The effect of sensitization and coping style on post-traumatic stress symptoms and quality of life: two longitudinal studies

The present study investigated the effects of multiple trauma exposure and coping style on post-traumatic stress symptoms and quality of life. It was hypothesized that sensitization would occur in subjects repeatedly exposed to life-threatening situations (study 1), and different coping styles would act as a resilience or facilitating factor in symptom development (study 2). The results showed that the single-exposure group revealed a decrease in trauma specific stress reactions from three weeks to four months, with a persistent reduction at 12-month follow-up, while the repeated-exposure group showed an increase in symptom reporting over the 12-month period. The same pattern emerged for perceived quality of life-measured by the General Health Questionnaire (GHQ-30). The second study revealed a correlation between scores on avoidant-focused coping style and the Impact of Event Scale-avoidance dimension, Post-traumatic Symptom Scale and GHQ-30. Furthermore, only subjects with a dominant coping style of emotion-focused or task-focused coping showed a reduction in trauma-specific symptom scores over time.     

Meaning through syntax is insufficient to explain comprehension of sentences with reduced relative clauses: comment on McKoon and Ratcliff (2003)

The authors argue that the meaning through syntax (MTS) model proposed by G. McKoon and R. Ratcliff fails to account for the comprehension of sentences with reduced relative clauses. First, the theory's core assumptions regarding verb-based event representations and how they link to constructions are incompatible with well-established analyses from the lexical semantics literature. Second, the MTS theory provides neither a principled nor a consistent account for why some reduced relatives are hard whereas others are easy. Finally, McKoon and Ratcliff's critique of constraint-based models is flawed in that sometimes they tested a nonexistent theory and sometimes they provided evidence for the constraint-based models against which they were arguing.     

STRONG MILITARY FAMILIES INTERVENTION ENHANCES PARENTING REFLECTIVITY AND REPRESENTATIONS IN FAMILIES WITH YOUNG CHILDREN

Military families face many challenges due to deployment and parental separation, and this can be especially difficult for families with young children. The Strong Military Families (SMF) intervention is for military families with young children, and consists of two versions: the Multifamily Group, and a Home‐based psychoeducational written materials program. The Multifamily Group was designed to enhance positive parenting through both educational components and in vivo feedback and support during separations and reunions between parents and children (n = 78 parents). In the present study, we examine parenting reflectivity and mental representations in mothers versus fathers in military families, service members versus civilian spouses/parenting partners, and before versus after participation in the SMF Multifamily Group and Home‐based interventions. Parenting reflectivity and mental representations were coded from the Working Model of the Child Interview (WMCI; C.H. Zeanah & D. Benoit, 1995). Results suggest that neither parenting reflectivity nor WMCI typology differs between mothers and fathers in military families, or between service members and civilian parenting partners. Furthermore, there was substantial stability in parenting reflectivity and WMCI typology from baseline to posttest, but participation in the Multifamily Group, relative to Home‐based, was associated with improvements in both parenting reflectivity and WMCI ratings from baseline to postintervention.     

Varying reinforcement magnitude on interval schedules

In Experiment 1, rats were trained on either a random-interval or a variable-interval 60-sec schedule of reinforcement, and reinforcement magnitude was varied across conditions between one and four pellets. Although the two schedules maintained different patterns of behaviour, patterns and rates of responding were not systematically affected by the variation in reinforcement magnitude. In Experiment 2, a regulated probability interval schedule that generated similar rates of reinforcement to those of the schedules of Experiment 1 was used, with the pattern of behaviour generated resembling that typical of a random-interval schedule. Changing reinforcement magnitude again produced few systematic changes in behaviour. In Experiment 3, a variable-ratio schedule was used within a procedure that otherwise resembled that of Experiments 1 and 2. Increasing the reinforcement magnitude now decreased the rates of responding, and examination of the patterns of responding showed that this came about because rates of responding were higher early in the interreinforcer interval in the one-pellet condition. These experiments demonstrate the insensitivity of behaviour under interval schedules to changes in reinforcement magnitude and suggest the operation of mechanisms different from those engaged by ratio schedules and discretetrial learning procedures.     

Chimpanzees and bonobos exhibit divergent spatial memory development

Spatial cognition and memory are critical cognitive skills underlying foraging behaviors for all primates. While the emergence of these skills has been the focus of much research on human children, little is known about ontogenetic patterns shaping spatial cognition in other species. Comparative developmental studies of nonhuman apes can illuminate which aspects of human spatial development are shared with other primates, versus which aspects are unique to our lineage. Here we present three studies examining spatial memory development in our closest living relatives, chimpanzees (Pan troglodytes) and bonobos (P. paniscus). We first compared memory in a naturalistic foraging task where apes had to recall the location of resources hidden in a large outdoor enclosure with a variety of landmarks (Studies 1 and 2). We then compared older apes using a matched memory choice paradigm (Study 3). We found that chimpanzees exhibited more accurate spatial memory than bonobos across contexts, supporting predictions from these species’ different feeding ecologies. Furthermore, chimpanzees – but not bonobos – showed developmental improvements in spatial memory, indicating that bonobos exhibit cognitive paedomorphism (delays in developmental timing) in their spatial abilities relative to chimpanzees. Together, these results indicate that the development of spatial memory may differ even between closely related species. Moreover, changes in the spatial domain can emerge during nonhuman ape ontogeny, much like some changes seen in human children.     

Manipulations of start and food locations affect navigation on a foraging task

Rats were able to search multiple food cups in a foraging task and successfully return to a fixed, but not a variable, start location. Reducing the number of food cups to be searched resulted in an improvement in performance in the variable start condition. Performance was better when only one or two food cups had to be visited but was still impaired if the food was not found in the first cup searched. Variable start locations impaired performance when only one food cup had to be searched, if that cup was moved over the table. These findings suggest that there is an interaction between memory processes and the navigational processes that allows an animal to return to its start location after a foraging trip. It appears that a fixed location for the food or the start point of a foraging trip is a necessary precondition for accurate performance.