Successive independence and behavioral contrast in a closed economy.

Two pigeons had access to multiple concurrent schedules of reinforcement for 24 hours per day in their home cages. The variable-interval schedules comprising the multiple concurrent schedules were varied across 16 conditions. In three sets of conditions, one schedule was varied while its concurrent alternative and the concurrent schedules in the other component were held constant. Behavioral contrast was observed; that is, as the rate of reinforcement arranged by the varied schedule decreased, response rates on the constant schedules typically increased. These conditions formed part of two larger sets of conditions in which the concurrent schedules in one multiple-schedule component remained constant while the concurrent schedules in the other component were varied. Successive independence was found, in that behavior allocation during the constant component did not vary as a function of the reinforcer ratios in the varied component. Successive independence between components in multiple concurrent schedules is a robust result that occurs in closed economies and under conditions that promote behavioral contrast.     

Prenatal Maternal Distress: A Risk Factor for Child Anxiety?

The deleterious association between various types of prenatal maternal psychological distress (PNMS, anxiety, depression, psychological distress, stress) and childhood anxiety symptomatology (internalizing behaviors, anxiety symptoms) has been established using both retrospective and prospective longitudinal studies across varied demographic cohorts and throughout development. Yet, the existing literature cannot claim maternal distress during pregnancy to be a specific risk factor for anxiety symptomatology, as studies utilizing such observational designs are unable to adequately account for confounding of potential genetic factors and the postnatal environment. In this review, we examine studies that attempt to minimize such confounding and thus disentangle the unique intrauterine exposure effect of varying types of PNMS on childhood anxiety symptomatology. Such methodologies include paternal versus maternal comparison studies, sibling comparisons, prenatal cross-fostering designs and timing of exposure studies (including disaster studies). Of the identified studies, findings indicate that prenatal maternal distress is likely to constitute a risk factor for anxiety symptomatology, although more studies are needed to replicate current findings in order to determine whether there are clear differences in effects across specific types of PNMS and for specific subpopulations. We review the methodological limitations and strengths of the literature prior to exploring avenues of future research and implications for theory and clinical practice.     

Integrated versus segregated accounting and the magnitude effect in temporal discounting

Temporal discounting rates in humans generally decrease as the amount of reward increases, a phenomenon known as themagnitude effect. In the present study, we examined whether temporal discounting and the magnitude effect are related to segregation of choices in terms of gains or losses for waiting for or expediting receipt of a reward. Subjects (N = 24) responded to a series of hypothetical choices about amounts of money available either immediately or after a delay. The immediate and delayed amounts either were presented as integrated amounts in the baseline condition or were segregated as differential gains or losses for choosing delayed or expedited consumption (delay and speedup conditions, respectively). Temporal discounting rates decreased in the segregated conditions, in accord with the standard discounted utility model but contrary to the hypothesis that the subjects were choosing on the basis of reward differentials in the baseline condition. The size of the magnitude effect was comparable in the baseline and the delay conditions but decreased in the speed-up condition. These results challenge explanations of the magnitude effect in terms of an increasing proportional sensitivity property of the utility function (Loewenstein & Prelec, 1992) and the hypothesis that subjects choose on the basis of differentials even when the rewards are presented as integrated amounts.     

‘He's got his father's bias’: Parental influence on weight bias in young children

Our aim was to explore the role of parents in the transmission of stereotypical body size attitudes and awareness of weight loss strategies to preschool children. Participants were 279 3‐year‐old children and their parents, who provided data at baseline and 1 year later. Parents completed self‐report body size attitude and dieting measures. Child weight bias and awareness of weight loss strategies were assessed through interview. Over time, negative associations with large bodies and awareness of weight loss strategies increased. Fathers’ attitudes prospectively predicted boys’ weight bias and awareness of weight loss strategies. Among girls, parental attitudes were less predictive. Findings confirm the importance of fathers in the development of boys’ body attitudes and inform prevention programmes.     

Overconcern with weight and shape is not the same as body dissatisfaction: evidence from a prospective study of pre-adolescent boys and girls

Overconcern with weight and shape and body dissatisfaction have both emerged as significant predictors of disordered eating. However, it is unclear how these constructs relate to each other, and if each has different antecedents and consequences. This study aimed to identify prospective predictors of each construct and to determine their relative importance in predicting dietary restraint and binge eating. Eight- to 13-year-old boys and girls (N = 259) were assessed at baseline and one-year follow-up, using a range of measures that included the Child Eating Disorder Examination. Psychosocial variables predicted overconcern with weight and shape whilst objective weight predicted body dissatisfaction. Body dissatisfaction and weight and shape concern predicted restraint, and weight and shape concern and restraint predicted binge eating. Findings provide support for the theoretical differences between body dissatisfaction and overconcern with weight and shape, and highlight the importance of focusing on specific body image variables.     

Stories of the young and the old: personal continuity and narrative identity

This study examined narrative identity in 2 groups of participants who were younger (ages ranging from late adolescence through young adulthood) and older (over the age of 65 years). Participants completed an extensive interview in which they reported three self-defining memories. Interviews were coded for several characteristics of autobiographical reasoning: self-event connections representing self-stability or self-change, event-event connections, reflective processing, and thematic coherence. Results showed that the older and younger groups were not different in terms of the frequencies of self-event connections or the levels of reflective processing. However, in comparison with the younger group, the older group had more thematic coherence and more stories representing stability, whereas the younger group had more stories representing change. Gender differences also emerged, suggesting that females may have an advantage in the development of narrative identity. Results are discussed in terms of the different ways to represent narrative identity at 2 ends of the life span.