Changing the rate and hippocampal dependence of trace eyeblink conditioning: slow learning enhances survival of new neurons

Trace eyeblink conditioning in which a conditioned stimulus and unconditioned stimulus are separated by a gap, is hippocampal dependent and can rescue new neurons in the adult dentate gyrus from death (e.g., Beylin et al., 2001; Gould et al., 1999). Tasks requiring more training trials for reliable expression of the conditioned response are most effective in enhancing survival of neurons (Waddell & Shors, 2008). To dissociate hippocampal dependence from acquisition rate, we facilitated hippocampal-dependent trace eyeblink conditioning in two ways: a shorter trace interval and signaling the intertrial interval with a post-US cue. Trace conditioning with a shorter trace interval (250ms) requires an intact hippocampus, and acquisition is faster relative to rats trained with a 500ms trace interval (e.g., Weiss et al., 1999). Using excitotoxic hippocampal lesions, we confirmed that eyeblink conditioning with the 250 or 500ms trace interval is hippocampal dependent. However, training with the post-US cue was not hippocampal dependent. The majority of lesion rats in this condition reached criterion of conditioned responding. To determine whether hippocampal dependence is sufficient to rescue adult-generated neurons in the dentate gyrus, rats were injected with BrdU and trained in one of the three trace eyeblink arrangements one week later. Of these training procedures, only the 500ms trace interval enhanced survival of new cells; acquisition of this task proceeded slowly relative to the 250ms and post-US cue conditions. These data demonstrate that rate of acquisition and not hippocampal dependence determines the impact of learning on adult neurogenesis.     

Can children resist making interpretations when uncertain?

In two experiments, we examined young children's ability to delay a response to ambiguous input. In Experiment 1, 5- and 6-year-olds performed as poorly when they needed to choose between basing an interpretation on ambiguous input and delaying an interpretation as when making explicit evaluations of knowledge, whereas 7- and 8-year-olds found the former task easy. In Experiment 2, 5- and 6-year-olds performed well on a task that required delaying a response but removed the need to decide between strategies. We discuss children's difficulty with ambiguity in terms of the decision-making demands made by different procedures. These demands appear to cause particular problems for young children.     

Mindfulness,General Trust,and Social Support Among Trauma-Exposed College Students

The purpose of the present study was to examine whether mindfulness predicts general trust and social support among trauma-exposed college students, as well as to examine the potential moderating effect of posttraumatic stress on these relationships. Participants consisted of 536 trauma-exposed college students attending a public university in the southeast United States. After controlling for PTSD symptoms and type of trauma, mindfulness was positively associated with general trust and social support at low and mean levels of PTSD symptomatology; however, the relationships between mindfulness and these variables were nonsignificant at high levels of PTSD symptomatology.     

Comparing observational software with paper and pencil for time-sampled data: A field test of Interval Manager (INTMAN)

In this article, we describe the Interval Manager (INTMAN) software system for collecting timesampled observational data and present a preliminary application comparing the program with a traditional paper-and-pencil method. INTMAN is a computer-assisted alternative to traditional paper-and-pencil methods for collecting fixed interval time-sampled observational data. The INTMAN data collection software runs on Pocket PC handheld computers and includes a desktop application for Microsoft Windows that is used for data analysis. Standard analysis options include modified frequencies, percent of intervals, conditional probabilities, and kappa agreement matrices and values. INTMAN and a standardized paper-and-pencil method were compared under identical conditions on five dimensions: setup time, duration of data entry, duration of interobserver agreement calculations, accuracy, and cost. Overall, the computer-assisted program was a more efficient and accurate data collection system for time-sampled data than the traditional method.     

What do I think you're doing? Action identification and mind attribution

The authors examined how a perceiver's identification of a target person's actions co-varies with attributions of mind to the target. The authors found in Study 1 that the attribution of intentionality and cognition to a target was associated with identifying the target's action in terms of high-level effects rather than low-level details. In Study 2, both action identification and mind attribution were greater for a liked target, and in Study 3, they were reduced for a target suffering misfortune. In Study 4, it was again found that action identification and mind attribution were greater for a liked target, but like that for the self or a liked other, positive actions were identified at higher levels than negative actions, with the reverse being true for disliked others. In Study 5, the authors found that instructing participants to adopt the target's perspective did not affect mind attribution but did lead to higher level identifications of the target's actions.     

Universal sex differences in the desire for sexual variety: tests from 52 nations, 6 continents,and 13 islands

Evolutionary psychologists have hypothesized that men and women possess both long-term and short-term mating strategies, with men's short-term strategy differentially rooted in the desire for sexual variety. In this article, findings from a cross-cultural survey of 16,288 people across 10 major world regions (including North America, South America, Western Europe, Eastern Europe, Southern Europe, Middle East, Africa, Oceania, South/Southeast Asia, and East Asia) demonstrate that sex differences in the desire for sexual variety are culturally universal throughout these world regions. Sex differences were evident regardless of whether mean, median, distributional, or categorical indexes of sexual differentiation were evaluated. Sex differences were evident regardless of the measures used to evaluate them. Among contemporary theories of human mating, pluralistic approaches that hypothesize sex differences in the evolved design of short-term mating provide the most compelling account of these robust empirical findings.