CONTRACTUALISM AND ANIMALS

Philosophical Studies -     

AN EXPERIENTIALLY DERIVED BASE-RATE ERROR IN HUMANS

Abstract— Two experiments tested college students in a delayed matching-to-sample procedure designed to explore how multiple competitive sources of control interact in determining choice behavior. The primary sources of potential control were the frequency with which each of two colors was correct (base rates) and the accuracy of a sample in predicting the correct choice (accuracy rate). In one experiment, subjects ignored the base rates, and therefore made nonoptimal choices. These results mimicked the well-known base-rate error found in verbal responses to questions. In a second experiment, manipulations to increase subjects' motivation did not alleviate the error significantly. Together, these results suggest that the base-rate error may represent a broad behavioral pattern not restricted to verbal arenas. The results are compared with previous attempts to reconcile behavioral and cognitive lines of experimentation.     

Spatial compatibility of signal-response position in pointing

Two experiments are reported in which, by means of a pointing task, we studied the stimulus-position effect, i.e. the inverted U-shape form of the reaction-time function in relation to stimulus position in tasks in which stimuli and/or responses are arranged in a horizontal array. The response consisted of aiming the index finger from a central starting point at a target area on a screen. Reaction time was the main dependent variable. The spatial relation between the position of the imperative signal and the position of the response was manipulated by varying the spatial S-R compatibility and physical distance that separated the positions of stimulus and response. The stimulus-position effect was shown to depend on the compatibility of the S-R relation (Exp. 1). In Exp. 2 it was found that the modulation of the stimulus-position effect by spatial compatibility disappeared completely when the distance between the positions of stimulus and response was reduced. None of the experiments revealed that the stimulus position effect depended on signal discriminability, which renders an interpretation of this effect in terms of perceptual processes unlikely. We argue that the attentional model of spatial coding provides the most reasonable explanation of the obtained reaction-time patterns.     

Visual imagery in backward masking

Observers viewed briefly presented target dot patterns, either at low contrast without a mask (no mask, or NM) or at high contrast and followed by a long-lasting patterned mask (backward masking, or BM). Experiment 1 demonstrated independent processing of NM target dots but limited capacity processing of BM target dots. Experiments 2 and 3 showed that visual images may radically change sensitivity (d′) in BM but not in NM. Results suggest that d′ is reduced if the image suppresses dots relevant for the detection task, but that d′ is raised if the image suppresses dots that compete for processing with those the observer must detect.     

A twin study of personality and temperament during middle childhood

In a study of 105 same-sex twin pairs, ages 7 to 10 years, maternal ratings on 23 bipolar scales yielded six factors designated as compliant morality, applied cognitive, sociability, emotionality, tough-mindedness, and activity-distractibility. Analyses by twin pairs (68 identical, 37 fraternal) indicated that correlations for identical pairs were significantly higher than fraternal pairs on all but one factor: tough-mindedness. Profile analyses for the six factors indicated that the profiles of scores across the factors were more concordant for the identical twin pairs. Correlations obtained from the individual scales produced differences between the identical and fraternal twin pairs as well. Overall, the data suggested that several components and the total organization of those components of personality and temperament are genetically influenced.     

Are there constraints on childhood disfluency?

Analysis of the spontaneous speech of eight stuttering and eight normally fluent children reveals that (a) the location of both stuttering and normal disfluent moments is constrained by sentential constituent structure, and (b) stuttering children experience fluency breakdown with a particular type of constituent (verb phrase) not usually disfluently produced by normals. A view of early stuttering as a sentence planning and integration disorder is present.     

Sexual activity and contraceptive use among low-income urban black adolescent females.

A modified form of Nathanson and Becker's (1983) Health Belief Model Questionnaire and other measures designed to assess cognitive processing were administered to low-income black adolescent female clients of an inner-city comprehensive health care clinic. The purpose of the study was to explore determinants of sexual activity and contraceptive use. Subjects were classified as not sexually active (n = 50), sexually active/noncontracepting (n = 20), or sexually active/contracepting (n = 72). Not sexually active subjects tended to be younger, more career motivated, to have a father at home, to be more influenced by family values, and to have more conservative attitudes regarding adolescent sexuality than did sexually active subjects. Sexually active/noncontracepting subjects tended to report fewer benefits and more barriers to the use of contraception. Level of cognitive processing did not differ among the three groups, but was at a lower-than-expected level for age. Finally, inconsistent contraceptive use was common to both sexually active groups.     

Central issue importance as a function of gender and ethnicity

A recent theoretical model of centrality (Bernstein, 1987; Bernstein, Hofmann, Santiago, & Diebolt, 1989) suggests that the importance attached to certain “central issues” may increase the vulnerability of individuals to distress and depression, and may explain the differential rates of depression among gender, racial, and ethnic groups. The present study was designed to examine the importance of central issues as reported by Anglo, Black, and Hispanic men and women (N=169). Multivariate analyses revealed significant gender, ethnicity, and gender X ethnicity effects. Specifically, women considered Intimacy significantly more important than did men, whereas men attached more importance than women to Affiliation. Anglos rated Achievement significantly higher than did Hispanics and Blacks; Hispanics considered Affiliation more important than the other two groups; and Blacks considered Intimacy the least important among the groups. Moreover, Hispanic men attributed significantly greater importance to Change, Adventure, and Control, whereas Hispanic women attached the least significance among all the groups to Control. The results are discussed in terms of cultural influences on sex role orientation and central issues, and the process by which culture and ethnicity may be related to vulnerability to depression and distress.     

Factorial validity and reliability of the Devereux Elementary School Behavior Rating Scale

The factorial validity and internal consistency reliability of the Devereux Elementary School Behavior Rating Scale was examined using a random sample of elementary-school children in grades I through 6. Teacher ratings of subjects' classroom behaviors on the Devereux approximated ratings obtained by the standardization sample. Internal consistency (coefficient alpha) reliability coefficients of the 11 Devereux subscales were found to be quite adequate, ranging from 80 to 93. Intercorrelations among Devereux subscales were moderate to high. A principal factor analysis of the 11 subscales produced two factors with eigenvalues greater than 1.0, which cumulatively accounted for 70.2% of the total variance. When rotated via an orthogonal (Varimax) solution, the two resultant factors appeared to measure emotional adjustment and academic related dimensions of classroom behavior. Given the problem of multicollinearity that was shown to exist among subscales, the authors suggest caution in the interpretation of Devereux subscales as discrete factors.The authors gratefully acknowledge computer support funding provided by the University of Wisconsin, Graduate School Research Committee Grant 135-1537 to the first author.