Parent-Offspring and Sibling Adoption Analyses of Parental Ratings of Temperament in Infancy and Childhood

A first step toward understanding the etiology of personality is to investigate the relative impact of genetic and environmental factors using twin and adoption designs. Twin studies of infants and young children indicate substantial genetic influence for parental ratings of temperament in the preschool years. Adoption studies, however, have not previously been reported during the early years of life. We present parent-offspring comparisons for temperament (emotionality, activity, sociability, and impulsivity) for adopted and nonadopted children yearly from 1 to 7 years of age and their biological, adoptive, and nonadoptive parents. Also presented are correlations for adoptive and nonadoptive siblings when each child was 1, 2, 3, and 4 years of age. In contrast with twin results, little evidence is found for genetic influence. The average correlation between biological parents and their adopted-away children for data averaged over the 7 years is only .03. Similarly, the average parent-offspring correlation in nonadoptive families (.08) is no greater than in adoptive families (.12). Results for nonadoptive and adoptive siblings also indicate little genetic influence. The difference between the twin and adoption results may be due to environmental effects or to nonadditive genetic variance.     

The development of children's action memory: When do actions speak louder than words?

Summary Although acting consistently has been found to improve memory, the reasons for this are unclear. In this investigation, we tested whether acting improves recall by integrating separate elements within an action into an organized whole and whether this process may be strategic. First graders, fourth graders, and college-aged adults listened to, acted out, or watched the performance of action-object phrases and then verbally reported or enacted the phrases. Phrases composed of transitive verbs were expected to be integrated more by action than phrases composed of intransitive verbs, and consequently recalled better, especially by the younger children. Recall increased between first and fourth grades, suggesting that some aspects of action memory may be strategic; however, there was no evidence that acting improves recall by means of integration. The pattern of results suggested that the nature of an action's outcome may contribute to the enactment effect.     

Emotional Empathy in a Courtroom Simulation: A Person-Situation Interaction1

A pair of experiments were conducted using a simulated courtroom trial of a criminal case. In Experiment I subject-jurors were asked by defense counsel either to imagine themselves as the defendant (empathy-inducing appeal) or to pay close attention to evidence (nonempathy appeal). Later the judge delivered only general instructions or, in addition, charged jurors to give consideration only to the facts presented. When there was no Fact-focused judge's charge, juror-subjects who heard the empathy-inducing appeal rated the defendant's actions as more lawful and attributed less of the cause for the incident to his personality than did their counterparts in the nonempathy condition. Experiment II included individual differences in the tendency to empathize as an additional mediating variable. The original pattern of effects found for the manipulated variables in Experiment I appeared again, but were overshadowed by the stronger effects of the individual difference variable and of subject sex. Subject-jurors who scored high on the empathy individual difference measure rated the defendant less guilty, assigned less cause to him, and showed corresponding mood shifts when they heard the empathy-inducing appeal. In addition, male subjects empathized more strongly with the male defendant and viewed him more favorably.     

Transection of direct anterior thalamic afferents from the hippocampus: effects on activity and active avoidance in rats

This investigation demonstrates the importance of the direct hippocampo-anterior thalamic component of the postcommissural fornix in the control of general locomotion and active avoidance. Transection of anterior thalamic afferents from the hippocampal formation (subicular cortex), at the point where they exit from the fornix posterior to the septum, is sufficient to enhance bidirectional active avoidance acquisition and increase general activity. This transection may also interrupt fibers to or from other thalamic nuclei and the anterior septum. However, destruction of connections of the anterior septum with the hippocampus, habenula, and thalamus by transection in the coronal plane anterior to the descending fornix columns, without damage to the subiculothalamic fibers, increases general activity levels without damage to the subiculothalamic fibers, increases general activity levels without affecting active avoidance behavior. The activity increase in this case resembles that seen after septal lesions rather than that seen after hippocampal lesions. Thus, destruction of a single fornix component contributing afferents to the anterior thalamic nuclei reproduces at least part of the hippocampal syndrome. This suggests that these fibers contribute significantly to the control of these behaviors and may mediate active avoidance changes resulting from hippocampal and fornix damage.     

The effects of delayed auditory feedback on the overt behaviors of stutterers

This study investigated the differential effect of delayed auditory feedback (DAF) upon general (e.g., repetitions) and specific (e.g., repetitions of initial, medial, and final syllables) overt types of dysfluent behaviors. Ten moderate to severe stutterers performed an oral reading task under both NDAF and DAF (200 msec). DAF resulted in a significant increase in the total number of dysfluencies but had a differential effect upon certain general and specific behaviors. Blocks decreased significantly, prolongations increased significantly, and repetitions and interjections did not change significantly in frequency of occurence. To a limited extent, DAF had a differential effect on specific behaviors. All specific prolongation behaviors increased significantly while only one specific block behavior (ddelays in starting words) decreased. The authors discuss these results in terms of the vocal changes that occurred under DAF and speculate as to their importance in establishing fluency. DAF is viewed as promoting prolongations and prolongations are viewed as inhibiting excessive stoppages of the breathstream, thus promoting fluency (e.g., delays in starting words).