The integration of multidimensional scaling and multivariate analysis with optimal transformations

The recent history of multidimensional data analysis suggests two distinct traditions that have developed along quite different lines. In multidimensional scaling (MDS), the available data typically describe the relationships among a set of objects in terms of similarity/dissimilarity (or (pseudo-)distances). In multivariate analysis (MVA), data usually result from observation on a collection of variables over a common set of objects. This paper starts from a very general multidimensional scaling task, defined on distances between objects derived from one or more sets of multivariate data. Particular special cases of the general problem, following familiar notions from MVA, will be discussed that encompass a variety of analysis techniques, including the possible use of optimal variable transformation. Throughout, it will be noted how certain data analysis approaches are equivalent to familiar MVA solutions when particular problem specifications are combined with particular distance approximations.This research was supported by the Royal Netherlands Academy of Arts and Sciences (KNAW). An earlier version of this paper was written during a stay at McGill University in Montréal; this visit was supported by a travel grant from the Netherlands Organization for Scientific Research (NWO). I am grateful to Jim Ramsay and Willem Heiser for their encouragement and helpful suggestions, and to the Editor and referees for their constructive comments.     

Controlling Stroop effects by manipulating expectations for color words

An important characteristic of automatic processing is its uncontrollability. The Stroop phenomenon is regarded as a prototypical example of this characteristic of automatic processing, hence, the Stroop effect should not change when the percentages of color words versus neutral stimuli are manipulated to induce controlled processing. We found that Stroop interference decreased as the percentage of color words increased. Furthermore, the magnitude of the inhibitory component of the Stroop effect was negatively correlated with the percentage of color words; the facilitatory component was insensitive to the manipulation. These results suggest that the Stroop effect is controllable (see Logan, 1980) and that the locus of control is postlexical. The results also suggest that facilitation and inhibition are produced by different mechanisms and challenge those models of the Stroop phenomenon (e.g., Cohen, Dunbar, & McClelland, 1990; Phaf, Van der Heijden, & Hudson, 1990) that assume that a single processing mechanism causes facilitation and inhibition and that control affects facilitation and inhibition alike (Logan, 1980).     

Verbal hallucinations in normals,I: People who hear ‘voices’

Two studies are reported that describe the phenomena of verbal hallucinations in the general population and test two explanations of those reports. Subjects were 198 male and 387 female college students who completed a verbal hallucination questionnaire plus one or more additional questionnaires. We found that a large minority reported hallucinations and that nearly half reported having them at least once a month. The present data indicated that these reports were not related to four measures of social conformity. Neither were they related to measures of overt, or incipient, symptoms of psychopathology. We have concluded that the majority of these reports are generally veridical accounts of conscious experience in normal individuals.     

Family process and child anxiety and aggression: An observational analysis

Barrett, Rapee, Dadds, and Ryan (1996) described a phenomenon whereby family discussions magnified the style of children's problem solving in a way characteristic of their particular clinical diagnosis. That is, anxious children became more avoidant, aggressive children more aggressive, and nonclinic children more prosocial, after discussing ambiguous hypothetical situations with their parents. This study examined specific sequences of communications exchanged between parents and children hypothesized to underlie this family exacerbation of child cognitive style. Family discussions were videotaped and categorized for groups of anxious, aggressive, and nonclinic children and their parents. Results revealed differences between groups of parents in frequency of agreeing with and listening to their child and the frequency of pointing out positive consequences. Conditional probability analyses showed that parents of anxious children were more likely to reciprocate avoidance, while parents of nonclinic children were more likely to agree with and listen to prosocial plans from their child. Differences in parent behaviors observed during the family discussions were reliably associated with the child's response to the ambiguous situation proposed after the family discussion. Results support a model of developmental anxiety and aggression that emphasizes the interaction of family processes and social-cognitive development in the child.This research was supported by grants from The National Health and Medical Research Council of Australia, The University of Queensland, and The Myer Foundation of Australia.     

SEXUAL ASSAULT HISTORY AND WOMEN'S REPRODUCTIVE AND SEXUAL HEALTH

Associations of sexual assault history with reproductive and sexual symptoms were evaluated in 3,419 women randomly selected from two communities. Sexual assault was associated with excessive menstrual bleeding, genital burning, and painful intercourse (whether or not attributable to disease or injury), medically explained missing two menstrual periods, and medically unexplained dysmenorrhea, menstrual irregularity, and lack of sexual pleasure. Physically violent assaults and those committed by strangers were most strongly related to reproductive symptoms. Multiple assaults, assaults accomplished by persuasion, spouse assault, and completed intercourse were most strongly related to sexual symptoms. Assault was occasionally associated more strongly with reproductive symptoms among women with lower income or less education, possibly because of economic stress or differences in assault circumstances. Associations with unexplained menstrual irregularity were strongest among African American women; ethnic differences in reported circumstances of assault appeared to account for these differences. Assault was associated with sexual indifference only among Latinas.     

Coping Strategies,Substance Use,Sexual Activity,and HIV Sexual Risks in a Sample of Gay Male STD Patients1

The relationships of coping strategies with levels of substance use and sexual activity, and with HIV sexual risks, are examined in a sample of gay male STD clinic patients (n = 416). Previous research has suggested that use of problem-focused coping strategies should be negatively related to levels of substance use, levels of sexual activity, and HIV sexual risks; use of emotion-focused coping strategies should be positively related to these outcomes. It is argued that substance use and sexual activity clearly fit within a coping perspective, but that the HIV sexual risks/coping relationship is less clear. In multivariate analysis, the problem-focused strategy of advice seeking is negatively related to the number of types of drugs used and to the number of sexual partners; the problem-focused strategy of support seeking is negatively related to the number of days using drugs; and the use of emotion-focused strategies is positively related to the number of types of drugs used. Problem-focused coping strategies are less directly related to engaging in HIV sexual risks when measures of substance use and of sexual activity are included in the prediction; emotion-focused coping strategies are more stably related to HIV risk. Indirect effects of coping on HIV risk are also identified through the effects of coping on the number of types of drugs used, number of sex partners, and number of times having sex. It is proposed that the relationships between coping and levels of substance use and sexual activity reflect the use of these activities as ways of relieving strain, but that relationships between coping and HIV sexual risks involve less clearly understood direct and indirect relationships.     

An empirical couple typology based on differentiation

Both spouses of 100 married, heterosexual couples completed the Personal Authority in the Family System Questionnaire (PAFS-Q). A cluster analysis of the couples' scores on the four intimacy and fusion scales of the PAFS-Q produced four clusters that were meaningfully distinct in the patterns of differentiation of the wives and husbands. Couples comprising these clusters are described in terms of intergenerational theories of family interaction.This paper is based on the master's thesis of the first author submitted to the Graduate School of Texas Woman's University. A presentation based on this work was given at the 1988 annual convention of the Southwestern Psychological Association, Tulsa, Oklahoma. The authors thank Glenda Peters and Joe Natale for their contributions to the preparation of this paper. A more extensive report of the methodology and results of this study can be obtained from the second author.