A kestrel without hooked beak and talons is not a kestrel for the red-backed shrike (Lanius collurio)

Animal Cognition - Birds are strongly motivated to recognize various predators to secure survival and reproductive success. Thus, predator recognition provides a useful tool for the investigation...     

Spontaneous inferential processing while reading interleaved expository texts enables learners to discover the underlying regularities

Recent studies on text sequencing found learning advantages of interleaving over blocking in terms of high‐level inferences. We conducted a 2 × 2 × 2 mixed factorial experiment with college students (n = 117) by manipulating text sequence (interleaved vs. blocked) and self‐questioning activity while reading (spontaneous vs. prompted) between subjects and testing delay (immediately vs. 1‐week delay) within subjects. Results revealed that students are spontaneously engaged in self‐questioning and inferential processing while reading an interleaved text. Students who were spontaneously engaged while reading an interleaved text outperformed their counterparts in all other conditions in the immediate and delayed test on comparative reasoning, inductive reasoning, and memorization of factual details. The learning advantages were mediated by inductive inferences made while reading an interleaved text. Results support the discriminative contrast view that readers are encouraged to discover the underlying regularities when differences and similarities among categories are accentuated by their juxtaposition.     

Task switching: effects of practice on switch and mixing costs

In the task-switching paradigm, mixing costs indicate the performance costs to mix two different tasks, while switch costs indicate the performance costs to switch between two sequentially presented tasks. Applying tasks with bivalent stimuli and responses, many studies demonstrated substantial mixing and switch costs and a reduction of these costs as a result of practice. The present study investigates whether extensive practice of a task-switching situation including tasks with univalent stimuli eliminates these costs. Participants practiced switching between a visual and an auditory task. These tasks were chosen because they had shown eliminated performance costs in a comparable dual-task practice study (Schumacher et al. Psychol Sci 12:101–108, 2001). Participants either performed the tasks with univalent responses (i.e., visual-manual and auditory-verbal stimulus–response mappings) or bivalent responses (i.e., visual-manual and auditory-manual stimulus–response mappings). Both valence conditions revealed substantial mixing and switch costs at the beginning of practice, yet, mixing costs were largely eliminated after eight practice sessions while switch costs were still existent.     

The More the Better? Effects of Training,Experience and Information Amount in Legal Judgments

In an experimental study involving German lay judges, law students and controls, effects of legal training and experience as well as information amount on legal judgments was investigated. In a three (legal knowledge: legal training versus legal experience versus controls) x two (information amount: high versus low) between‐subjects design, 137 participants judged the premeditation of a perpetrator in eight real‐world cases decided by the German Federal Court of Justice. Judgment congruency with the Court's ruling increased with legal training, but official lay judges showed lower congruency compared with student controls. Additionally, legal training and experience corresponded with higher confidence. Emotional reactions to the legal cases were stronger when more information was given for individuals without legal training but decreased for individuals with training. An information‐processing perspective to explain the observed differences in legal judgments is advanced, and the issue of using untrained individuals in the legal decision making process is discussed. Copyright © 2011 John Wiley & Sons, Ltd.     

Kv4 potassium channels modulate hippocampal EPSP-spike potentiation and spatial memory in rats

Kv4 channels regulate the backpropagation of action potentials (b-AP) and have been implicated in the modulation of long-term potentiation (LTP). Here we showed that blockade of Kv4 channels by the scorpion toxin AmmTX3 impaired reference memory in a radial maze task. In vivo, AmmTX3 intracerebroventricular (i.c.v.) infusion increased and stabilized the EPSP-spike (E-S) component of LTP in the dentate gyrus (DG), with no effect on basal transmission or short-term plasticity. This increase in E-S potentiation duration could result from the combination of an increase in excitability of DG granular cells with a reduction of GABAergic inhibition, leading to a strong reduction of input specificity. Radioactive in situ hybridization (ISH) was used to evaluate the amounts of Kv4.2 and Kv4.3 mRNA in brain structures at different stages of a spatial learning task in naive, pseudoconditioned, and conditioned rats. Significant differences in Kv4.2 and Kv4.3 mRNA levels were observed between conditioned and pseudoconditioned rats. Kv4.2 and Kv4.3 mRNA levels were transiently up-regulated in the striatum, nucleus accumbens, retrosplenial, and cingulate cortices during early stages of learning, suggesting an involvement in the switch from egocentric to allocentric strategies. Spatial learning performance was positively correlated with the levels of Kv4.2 and Kv4.3 mRNAs in several of these brain structures. Altogether our findings suggest that Kv4 channels could increase the signal-to-noise ratio during information acquisition, thereby allowing a better encoding of the memory trace.     

Predicting posttraumatic growth among Hurricane Katrina survivors living with HIV: the role of self-efficacy,social support,and PTSD symptoms

Abstract

The study tested the model of adaptation after trauma by Benight and Bandura (2004) indicating that posttraumatic recovery may be predicted directly by coping self-efficacy (CSE) and indirectly by social support. These relations were investigated in the context of posttraumatic growth (PTG) among Hurricane Katrina survivors living with HIV. Additionally, it was hypothesized that among individuals with more intensive Posttraumatic Stress Disorder (PTSD) symptoms, those with strong CSE would experience the strongest PTG. Cross-sectional data were collected among 90 patients with HIV who reinitiated care at the HIV outpatient clinic. Questionnaires were administered approximately 14 months after the hurricane. Higher CSE was related to higher PTG among the survivors who suffered from more intensive PTSD symptoms. Received social support was directly related to only one index of PTG, relating to others. Furthermore, although there was a significant relationship between social support and CSE, the indirect conditional effect of received social support on PTG was not confirmed. Similar results were obtained across the indices of PTG, controlling for the level of exposure to hurricane-related trauma. Cross-sectional design and convenience character of the sample warrants replications.     

Abnormal Neural Sensitivity to Monetary Gains Versus Losses Among Adolescents at Risk for Depression

Major depressive disorder aggregates within families, although the mechanisms of transfer across generations are not well understood. In light of converging biological and behavioral evidence that depressive symptoms are associated with impaired reward processing, we examined whether adolescent girls with a parental history of depression would also exhibit abnormal reward sensitivity. We performed a negative mood induction and then recorded the feedback negativity, a neural index of reward processing, while individuals completed a gambling task. High-risk adolescents reported greater sadness following the mood induction compared to low-risk adolescents. Among the high-risk group, sadness was strongly associated with a blunted feedback negativity, even after controlling for baseline mood and trait neuroticism. This suggests that high-risk adolescents are more reactive to negative stimuli, which significantly alter neural sensitivity to monetary gains and losses. The feedback negativity might be used to identify information processing abnormalities in high-risk populations prior to the onset of a major depressive episode.     

Self-regulation of priming effects on behavior

In three experiments, we tested whether people can protect their ongoing goal pursuits from antagonistic priming effects by using if-then plans (i.e., implementation intentions). In Experiment 1, concept priming did not influence lexical decision time for a critical stimulus when participants had formed if-then plans to make fast responses to that stimulus. In Experiment 2, participants who were primed with a prosocial goal allowed a confederate who asked for help to interrupt their work on a focal task for a longer time if they had merely formed goal intentions to perform well than if they had also formed implementation intentions for concentrating on the task. In Experiment 3, priming the goal of being fast increased driving speed and errors for participants who had formed mere goal intentions to drive only as fast as safety allowed or who had formed no goal intentions, whereas the driving of participants who had formed such goal intentions as well as implementation intentions showed no such priming effects. Our findings indicate that implementation intentions are an effective self-regulatory tool for shielding actions from disruptive concept- or goal-priming effects.     

A Categorical Approach to Probability Theory

First, we discuss basic probability notions from the viewpoint of category theory. Our approach is based on the following four “sine quibus non” conditions: 1. (elementary) category theory is efficient (and suffices); 2. random variables, observables, probability measures, and states are morphisms; 3. classical probability theory and fuzzy probability theory in the sense of S. Gudder and S. Bugajski are special cases of a more general model; 4. a good model allows natural modifications. Second, we show that the category ID of D-posets of fuzzy sets and sequentially continuous D-homomorphisms allows to characterize the passage from classical to fuzzy events as the minimal generalization having nontrivial quantum character: a degenerated state can be transported to a nondegenerated one. Third, we describe a general model of probability theory based on the category ID so that the classical and fuzzy probability theories become special cases and the model allows natural modifications. Finally, we present a modification in which the closed unit interval [0,1] as the domain of traditional states is replaced by a suitable simplex.     

Trait anxiety and dynamic adjustments in conflict processing

Recently, it has been assumed that high- and low-trait-anxious subjects differ in the way they use fundamental cognitive control mechanisms. The present study was designed to further elucidate this topic by focusing on trial-to-trial adjustments in neuronal correlates of conflict processing. An electroencephalogram was recorded while subjects (N=71) performed a gender discrimination version of the Stroop task. The conflict-related N400 of the ERP was influenced by an interaction between trait anxiety and previous trial context: An additional negative-going deflection in the N400 range was observed when the target—distractor pairing of the directly preceding trial was incongruent, but only in highly anxious subjects. Thus, highly anxious subjects appear to more strongly engage neuronal modules involved in conflict monitoring when previously exposed to a high stimulus-response conflict. These results indicate that trait anxiety is crucially linked to the way the cognitive system dynamically adapts to recent demands.