Cue interaction in human contingency judgment

Most studies of human contingency judgment have been based on the assumption that frequency information about one predictor is assessed in isolation of information about other predictors. Recent evidence, however, suggests that the judged predictive strength of one cue is influenced by the predictive strengths of other copresent cues. Two experiments demonstrate that stimuli with the same outcome contingencies may nonetheless have different predictive strengths as the result of cue interaction. The first experiment, in which a within-subject design was used, provides a demonstration of blocking. A stimulus presented in compound with a strong predictor was rated as less predictive than another stimulus that was presented in compound with a nonpredictive cue. In the second experiment, cue interactions in conditioned inhibition were examined. A stimulus gained negative predictive strength as the result of compound presentations with a positive predictor when the outcome was not presented. This negative predictor was compared with an otherwise analogous stimulus that was not presented in compound with a positive predictor. These results support the use of animal-conditioning models as accounts of human contingency learning.     

Evidence for cortical dysfunction in spasmodic dysphonia: regional cerebral blood flow and quantitative electrophysiology

Cortical function was evaluated in 26 subjects with spasmodic dysphonia. Quantitative topographic electrophysiologic mapping (QTE) was employed to provide quantitative analyses of EEG spectra and auditory and visual long-latency evoked potentials. Single-photon emission computed tomography (SPECT) of the cerebral transit of Xenon-133 was used to evaluate regional cerebral blood flow. Left hemispheric abnormalities in cortical function were found by both techniques in 10 subjects and by at least one technique in 18 subjects. Right hemispheric abnormalities were observed by both techniques in 8 subjects and by at least one technique in 18 subjects. Most patients with cortical dysfunction in one hemisphere had cortical dysfunction in the other, while only 4 subjects had unilateral lesions as found by one of the two techniques. Eight subjects were normal by all measurements. Underlying structural abnormalities were detected by magnetic resonance imaging in 5/24 subjects. However, functional abnormalities (SPECT or QTE) were not observed at sites of structural abnormalities. SPECT and QTE were significantly related in identification of left hemispheric dysfunction (p = .037) with a trend in the right hemisphere (p = .070), and a significant congruence of SPECT and QTE findings occurred in the left anterior cortical quadrant (p = .011). These findings indicate that dysfunction of cortical perfusion and/or cortical electrophysiology is associated with spasmodic dysphonia in the majority of subjects studied.     

Anti-litter procedures in an urban high-density area

In urban high-density areas, litter has become an increasingly obvious and pervasive problem. In the present study, repeated measures of the amount of litter on randomly selected yards in an urban low-income housing project were used to evaluate the effectiveness of a series of anti-litter procedures directed at the children residing in the project. Paying children for volume of trash collected resulted in only a small decrease in the number of litter pieces present. Paying them for cleaning assigned yards markedly decreased the level of litter in all sampled yards. Thus, children can be employed to maintain a clean neighborhood in spite of the rapid accumulation of new litter in urban yards.     

The lady spaceman: Children's perceptions of sex-stereotyped occupations

In a study of perceptions of sex-sterotyping in occupations, children from first, fourth, and sixth grades in single-sex schools and a coeducational school were asked to name male and female occupants of traditionally male and traditionally female roles. Use of linguistic markers (e.g., lady doctor) or stereotypically inappropriate responses (e.g., naming a female doctor nurse, while correctly naming the male occupant of this role doctor) was associated with labeling female occupants of traditionally male roles and male occupants of traditionally female roles. The results from this study indicate that language subtly reflects children's perceptions of sex roles.This study was supported by a grant from the Melbourne State College Standing Committee on Research and Development.     

Children's judgment and recall of causal connectives: A developmental study of “because,” “so,” and “and”

The present study examined the acceptability judgments and recall performance of children aged 6,9, and 11 years with sentences expressing psychological cause-effect relations. Thirty-two sentences containing because medially, because initially, so, and and were generated from four clause pairs. Both probable and improbable event orders were used. The results indicated that children preferred because to so or and for statements of psychological causality. However, on both tasks, first and third graders frequently failed to attend to the temporal ordering specified by each sentence construction. The younger children also tended to judge all sentences acceptable, suggesting that they were concerned only with the probable association of event pairs, and not with the usual order of the events. Order of mention strategies did not occur in any group, suggesting that they arise only when children cannot make interpretations based on probable order of events. The data also indicated that the recall task is an unreliable index of rules for comprehension and production.This article is based on research conducted by the first author as partial fulfillment of the Ph.D. requirements for the Department of Educational Policy Studies, University of Wisconsin.     

Cerebral asymmetry for speech in neonates: A behavioral measure

This paper reports a finding of hemispheric brain asymmetry for speech in short-gestation infants (mean gestational AGE = 36 weeks). Using a new measure—degree of reduction in limb tremors following exposure to speech stimuli compared to two control groups, one hearing orchestral music, the other no patterned stimuli—we found that speech disproportionately affected right limb movements. It is not clear whether the effect is due to asymmetries in cortical or subcortical processing. This provides evidence against the notion that brain specialization for language functions necessarily appears over time; rather, specialization for some functions (e.g., speech reception) must be present at birth.