An experimental analysis of optimal foraging behaviour in patchy environments

A series of experiments was designed to explore the cognitive mechanisms involved in optimal foraging models by using the behavioural controls of operant methodology. Rats were trained to press one of two levers to obtain reinforcement on a progressive variable-interval schedule, which modelled food patch depletion; the schedule was reset by pressing the other lever. Thus both duration (residence time in a patch) and rate-related (interval before and after the final reward) measures were obtained. Experiment 1, which manipulated environmental stability and quality, and Experiment 2, which varied travel time between patches, found results that supported the marginal value theorem (Charnov, 1976) and suggested that rats adjust capture rate to the environment average by monitoring the length of the interval between rewards. Experiment 3 modelled the clumping of food items and found that capture rate was now adjusted by adoption of a fixed giving-up time. Finally, Experiments 4a and 4b ruled out a time expectancy hypothesis by manipulating the number of food clumps and the series of inter-reinforcement intervals. Overall the experiments demonstrate the value of modelling foraging strategies in operant apparatus, and suggest that rats adopt rate predictive strategies when deciding to switch patches.     

The role of maladaptive beliefs in cognitive-behavioral therapy: Evidence from social anxiety disorder

Beliefs that are negatively biased, inaccurate, and rigid are thought to play a key role in the mood and anxiety disorders. Our goal in this study was to examine whether a change in maladaptive beliefs mediated the outcome of individual cognitive-behavioral therapy (CBT) for social anxiety disorder (SAD). In a sample of 47 individuals with SAD receiving CBT, we measured maladaptive interpersonal beliefs as well as emotional and behavioral components of social anxiety, both at baseline and after treatment completion. We found that (a) maladaptive interpersonal beliefs were associated with social anxiety at baseline and treatment completion; (b) maladaptive interpersonal beliefs were significantly reduced from baseline to treatment completion; and (c) treatment-related reductions in maladaptive interpersonal beliefs fully accounted for reductions in social anxiety after CBT. These results extend the literature by providing support for cognitive models of mental disorders, broadly, and SAD, specifically.     

A longitudinal test of the bi-directional relations between avoidance coping and PTSD severity during and after PTSD treatment

Avoidance coping and symptoms of posttraumatic stress disorder (PTSD) covary. However, relatively little research has examined the bi-directional relation between these constructs among individuals in treatment for PTSD. The current longitudinal study examined the reciprocal associations between avoidance coping and PTSD symptom severity during and after residential PTSD treatment among a sample of 1073 military veterans (88.9% male; M_age = 52.39 years) with chronic, treatment-resistant PTSD. Greater avoidance coping at intake predicted more severe PTSD symptoms at discharge, and severity of PTSD symptoms at discharge predicted increased avoidance at follow-up. Conversely, PTSD symptom severity at intake was not related to avoidance coping at discharge, and in turn avoidance coping at discharge was not related to PTSD symptom severity at follow-up. These findings offer a number of important clinical implications including evidence suggesting avoidance may predict poorer treatment response among individuals seeking treatment for chronic PTSD, and that greater end-of-treatment PTSD symptom severity may predict increased avoidance following treatment.     

The psychology of markets vs. hierarchies: The procedural fairness of alternative allocation procedures for benefits and burdens

This paper reports two studies examining the influence of social context on judgments about the fairness and desirability of two allocation mechanisms — markets and hierarchies. Two allocation contexts are compared: distributing benefits and burdens. The results show that people prefer to allocate burdens through markets and benefits through hierarchies. In both cases desirability is linked to procedural fairness, suggesting that people always prefer to use the fairer procedure for allocation, but view different procedures as fairer in these different contexts. Procedural fairness judgments were found to be linked to respondents' judgments about the impact of using different procedures to make allocations in each context, with people in each case preferring the procedure that they believe will have the most positive impact upon group cohesion. These findings suggest that what is construed as a fair procedure in one social context is not the same as what is construed as a fair procedure in another social context.     

Changes in spinal excitability during dual task performance

ABSTRACT The authors investigated how the nervous system responds to dual task performance. Because dual tasking is associated with greater postural challenges, it was hypothesized that spinal excitability would be reduced when simultaneously performing 2 tasks. For this experiment, participants maintained a lying or standing posture with or without performing a concurrent cognitive task (i.e., reacting to an auditory tone). Spinal excitability was assessed by eliciting the soleus Hoffmann reflex (H-reflex). Results indicated that the H-reflex was 6.4 ± 2.3% smaller (p = .011) when dual compared to single tasking. The reduced H-reflex amplitude, indicating a depressed spinal excitability, when dual tasking is suggested to reflect a neural strategy that individuals adopt to maintain postural stability when cognitive resources are divided between 2 concurrent tasks.     

Triggering self-presentation efforts outside of people's conscious awareness

Three studies utilized priming techniques to examine whether self-presentations can be activated without conscious awareness. The results across all experiments consistently demonstrated nonconscious self-presentation effects, in that people were unaware that their self-presentations were triggered automatically and that their self-presentations were comparable to participants who were explicitly instructed to self-present. The findings are novel because they are the first to demonstrate that self-presentations can be triggered without conscious awareness in a manner similar to self-presentations that are strategically selected. In addition, the results help undermine the common misconception that self-presentation typically involves conscious deliberation, pretense, or outright deception.     

Facets of Emotional Clarity and Suspiciousness

In a college student sample, we explored the relations between individual differences in facets of emotional clarity and suspiciousness. Previous theory and research has treated emotional clarity as a one-dimensional construct. Boden and Berenbaum (2011) proposed that a second facet of emotional clarity, source awareness (a general understanding of the cause of their emotions), could be distinguished from type awareness (a general understanding of the type of emotions [anger, fear] experienced). We found that source and type awareness were incrementally, inversely associated with suspiciousness when statistically accounting for the extent to which emotions are attended to, and gender. Additionally, source awareness significantly predicted suspiciousness after accounting for anger, anxious arousal, and social anxiety, whereas type awareness did not. Findings are consistent with the hypothesis that, among individuals with low source and type awareness, suspicious beliefs are formed to make sense of and explain emotional arousal.