The role of imagination in facilitating deductive reasoning in 2-, 3- and 4-year-olds.

When 4- and 6-year-olds are cued to use their imagination, they can overcome the belief bias effect and demonstrate deductive reasoning ability on syllogisms containing contrary-to-fact material. This study tested whether 2- and 3-year-olds could also reason with incongruent syllogisms when encouraged to use their imagination. Eighty-four 2-, 3- and 4-year-olds were randomly assigned to one of four conditions: no cue, word cue, fantasy planet or imagery. Children were then presented with six syllogistic reasoning problems containing incongruent information. In the imagination conditions, 2- and 3-year-olds performed as competently as 4-year-olds. The findings are discussed in relation to other research which suggests that under certain circumstances 2- and 3-year-olds have the capacity for counterfactual thinking.     

A quantitative interresponse-time analysis of DRL performance differentiates similar effects of the antidepressant desipramine and the novel anxiolytic gepirone.

We describe an interresponse-time analysis of performance on a differential-reinforcement-of-low-rate 72-s schedule. This analysis compares the obtained interresponse-time distribution of individual rats to a corresponding random interresponse-time distribution. The random interresponse-time distribution is a negative exponential probability function; it predicts the relative distribution of interresponse times if the rat emitted the same number of responses randomly (i.e., with a constant probability) with respect to time. The analysis provides quantitative measures of peak location and dispersion of the interresponse times toward random performance. In Experiment 1, an unexpected outcome of this analysis was that the rats would have obtained more reinforcers had they responded at the same rate but randomly. Based on the interresponse-time analysis in Experiment 1, it was shown that rats trained on the differential-reinforcement-of-low-rate 72-s schedule could increase the number of reinforcers obtained in two ways: first, by a coherent shift of the interresponse-time distribution toward longer durations and, second, by dispersal of the interresponse times toward a random interresponse-time distribution. Experiment 2 applied the analysis described in Experiment 1 to the effects of desipramine and gepirone. Both drugs decreased response rate and increased reinforcement rate, but their effects on the distribution of interresponse times were different. The increase in reinforcement rate observed with desipramine was accompanied by a coherent shift of the reinforcement rate observed with gepirone was accompanied by dispersal of the interresponse-time distribution toward the random negative exponential prediction.     

A right-ear advantage in monotic shadowing

Lists of 30 monosyllabic words drawn at random with replacement from a set of 69 were presented monotically to the right or left ear of 28 subjects for immediate repetition (shadowing) at a rate of 120 words per minute. Each subject shadowed 40 lists. A right-ear advantage was found over the first 1.5 blocks (15 lists) but not for the remaining 2.5 blocks (25 lists). The results are related to previous investigations of monotic and dichotic listening, and are explained by a set (bias) in attention or response which favours the right ear and declines with practice.     

DRL interresponse-time distributions: quantification by peak deviation analysis.

Peak deviation analysis is a quantitative technique for characterizing interresponse-time distributions that result from training on differential-reinforcement-of-low-rate schedules of reinforcement. It compares each rat's obtained interresponse-time distribution to the corresponding negative exponential distribution that would have occurred if the rat had emitted the same number of responses randomly in time, at the same rate. The comparison of the obtained distributions with corresponding negative exponential distributions provides the basis for computing three standardized metrics (burst ratio, peak location, and peak area) that quantitatively characterize the profile of the obtained interresponse-time distributions. In Experiment 1 peak deviation analysis quantitatively described the difference between the interresponse-time distributions of rats trained on variable-interval 300-s and differential-reinforcement-of-low-rate 72-s schedules of reinforcement. In Experiment 2 peak deviation analysis differentiated between the effects of the psychomotor stimulant d-amphetamine, the anxiolytic compound chlordiazepoxide, and the antidepressant desipramine. The results suggest that peak deviation analysis of interresponse-time distributions may provide a useful behavioral assay system for characterizing the effects of drugs.     

The influence of parenting stress and child behavior problems on parental estimates of expressive and receptive language development

This study examined the relative contributions of parental reports of child-related and parent-related stress to their estimates of expressive and receptive language skills on the Minnesota Child Development Inventory in 152 children referred to a communicative disorders clinic. Correlational analysis showed moderately high agreement between parental estimates and objective measures of expressive and receptive language ability. Multiple-regression analyses revealed that independent measures of language acquisition accounted for the greatest amount of variance in parental estimates of expressive and receptive language skills. Stressful child behavior accounted for a small but statistically significant proportion of the variance in estimates of expressive and receptive language skills. Parental stress, in contrast, did not contribute significantly to language estimates. These findings suggest that parents are able to formulate estimates of language development which are relatively independent of personal or child-related stressors.     

The Role of Mothers and Fathers

The development of personality characteristics appears to differ by sex of child and role of parent, with interpersonal concerns tending to characterize mothers and instrumental concerns describing fathers. Using a semi-structured interview protocol and paper-and-pencil questionnaires, we examined the effects of parenting, as reported by middle-class high school senior boys and girls, on the development of two aspects of personality. Ego development and self-esteem both have demonstrated sex differences, with girls displaying more advanced ego development and boys displaying higher self-esteem. We expected that mothers, because of their greater interpersonal orientation, would influence the development of ego development more than would fathers, and that, based on past findings, the opposite-sex parent would exert the primary influence on self-esteem. While ego development was found to relate to more encouraging, warmer mothering in boys, it related weakly to mothering in girls. Boys and girls who perceived their cross-sex parent to be warm and supportive were found to have higher self-esteem.     

Program report: “time-in”: A two-year project for the reduction of severe maladaptive behaviors in a center for persons with developmental disabilities

The results of a two-year project designed to organize a unit for 18 developmentally disabled clients with severe behavior disorders (primarily aggression) were presented. Providing tightly organized structure and focusing on appropriate resident behavior resulted in substantial gains. Noted changes included significant decreases in aggression, total number of target behaviors, required uses of restrictive procedures, and residents' injuries. Decreases were also noted in staff injuries and turnover. Subjectively, the unit became a better place to work and live. Difficulties encountered with developing, maintaining, and generalizing the project were discussed.     

The distribution of infant attention during object examination

The distribution of attention during toy play was studied in 6‐, 9‐ and 12‐month‐old infants. Heart rate and behavior measures of attention were collected as the infants interacted with objects. There was a large deceleration of heart rate at the beginning of behaviorally defined focused attention, but little heart rate change for looks that only had behaviorally defined casual attention. Heart‐rate‐defined sustained attention occurred more frequently at the transition from the first instance of casual attention within a look to focused attention and during the cycling between subsequent epochs of casual and focused attention. These results show that heart rate and behavioral measures of attention are closely related in young infants at the beginning and end of object interaction but are inconsistently related within a single look at an object.