Optimal decision making in neural inhibition models

In their influential Psychological Review article, Bogacz, Brown, Moehlis, Holmes, and Cohen (2006) discussed optimal decision making as accomplished by the drift diffusion model (DDM). The authors showed that neural inhibition models, such as the leaky competing accumulator model (LCA) and the feedforward inhibition model (FFI), can mimic the DDM and accomplish optimal decision making. Here we show that these conclusions depend on how the models handle negative activation values and (for the LCA) across-trial variability in response conservativeness. Negative neural activations are undesirable for both neurophysiological and mathematical reasons. However, when negative activations are truncated to 0, the equivalence to the DDM is lost. Simulations show that this concern has practical ramifications: the DDM generally outperforms truncated versions of the LCA and the FFI, and the parameter estimates from the neural models can no longer be mapped onto those of the DDM in a simple fashion. We show that for both models, truncation may be avoided by assuming a baseline activity for each accumulator. This solution allows the LCA to approximate the DDM and the FFI to be identical to the DDM.     

Forgiveness results from integrating information about relationship value and exploitation risk

Exploitation is a fact of life for social organisms, and natural selection gives rise to revenge mechanisms that are designed to deter such exploitations. However, humans may also possess cognitive forgiveness mechanisms designed to promote the restoration of valuable social relationships following exploitation. In the current article, the authors test the hypothesis that decisions about forgiveness result from a computational system that combines information about relationship value and exploitation risk to produce decisions about whom to forgive following interpersonal offenses. The authors examined the independent and interactive effects of relationship value and exploitation risk across two studies. In Study 1, controlling for other constructs related to forgiveness, the authors assessed relationship value and exploitation risk. In Study 2, participants experienced experimental manipulations of relationship value and exploitation risk. Across studies, using hypothetical and actual offenses and varied forgiveness measures, the combination of low exploitation risk and high relationship value predicted the greatest forgiveness.     

Collectivistic Self‐Construal and Forgiveness

This study tested a theoretical model of the relationship between collectivism and forgiveness. Participants (N= 298) completed measures of collectivistic self‐construal, forgiveness, and forgiveness‐related constructs. A collectivistic self‐construal was related to understanding forgiveness as an interpersonal process that involved reconciliation. Individuals with more collectivistic views reported higher trait forgivingness, which predicted the tendency to respond to specific offenses with decisional rather than emotional forgiveness. Individuals with a more collectivistic self‐construal may place more value on interpersonal harmony, reconciliation, and decisions to forgive rather than emotional peace. Implications suggest that counselors understand issues of conflict, hurts, and forgiveness within an assessment of clients’ self‐construal.     

Approach and avoidance motivation as predictors of pro-relationship behaviors

Pro-relationship behaviors, such as willingness to sacrifice, are assumed to be driven by both approach and avoidance motivation. However, this assumption has not been directly tested. In two studies, we examined how individual differences in approach and avoidance motivation predicted pro-relationship behavior. In Study 1, avoidance (but not approach) motivation uniquely predicted sacrificial behavior. In Study 2, sacrificing was uniquely predicted by avoidance motivation, whereas accommodation was uniquely predicted by approach motivation. These data suggest that although both sacrificing and accommodation are pro-relationship behaviors, they are driven by different motivational systems, which in turn may result in different long-term relational outcomes.     

A bayesian optimal foraging model of human visual search

Real-world visual searches often contain a variable and unknown number of targets. Such searches present difficult metacognitive challenges, as searchers must decide when to stop looking for additional targets, which results in high miss rates in multiple-target searches. In the study reported here, we quantified human strategies in multiple-target search via an ecological optimal foraging model and investigated whether searchers adapt their strategies to complex target-distribution statistics. Separate groups of individuals searched displays with the number of targets per trial sampled from different geometric distributions but with the same overall target prevalence. As predicted by optimal foraging theory, results showed that individuals searched longer when they expected more targets to be present and adjusted their expectations on-line during each search by taking into account the higher-order, across-trial target distributions. However, compared with modeled ideal observers, participants systematically responded as if the target distribution were more uniform than it was, which suggests that training could improve multiple-target search performance.     

Inhibiting PKMζ reveals dorsal lateral and dorsal medial striatum store the different memories needed to support adaptive behavior

Evidence suggests that two regions of the striatum contribute differential support to instrumental response selection. The dorsomedial striatum (DMS) is thought to support expectancy-mediated actions, and the dorsolateral striatum (DLS) is thought to support habits. Currently it is unclear whether these regions store task-relevant information or just coordinate the learning and retention of these solutions by other brain regions. To address this issue, we developed a two-lever concurrent variable-interval reinforcement operant conditioning task and used it to assess the trained rat's sensitivity to contingency shifts. Consistent with the view that these two regions make different contributions to actions and habits, injecting the NMDA antagonist DL-AP5 into the DMS just prior to the shift impaired the rat's performance but enhanced performance when injected into the DLS. To determine if these regions support memory content, we first trained rats on a biased concurrent schedule (Lever 1: VI 40" and Lever 2: VI 10"). With the intent of "erasing" the memory content stored in striatum, after this training we inhibited the putative memory-maintenance protein kinase C isozyme protein kinase Mζ (PKMζ). Infusing zeta inhibitory peptide (ZIP) into the DLS enhanced the rat's ability to adapt to the contingency shift 2 d later, whereas injecting it into the DMS had the opposite effect. Infusing GluR2(3Y) into the DMS 1 h before ZIP infusions prevented ZIP from impairing the rat's sensitivity to the contingency shift. These results support the hypothesis that the DMS stores information needed to support actions and the DLS stores information needed to support habits.     

An item response theory analysis of the Problem Gambling Severity Index

Increases in the availability of gambling heighten the need for a short screening measure of problem gambling. The Problem Gambling Severity Index (PGSI) is a brief measure that allows for the assessment of characteristics of gambling behavior and severity and its consequences. The authors evaluate the psychometric properties of the PGSI using item response theory methods in a representative sample of the urban adult population in South Africa (N = 3,000). The PGSI items were evaluated for differential item functioning (DIF) due to language translation. DIF was not detected. The PGSI was found to be unidimensional, and use of the nominal categories model provided additional information at higher values of the underlying construct relative to a simpler binary model. This study contributes to the growing literature supporting the PGSI as the screen of choice for assessing gambling problems in the general population.     

Do Deaf Individuals’ Dating Scripts Follow the Traditional Sexual Script?

The current study investigated Deaf individuals’ dating expectations. Prior research on dating expectations has identified three common scenes: initiation/meeting, activities, and outcomes/conclusions. Participants were asked to report their expectations for each scene on a typical date. Talking was the most frequently occurring initiation activity. Dinner and a movie were among the top date activities in the activities scene. Activities were often reported as group gatherings. Dating outcomes included a good night kiss and making plans for another date. These expectations do not match prior research with hearing participants where the Traditional Sexual Script could be identified. Comparisons and suggestions for future research are discussed.