Parametrically Dissociating Speech and Nonspeech Perception in the Brain Using fMRI

Candidate brain regions constituting a neural network for preattentive phonetic perception were identified with fMRI and multivariate multiple regression of imaging data. Stimuli contrasted along speech/nonspeech, acoustic, or phonetic complexity (three levels each) and natural/synthetic dimensions. Seven distributed brain regions' activity correlated with speech and speech complexity dimensions, including five left-sided foci [posterior superior temporal gyrus (STG), angular gyrus, ventral occipitotemporal cortex, inferior/posterior supramarginal gyrus, and middle frontal gyrus (MFG)] and two right-sided foci (posterior STG and anterior insula). Only the left MFG discriminated natural and synthetic speech. The data also supported a parallel rather than serial model of auditory speech and nonspeech perception.     

Integration versus decomposition in the retention of complex ideas

Four accounts of the processes underlying the retention of connected sentences expressing complex ideas were critically evaluated and experimentally compared. The constructive theory and the imagery theory emphasized the integration of the information expressed by different stimulus items; the tally theory and the fragmentation theory emphasized the decomposition of the information contained within individual stimulus items. In Experiment 1, concrete ideas did not show better integration than abstract ideas, and imagery mnemonic instructions failed to enhance the integration of concrete ideas; these findings were inconsistent with the imagery theory. Moreover, the detailed pattern of performance was inconsistent with specific predictions of the tally theory. In Experiments 2 and 3, a componential analysis was found to provide an accurate representation of performance in cued recall. However, patterns of recall were found that could not have resulted from a fragmentation process, but only from the integration of information from different stimulus items. Once again, concrete ideas did not show significantly better integration than abstract ideas. These findings support a constructive approach, according to which the synthesis of information into holistic representations involves abstract semantic processes that do not depend upon the use of mental imagery.     

Explaining the Social and Psychological Impacts of a Nuclear Power Plant Accident1

This research investigates the antecedents of psychosocial impacts of the TMI nuclear power plant accident. A model of factors that are hypothesized to affect impact levels is developed and configured to approximate a hypothetical causal sequence. Using data from the Nuclear Regulatory Commission telephone survey, the technique of path analysis is used to test relationships in the model. The results show that the antecedents explain 12% of the variance in individual stress, 45% of the variance in family disruption, and 16% of the variance in perceived community change. The analysis shows that the TMI specific attitudes and sensitivity to radiation risks are strong antecedents of impacts. Although general attitudes toward nuclear power have minor indirect effects, it appears that situational experiences with the accident are the major contributors toward explaining impact levels.     

Hypothermia-induced anterograde amnesia: is memory loss attributable to impaired acquisition?

The present investigation examined whether the poor test performance observed in studies of anterograde amnesia reflects a memory deficit or is a by-product of weaker initial learning resulting from impaired sensory, motivational, or associative processes. Two experiments were performed which utilized latent extinction (Experiment 1) and delay of punishment (Experiment 2) manipulations in order to assess the nature of original learning in rats trained under either hypothermic (29 degrees C) or normothermic conditions. Results from both experiments provided evidence that hypothermia treatment administered prior to training had relatively little influence on the animal's ability to acquire a passive avoidance response. Therefore, the rapid forgetting observed in hypothermia-induced anterograde amnesia is most likely due to memory deficits rather than an artifact of poorer acquisition.     

Self-concept and attitude to school as predictors of academic achievement by West Indian adolescents

The Coopersmith Self-esteem Inventory and the School Sentiment Index were administered to 215 West Indian middle-class 14-yr.-olds (95 boys and 120 girls) to assess their validity as predictors of academic achievement. Step-wise multiple regression analysis identified School-Academic, a self-concept measure, as the strongest predictor of academic achievement.     

Sex-role orientation of Caribbean adolescents

A total of 140 Caribbean middle-class 17-yr.-olds (68 boys and 72 girls) completed the Bem Sex-role Inventory. Analyses indicated strong stereotypical behavior in the direction of each group's respective sex-type.     

Effects of home nest odors on black-white preference in the developing rat: implications for developmental learning research

Developing animals 17 and 30 days of age were tested for black-white preference in the presence of either clean shavings or soiled bedding material from the home cage. Home nest shavings markedly reduced dark preference in 17-day-old rats but had no effect on dark preference in 30-day-old rats. Because many developmental studies have used two-compartment, black and white chambers to study the effects of familiar home nest shavings on learning and memory, it may be that differential preference for black influenced the results obtained. The apparent alleviation of learning and memory deficits produced by the presence of home nest shavings may have been the result of changes in black-white preference rather than differences in learning and memory per se. Similar influences may underlie the effects of home nest stimuli on other learning tasks such as spatial alternation.