of non-kin altruism is still lacking. The present study compared the level of altruism found among siblings with that found among friends and mates and sought to reconcile the findings with an evolutionary explanation for human altruism. Participants (163 males and 156 females) completed a questionnaire about help given to a sibling, friend, or mate. Overall, participants gave friends and mates as (...) much or more help than they gave siblings. However, as the cost of help increased, siblings received a progressively larger share of the help, whereas friends and mates received a progressively smaller share, despite the fact that participants were closer emotionally to friends and mates than they were to siblings. These findings help to explain the relative standing of friends and mates as recipients of altruistic aid. (shrink)

Background -/- Psychopathy is a mental health disorder characterized by callous and impulsive antisocial behavior, and it is associated with a high incidence of violent crime, substance abuse, and recidivism. Recent studies suggest that the striatum may be a key component of the neurobiological basis for the disorder, although structural findings have been mixed, and functional connectivity of the striatum in psychopathy has yet to be fully examined. Methods -/- We performed a multimodal neuroimaging study of striatum volume and functional (...) connectivity in psychopathy using a large sample of adult male prison inmates (N = 124). We conducted volumetric analyses in striatal subnuclei and subsequently assessed resting-state functional connectivity in areas where volume was related to psychopathy severity. -/- Results -/- Total Psychopathy Checklist Revised and factor 2 scores (which index the impulsive/antisocial traits of psychopathy) were associated with larger striatal subnuclei volumes and increased volume in focal areas throughout the striatum, particularly in the nucleus accumbens and putamen bilaterally. Furthermore, at many of the striatal areas where volume was positively associated with factor 2 scores, psychopathy severity was also associated with abnormal functional connectivity with other brain regions, including dorsolateral prefrontal cortex, ventral midbrain, and other areas of the striatum. The results were not attributable to age, race, IQ, substance use history, or intracranial volume. Conclusions -/- These findings associate the impulsive/antisocial dimension of psychopathy with enlarged striatal subnuclei and aberrant functional connectivity between the striatum and other brain regions. Furthermore, the colocalization of volumetric and functional connectivity findings suggests that these neural abnormalities may be pathophysiologically linked. (shrink)

Recent brain imaging studies using functional magnetic resonance imaging (fMRI) have implicated insula and anterior cingulate cortices in the empathic response to another’s pain. However, virtually nothing is known about the impact of the voluntary generation of compassion on this network. To investigate these questions we assessed brain activity using fMRI while novice and expert meditation practitioners generated a loving-kindness-compassion meditation state. To probe affective reactivity, we presented emotional and neutral sounds during the meditation and comparison periods. Our main hypothesis (...) was that the concern for others cultivated during this form of meditation enhances affective processing, in particular in response to sounds of distress, and that this response to emotional sounds is modulated by the degree of meditation training. The presentation of the emotional sounds was associated with increased pupil diameter and activation of limbic regions (insula and cingulate cortices) during meditation (versus rest). During meditation, activation in insula was greater during presentation of negative sounds than positive or neutral sounds in expert than it was in novice meditators. The strength of activation in insula was also associated with self-reported intensity of the meditation for both groups. These results support the role of the limbic circuitry in emotion sharing. The comparison between meditation vs. rest states between experts and novices also showed increased activation in amygdala, right temporo-parietal junction (TPJ), and right posterior superior temporal sulcus (pSTS) in response to all sounds, suggesting, greater detection of the emotional sounds, and enhanced mentation in response to emotional human vocalizations for experts than novices during meditation. Together these data indicate that the mental expertise to cultivate positive emotion alters the activation of circuitries previously linked to empathy and theory of mind in response to emotional stimuli.. (shrink)

Our review addresses what psychopathy is, whether variants or subtypes exist (i.e., primary and secondary, unsuccessful and successful), the sorts of causal influences that contribute to psychopathy, how early in development psychopathy can validly be identified, and how psychopathy relates to future criminal behavior and treatment outcomes. Despite.

PLoS ONE 3(3): e1897. doi:10.1371/journal.pone.