Weak ventral striatal responses to monetary outcomes predict an unwillingness to resist cigarette smoking

As a group, cigarette smokers exhibit blunted subjective, behavioral, and neurobiological responses to nondrug incentives and rewards, relative to nonsmokers. Findings from recent studies suggest, however, that there are large individual differences in the devaluation of nondrug rewards among smokers. Moreover, this variability appears to have significant clinical implications, since reduced sensitivity to nondrug rewards is associated with poorer smoking cessation outcomes. Currently, little is known about the neurobiological mechanisms that underlie these individual differences in the responsiveness to nondrug rewards. Here, we tested the hypothesis that individual variability in reward devaluation among smokers is linked to the functioning of the striatum. Specifically, functional magnetic resonance imaging was used to examine variability in the neural response to monetary outcomes in nicotine-deprived smokers anticipating an opportunity to smoke—circumstances found to heighten the devaluation of nondrug rewards by smokers in prior work. We also investigated whether individual differences in reward-related brain activity in those expecting to have access to cigarettes were associated with the degree to which the same individuals subsequently were willing to resist smoking in order to earn additional money. Our key finding was that deprived smokers who exhibited the weakest response to rewards (i.e., monetary gains) in the ventral striatum were least willing to refrain from smoking for monetary reinforcement. These results provide evidence that outcome-related signals in the ventral striatum serve as a marker for clinically meaningful individual differences in reward-motivated behavior among nicotine-deprived smokers.     

Threatening scenes but not threatening faces shorten time-to-contact estimates

We previously reported that time-to-contact (TTC) judgments of threatening scene pictures (e.g., frontal attacks) resulted in shortened estimations and were mediated by cognitive processes, and that judgments of threatening (e.g., angry) face pictures resulted in a smaller effect and did not seem cognitively mediated. In the present study, the effects of threatening scenes and faces were compared in two different tasks. An effect of threatening scene pictures occurred in a prediction-motion task, which putatively requires cognitive motion extrapolation, but not in a relative TTC judgment task, which was designed to be less reliant on cognitive processes. An effect of threatening face pictures did not occur in either task. We propose that an object’s explicit potential of threat per se, and not only emotional valence, underlies the effect of threatening scenes on TTC judgments and that such an effect occurs only when the task allows sufficient cognitive processing. Results are consistent with distinctions between predator and social fear systems and different underlying physiological mechanisms. Not all threatening information elicits the same responses, and whether an effect occurs at all may depend on the task and the degree to which the task involves cognitive processes.     

Interculturality and Early Attachment: A Comparison of Urban/ <Emphasis Type="Italic">Non-Mapuche</Emphasis> and Rural/<Emphasis Type="Italic">Mapuche</Emphasis> Mother-Baby Dyads in Chile

It is well known in the field that culture and context play an important role in child rearing and parenting practices. However, many studies do not address the cultural dimension of attachment, although evidence indicates that aspects of early attachment differ across cultures. With the goal of comparing the quality of mother–baby interactions, this study analyzed attachment behaviors and maternal sensitivity in two settings: urban/non-Mapuche and rural/Mapuche in Chile. The sample was composed of 34 mother-baby dyads (17 urban/non-Mapuche and 17 rural/Mapuche) with 12-month-old children. During a feeding episode, the attachment style of the interaction was assessed with the Attachment during Stress scale, and maternal sensitivity was evaluated with the Child-Adult Relationship Experimental Index-Toddlers (CARE-Index). The groups differed in their interaction attachment style and in affective and proximity modalities: Urban/non-Mapuche mothers tended to have secure and ambivalent attachment styles, and rural/Mapuche mothers tended to have avoidant styles. When educational level is controlled, ethnicity group can explain the differences in mothers’ attachment styles. The findings of the study and their implications are discussed.     

Young children's understanding of displaced aggression

According to previous research, young children do not understand displaced aggression. The present study examines the early phases of the understanding of the causes of moderately and extremely displaced aggression. Preschool and kindergarten children (3 to 5 years of age) viewed eight videotaped episodes of displaced aggression. Their comprehension of this aggression was assessed by means of open ended questions and forced choice picture selections. By age 5 most children had some understanding of displaced aggression, but this understanding was not complete. The early understanding revealed in the present study may be due to the use of short, simple realistic videotaped episodes appropriate for the limited processing abilities of young children. Extreme displacement was not more difficult to understand than moderate displacement.