Neural mechanisms of sensitivity to peer information in young adult cannabis users

Though social influence is a critical factor in the initiation and maintenance of marijuana use, the neural correlates of influence in those who use marijuana are unknown. In this study, marijuana-using young adults (MJ; n = 20) and controls (CON; n = 23) performed a decision-making task in which they made a perceptual choice after viewing the choices of unknown peers via photographs, while they underwent functional magnetic resonance imaging scans. The MJ and CON groups did not show differences in the overall number of choices that agreed with versus opposed group influence, but only the MJ group showed reaction time slowing when deciding against group choices. Longer reaction times were associated with greater activation of frontal regions. The MJ goup, compared to CON, showed significantly greater activation in the caudate when presented with peer information. Across groups, caudate activation was associated with self-reported susceptibility to influence. These findings indicate that young adults who use MJ may exhibit increased effort when confronted with opposing peer influence, as well as exhibit greater responsivity of the caudate to social information. These results not only better define the neural basis of social decisions, but also suggest that marijuana use is associated with exaggerated neural activity during decision making that involves social information.     

Does Ontology Rest on a Mistake?: Andre Gallois

I discuss Steve Yablo's defence of Carnap's distinction between internal and external questions. In the first section I set out what I take that distinction, as Carnap draws it, to be, and spell out a central motivation Carnap has for invoking it. In the second section I endorse, and augment, Yablo's response to Quine's arguments against Carnap. In the third section I say why Carnap's application of the distinction between internal and external questions runs into trouble. In the fourth section I spell out what I take to be Yablo's version of Carnap. In the last I say why that version is especially vulnerable to the objection raised in the second.     

Attachment style as a piedictor of sexual attitudes and behavior in late Adolescence

Abstract This research applied attachment theory to the study of sexual attitudes and behaviors in a sample of late adolescents. Four hundred and seventy heterosexual undergraduate students completed questionnaires assessing attachment (discomfort with closeness; anxiety over relationships). relationship history, communication about sex. sexual self-efficacy and locus of control, and attitudes to condoms. Eight weeks later, participants reported on sexual behaviors occurring during the eight-week interval. and perceived risk of these activities. Both discomfort with closeness and anxiety over relationships were associated with external locus of control for sexual outcomes, and with use of drugs before sexual contact. Anxiety over relationships was linked to unsafe sex and to negative attitudes to condoms, but discomfort with closeness was associated with a more cautious approach to sexual risk-taking. Some results were qualified by gender differences. and by differences between the full sample and those who were sexually active. The findings arc discussed in terms of attachment style and its links with communication and affect regulation. SUMMARY AND CONCLUSIONS This study indicates that attachment dimensions are reliably related to many aspects of sexual attitudes and behaviors among late adolescents. Insecure attachment was linked to increased drug use before sexual contact. Anxiety over relationships was also linked to less safe sexual practice, but discomfort with closeness was associated with a tendency for males to be cautious about sexual risk-taking. The results support the utility of the attachment perspective on adolescent sexuality, but also highlight the complex relations between attachment dimensions and sexual outcomes. Future research would benefit from more detailed investigations of the attitudes, emotions, and cognitions which may mediate the link between attachment style and sexual behavior. For example, those who are highly anxious about their relationships may engage in more risky sexual practices because they fear that non-compliance with partners' wishes will jeopardize their relationship; the tendency to engage in drug use before sexual cpntact may reflect their attempts to boost self-confidence or to manage negative mood states. Research into these issues has the potential to explain how attachment insecurity is played out in patterns of sexual activity.     

Safe and Unsafe Sexual Intentions and Behavior: The Effects of Norms and Attitudes1

A study of 85 heterosexual men, 85 heterosexual women, and 82 homosexual men was undertaken to examine the variables that influence intentions to engage in different sexual practices and actual sexual behavior. On the basis of Fishbein and Ajzen's (1975) theory of reasoned action, it was predicted that the strength of intentions would be related to whether behavior was in accord with intentions. Consistent with expectations, the strength of intention to engage in six different sexual practices (e. g., vaginal intercourse, anal intercourse, oral sex) and the three strategies that modify the risk of HIV transmission (sex with an exclusive partner, sex wearing a condom, and looking for a new partner) predicted actual behavior. Second, it was proposed that attitudes toward one's sexual practices and norms would be related to intentions to engage in safe sex. To reflect differential levels in the safety of behavioral intentions, five safety intention groups were formed: (a) nonpenetrative sex, (b) penetrative sex in an exclusive relationship with a condom, (c) penetrative sex in an exclusive relationship without a condom, (d) penetrative sex in a nonexclusive relationship with a condom, and (e) penetrative sex in a nonexclusive relationship without a condom. Norms, rather than attitudes, distinguished the five safety intention groups. the groups intending to engage in safe sex (nonpenetrative sex or penetrative sex with a condom) perceived lower levels of social approval for their sexual practices than the noncondom groups. Additional analyses showed that past behavior had a stabilizing effect on the intention-behavior relationship, but only for the nonpenetrative and noncondom safety intention groups.     

Book Reviews

The Economics of Science: Methodology and Epistemology as if Economics Really Mattered. James R. Wible, 1998. London and New York, Routledge. xviii + 266 pp., US$75.00, £45.00. ISBN 0–415–17257–8

The Dawning of Gauge Theory. Lochlainn O'Raifeartaigh, 1997. Princeton, NJ, Princeton University Press. ix + 249 pp., $US 69.50 (hardback), $US 29.95 (paperback). ISBN 0–691–02978–4 (hardback), 0–691–02977–6 (paperback)

Mathematics as a Science of Patterns. Michael D. Resnik, 1997. Oxford, Clarendon Press. ISBN 0–19–823608–5

Proof Theory and Automated Deduction. Jean Goubault‐Larrecq & Ian Mackie, 1997. Dordrecht, Kluwer. xv+ 425 pp., $US 155, £96. ISBN 0–7923–4593–2 (hardback)     

Sex and least preferred co-worker score effects in leadership behavior

This study investigated the subordinate liking and the leadership style of male and female managers in a simulated business activity. Sixty-seven female and 290 male undergraduate and graduate business students participated in this study. Female managers, on average, were not less well liked, nor were they more accommodative than male managers. Among managers classified as distinctly accommodative, females were not better liked than males; among managers classified as distinctly directive, females were significantly better liked than males. Under pressure to act in a directive manner, males tended to make use of their secondary leadership style as defined by F. E. Fiedler (1972), while females did not.