Evolutionary function of dreams: A test of the threat simulation theory in recurrent dreams

proposed an intriguing and detailed evolutionary theory of dreams which stipulates that the biological function of dreaming is to simulate threatening events and to rehearse threat avoidance behaviors. The goal of the present study was to test this theory using a sample of 212 recurrent dreams that was scored using a slightly expanded version of the DreamThreat rating scale. Six of the eight hypotheses tested were supported. Among the positive findings, 66% of the recurrent dream reports contained one or more threats, the threats tended to be dangerous and aimed at the dreamer, and when facing a threat, the dreamer tended to take defensive or evasive actions that were possible and reasonable. However, less than 15% of the recurrent dreams depicted realistic and probable situations critical for one's physical survival or reproductive success and the dreamer rarely succeeded in fleeing the threat despite important and appropriate efforts. The findings thus provide mixed support for the threat simulation theory.     

Transient and enduring spatial representations under disorientation and self-rotation

Current theories of environmental cognition typically differentiate between an online, transient, and dynamic system of spatial representation and an offline and enduring system of memory representation. Here the authors present additional evidence for such 2-system theories in the context of the disorientation paradigm introduced by R. F. Wang and E. S. Spelke (2000). Several experiments replicate the finding that disorientation results in a decrease in the precision of people's estimates of relative directions. In contrast to the typical interpretation of this effect as indicating the primacy of a transient spatial system, the present results are generally more consistent with an interpretation of it as indicating a switch from a relatively precise online representation to a relatively coarse enduring one. Further experiments examine the relative precision of transient and enduring representations and show that switching between them does not require disorientation, but can also be produced by self-rotations as small as 135 degrees .     

Postpartum feeding attitudes, maternal depression, and breastfeeding in Barbados

Maternal feeding attitudes, maternal moods and infant feeding practices during the first 6 months postpartum were assessed in 226 healthy, well-nourished Barbadian mother-infant dyads. Factor analysis of the feeding attitudes questionnaire resulted in six independent factors. The belief that breastfeeding was better than bottle-feeding was associated with higher family income, more information seeking behavior and older maternal age at the time of her first pregnancy. Women who believed that breastfeeding was better at 7 weeks postpartum were also more likely to breastfeed at concurrent and later ages, up to 6 months postpartum. This belief was also associated with less maternal depression at 7 weeks and 6 months. The association between feeding attitudes and actual feeding practices was significant even after correcting for maternal moods and other background variables. Conversely, after controlling for feeding attitudes, maternal mood at 7 weeks was still significantly associated with infant feeding practices at 6 months. Thus, feeding attitudes and maternal moods were closely linked, but each contributed independently and uniquely to different aspects of breastfeeding, especially at 6 months. These findings suggest that early intervention addressing maternal feeding attitudes, may improve the extent of breastfeeding and the health of children in this setting.     

Bed-sharing, breastfeeding and maternal moods in Barbados

Bed-sharing among Barbadian mothers and infants was studied in relationship to maternal and infant characteristics. This prospective study followed 226 healthy, well-nourished mother–infant dyads at birth, 7 weeks, 3 months, and 6 months postpartum. At each age, approximately half of the infants shared the same beds as their mothers. Bed-sharing was associated with demographic characteristics, especially fewer home conveniences, and also maternal characteristics, including less information seeking by the mother and younger maternal age at first pregnancy. Bed-sharing was also associated with lower infant birth weights. Maternal moods were significantly correlated with bed-sharing, such that mothers who reported having more despair and anxiety were also more likely to sleep with their infants. Bed-sharing was also significantly associated with increased breastfeeding at all infant ages, but this relationship was no longer significant once the effects of maternal moods were controlled. This study emphasizes the importance of assessing maternal moods in studies evaluating the risk and benefits of bed-sharing.     

Impulsive-compulsive sexual behavior

Impulsive-compulsive sexual behavior is a little studied clinical phenomenon which affects approximately 5% to 6% of the population. In the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition-Text Revision, it is classified as an impulse control disorder not otherwise specified or a sexual disorder not otherwise specified. It may be placed in a possible new category in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition called substance and behavioral addictions. This clinical entity is reviewed and the merit of classifying it as an addiction is assessed. Information is presented regarding its diagnostic criteria, epidemiology, types of behavior it can involve, relationship to hypersexuality, comorbidities, treatment, and etiology. The data regarding this disorder and its overlap with chemical addiction is limited. If the two disorders are to be grouped together, further data are needed.     

Using FMRI to study the neural correlates of virtual reality analgesia

Excessive pain during medical procedures, such as burn wound dressing changes, is a widespread medical problem and is especially challenging for children. This article describes the rationale behind virtual reality (VR) pain distraction, a new non-pharmacologic adjunctive analgesia, and gives a brief summary of empirical studies exploring whether VR reduces clinical procedural pain. Results indicate that patients using VR during painful medical procedures report large reductions in subjective pain. A neuroimaging study measuring the neural correlates of VR analgesia is described in detail. This functional magnetic resonance imaging pain study in healthy volunteers shows that the large drops in subjective pain ratings during VR are accompanied by large drops in pain-related brain activity. Together the clinical and laboratory studies provide converging evidence that VR distraction is a promising new non-pharmacologic pain control technique.     

Anatomy of a decision: striato-orbitofrontal interactions in reinforcement learning, decision making, and reversal

The authors explore the division of labor between the basal ganglia-dopamine (BG-DA) system and the orbitofrontal cortex (OFC) in decision making. They show that a primitive neural network model of the BG-DA system slowly learns to make decisions on the basis of the relative probability of rewards but is not as sensitive to (a) recency or (b) the value of specific rewards. An augmented model that explores BG-OFC interactions is more successful at estimating the true expected value of decisions and is faster at switching behavior when reinforcement contingencies change. In the augmented model, OFC areas exert top-down control on the BG and premotor areas by representing reinforcement magnitudes in working memory. The model successfully captures patterns of behavior resulting from OFC damage in decision making, reversal learning, and devaluation paradigms and makes additional predictions for the underlying source of these deficits.     

Self-benefiting in the allocation of scarce resources: leader-follower effects and the moderating effect of social value orientations

Previous research on the allocation of scarce resources suggests that people who are assigned to higher positions (e.g., leaders) are more likely to make self-benefiting allocations than people who are assigned to lower positions (e.g., followers). In this article, the authors investigated the proposition that these findings would be moderated by people's social value orientations. In two experimental studies, the authors assigned participants either to the role of leader or follower and assessed the participants' social value orientations. In agreement with predictions, the findings show that position effects are moderated by social value orientation. Social value orientations only affected the allocation behavior of the leaders: Proself leaders allocated more resources to themselves than did prosocial leaders. Additional analyses indicate that these effects are mediated by feelings of entitlement.     

A meta-analytic review of obesity prevention programs for children and adolescents: the skinny on interventions that work

This meta-analytic review summarizes obesity prevention programs and their effects and investigates participant, intervention, delivery, and design features associated with larger effects. A literature search identified 64 prevention programs seeking to produce weight gain prevention effects, of which 21% produced significant prevention effects that were typically pre- to post effects. Larger effects emerged for programs that targeted children and adolescents (vs. preadolescents) and females, programs that were relatively brief, programs that solely targeted weight control versus other health behaviors (e.g., smoking), programs evaluated in pilot trials, and programs wherein participants must have self-selected into the intervention. Other factors, including mandated improvements in diet and exercise, sedentary behavior reduction, delivery by trained interventionists, and parental involvement, were not associated with significantly larger effects.