Overtraining,Extinction, and Shift Learning in Matching-to-Sample Discriminations in Rats

The Psychological Record - The present experiment examined the influence of overtraining on the nonshift and reversal shift of a matching-to-sample (MTS) discrimination. Rats were trained to...     

Case study of a one‐sided attack by multiple troop members on a nontroop adolescent male and the death of Japanese macaques (Macaca fuscata)

An adolescent wild male Japanese macaque (Macaca fuscata), following Kinkazan A troop, was attacked one‐sidedly by multiple members of the troop. The victim was identified as PI, and was estimated to be seven±one year old. The aggressive interaction was recorded by video camera until the end. Although at least 16 troop members approached PI more than once, only three males (one adult, two adolescents) of A troop attacked him. PI kept crouching throughout the attack, then escaped to the shore and dived into the sea. The interaction continued for more than one hour. PI was found dead a few hours after the end of interaction. The damage caused by the assailants was not the direct cause of PI's death; it was due to hypothermia caused by drifting in the sea. PI's life history was reconstructed from past records. PI was a normal adolescent male who migrated from an all‐male group around B₁ troop and started ranging around A troop. The aggressive interaction is believed to be a typical example of conflict between troop males and a nontroop male. The interaction period was very long compared with previous reports on such conflicts among Japanese macaques. PI kept crouching in open areas, exposing himself as a potential competitor for the resources of the troop, and did not show any submissive or reconciliatory behavior toward the troop males. This may be why the troop males did not stop the attack. Aggr. Behav. 35:334–341, 2009. © 2009 Wiley‐Liss, Inc.     

Variable coordination of eye and head movements during the early development of attention: A longitudinal study of infants aged 12–36 months

This longitudinal study investigated the effects of attentional development on peripheral stimulus localization by analyzing the eye and head movements of toddlers as they matured from 12 to 36 months. On each trial of an experiment, a central fixation point and a 30° peripheral stimulus were presented, such that in the gap condition the fixation disappeared 300 ms before the peripheral stimulus, whereas in the no-overlap condition it disappeared simultaneously as the peripheral stimulus, and in the overlap condition the fixation remained present when the peripheral target occurred. Results showed that eye and head movement latencies were highly correlated in all conditions and ages. However, at 12 months, head movements were as fast as eye movements, whereas during the subsequent development, eye movements became increasingly faster than head movements. These findings are indicative of a transition between 12 and 36 months due either to a change in attentional control, or to changes in the size of the visual field in which only eye movements occur.     

Individual differences in disengagement of fixation and temperament: Longitudinal research on toddlers

It has been suggested that a shift occurs in the brain's control system from the orienting network in infancy to the executive network by the age of 3–4 years; however, there has been little empirical evidence of this shift during toddlerhood. Therefore, the present study examined how the orienting system in infancy is related to an effortful control system at a later age. Children were assessed longitudinally at 12, 18, 24, and 36 months of age, using a gap-overlap task in which dynamic geometrical-shape stimuli were presented. Parents completed temperament questionnaires about the children at each age. A delayed-gratification task was also given to 36-month-olds. Overall, saccadic latencies in the gap-overlap task were significantly faster at 36 months. At all ages, responses were slower during overlap trials than during gap or no-overlap trials. Longer latencies in the overlap condition were associated with low temperamental orienting/regulation scores at 12 months but with high effortful control scores at 18 and 24 months. The associations at 18 and 24 months are thought to represent a genuine positive association between effortful control and sustained and focused attention.     

Theorema: Towards computer-aided mathematical theory exploration

Theorema is a project that aims at supporting the entire process of mathematical theory exploration within one coherent logic and software system. This survey paper illustrates the style of Theorema-supported mathematical theory exploration by a case study (the automated synthesis of an algorithm for the construction of Gröbner Bases) and gives an overview on some reasoners and organizational tools for theory exploration developed in the Theorema project.     

Mechanism of Stimulus Classes Formation in Concurrent Discriminations in Rats

The Psychological Record - The two present experiments examined a premise of stimulus classes formation between discriminative stimuli in rats. Rats were concurrently trained on two discriminations...     

Culture, emotion regulation, and adjustment

This article reports differences across 23 countries on 2 processes of emotion regulation--reappraisal and suppression. Cultural dimensions were correlated with country means on both and the relationship between them. Cultures that emphasized the maintenance of social order--that is, those that were long-term oriented and valued embeddedness and hierarchy--tended to have higher scores on suppression, and reappraisal and suppression tended to be positively correlated. In contrast, cultures that minimized the maintenance of social order and valued individual Affective Autonomy and Egalitarianism tended to have lower scores on Suppression, and Reappraisal and Suppression tended to be negatively correlated. Moreover, country-level emotion regulation was significantly correlated with country-level indices of both positive and negative adjustment.     

Reversal Learning in Conditional Discriminations Is Not Controlled by Reinforcer Density

The Psychological Record - Three experiments have examined whether a whole-partial reversal effect is due to shift in reinforcement density across phases, between whole and partial reversal in both...     

Computational models of inductive reasoning using a statistical analysis of a Japanese corpus

Existing computational models of human inductive reasoning have been constructed based on psychological evaluations concerning the similarities or relationships between entities. However, the costs involved in collecting psychological evaluations for the sheer number of entities that exist mean that they are prohibitively impractical. In order to avoid this problem, the present article examines three types of models: a category-based neural network model, a category-based Bayesian model, and a feature-based neural network model. These models utilize the results of a statistical analysis of a Japanese corpus computing co-occurrence probabilities for word pairs, rather than using psychological evaluations. Argument strength ratings collected by a psychological experiment were found to correlate well with simulations for the category-based neural network model.     

Overtraining, extinction and shift learning in a concurrent discrimination in rats

Two experiments examined the influence of overtraining on the reversal of a concurrent discrimination. After rats are trained to criterion on two different discriminations in the same apparatus, the reversal of one of these proceeds more rapidly than when both are reversed. If the reversal is conducted after overtraining on the original discriminations, then the opposite pattern of results is observed. That is, learning about the reversal of both discriminations is more rapid than when only a single discrimination is reversed. Experiment 1 replicated this effect and suggested that it is not caused by differences in the rate of extinction during reversal learning. In order to test a cue-association account for these findings, Experiment 2 examined the effect of exchanging the negative stimuli of a concurrent discrimination. This manipulation had a disruptive influence on performance, but only when subjects were not overtrained on the original discrimination.