Inhibition of the LH Surge by Restraint Stress in Cyclic Rats: Studies on the Role of GABAA and GABAB Receptors

There is evidence that stress can alter the activity in the brain of gamma-aminobutyricacid (GABA), a neurotransmitter that has been implicated in the regulation of LH secretion. In the present study the role of GABA in the restraint stress-induced inhibition of the LH surge was investigated in the intact cyclic rat. Intracerebroventricular (icv) administration of the GABAA receptor agonist muscimol (0.1, 0.5 or 1 μg) 5 min before the presumed onset of the pro-oestrous LH surge (at 0900 h) caused a dose dependent suppression of the surge. A single dose of the GABAB receptor agonist baclofen (1 μg; icv) injected at 0855 h postponed the onset of the LH surge, and repeated injections at 0855 and 1130 h suppressed the surge. These data indicate that GABA-ergic activity in the brain can inhibit the LH surge in the cyclic rat via GABAA and GABAB receptors. Pro-oestrous rats were subjected to 5 hrs of restraint starting at 0855 h. Pretreatment with the GABAA receptor antagonist bicuculine (1 μg; icv) at 0840, 0940 and 1040 h or pretreatment with the GABAB receptor antagonist phaclofen (10 μg; icv) at 0840 h were ineffective in preventing the restraint-induced inhibition of the LH surge. The results suggest that GABAA and GABAB receptors are not involved in the inhibitory effect of restraint stress on the LH surge.     

Perspective and prejudice: antecedents and mediating mechanisms

The present work investigated mechanisms by which Whites' prejudice toward Blacks can be reduced (Study 1) and explored how creating a common ingroup identity can reduce prejudice by promoting these processes (Study 2). In Study 1, White participants who viewed a videotape depicting examples of racial discrimination and who imagined the victim's feelings showed greater decreases in prejudice toward Blacks than did those in the objective and no instruction conditions. Among the potential mediating affective and cognitive variables examined, reductions in prejudice were mediated primarily by feelings associated with perceived injustice. In Study 2, an intervention designed to increase perceptions of a common group identity before viewing the videotape, reading that a terrorist threat was directed at all Americans versus directed just at White Americans, also reduced prejudice toward Blacks through increases in feelings of injustice.     

Ambivalence and Response Amplification Toward Native Peoples1

This study determined whether ambivalence toward Native peoples would result in amplified, or polarized, responses to members of the group, as assessed in terms of both general attitudes and social policy endorsements. In addition, it examined whether priming would mediate these effects, based on the notion that ambivalent attitudes contain both positive and negative dimensions that may be activated at different times. Induction of different mood states was used as an indirect priming manipulation. One hundred thirty-eight Canadian participants completed measures of ambivalence toward Native peoples and Canadians. One week later, these participants underwent a positive, neutral, or negative mood induction procedure. They then indicated their attitudes toward Native peoples and Canadians, and responded to social policy questions involving both groups. Participants who were highly ambivalent or not ambivalent toward Native peoples were retained for analysis; participants generally displayed low ambivalence toward Canadians. It was predicted and the results confirmed that only participants who were ambivalent toward Native peoples would display a relative response amplification effect: a greater difference between positive and negative mood states in their responses to Native peoples than in their responses to Canadians.     

Lay perceptions of ethnic prejudice: causes,solutions, and individual differences

We assessed lay perceptions of the causes of and solutions to ethnic prejudice, and determined whether individual differences related to intergroup relations (social dominance orientation, right‐wing authoritarianism) and to cognitive style (personal need for structure, need for cognition) were predictive of these perceptions. Results revealed clear and coherent lay beliefs about the causes of and solutions to ethnic prejudice, and significant relations between perceived causes and solutions. Systematic relations between the intergroup‐relevant individual differences and these perceptions also emerged, in ways that may serve to justify and legitimize ethnic bias. Implications for the justification and maintenance of ethnic bias and for intervention programmes are discussed. Copyright © 2005 John Wiley & Sons, Ltd.     

Physical Attractiveness,Dangerousness, and the Canadian Criminal Code1

The Canadian Criminal Code contains provisions for labelling certain convicted criminal offenders as Dangerous Offenders. Sentences of indefinite duration are usually imposed on these offenders in place of the fixed sentences that would normally be imposed. The present study examined one potential source of bias in the use of the Dangerous Offender provisions, the physical attractiveness of an offender. Two hundred and eighty-four adults were given information about a hypothetical offender, including a facial photograph and a conviction record. They responded to questions about the dangerousness of the offender, including questions drawn from the Dangerous Offender criteria. Subjects perceived physically unattractive sexual offenders as significantly more likely to fulfill the Dangerous Offender criteria than average-looking and attractive sexual offenders. In particular, unattractive sexual offenders were seen as significantly less likely to restrain their behavior in the future. In light of the fact that there is currently no evidence that physical attractiveness is a valid predictor of sexual offender recidivism, this finding provides grounds to question whether the Dangerous Offender provisions of the Canadian Criminal Code, as they now stand, can be administered impartially.     

Assessing individual differences in the degree to which people are committed to following their beliefs

The authors developed a new dispositional measure of Commitment to Beliefs (CTB)—the degree to which people feel it is important to follow their value-expressive beliefs—across three phases of research. In Phases 1 and 2 (Studies 1-4), the CTB scale demonstrated strong internal consistency, and convergent and discriminant validity. Phase 3 demonstrated the scale’s predictive validity: high-CTB individuals were more likely to report engaging in activities during the past month and year that followed directly from their beliefs (Study 5), act on their beliefs when given the opportunity (Study 6), and show more polarized attitudes toward ideologically-relevant groups (Study 7). These findings illustrate the utility of a dispositional approach for examining the extent to which people follow their beliefs.     

The need for affect: individual differences in the motivation to approach or avoid emotions

The present research developed and tested a new individual-difference measure of the need for affect, which is the motivation to approach or avoid emotion-inducing situations. The first phase of the research developed the need for affect scale. The second phase revealed that the need for affect is related to a number of individual differences in cognitive processes (e.g., need for cognition, need for closure), emotional processes (e.g., affect intensity, repression-sensitization), behavioral inhibition and activation (e.g., sensation seeking), and aspects of personality (Big Five dimensions) in the expected directions, while not being redundant with them. The third phase of the research indicated that, compared to people low in the need for affect, people high in the need for affect are more likely to (a) possess extreme attitudes across a variety of issues, (b) choose to view emotional movies, and (c) become involved in an emotion-inducing event (the death of Princess Diana). Overall, the results indicate that the need for affect is an important construct in understanding emotion-related processes.     

Mental Representation of Familiar Others: The Impact of Occupation,Sex, and Race

The current study used a double primed semantic decision task to investigate the role of social group information in mental representations of familiar others. Extrapolating from social role theory, we predicted that social role information would facilitate responding to familiar targets regardless of the specific task at hand. The names of celebrities were used as stimuli, as people know them because of their social role (i.e., their occupation). Primes and targets were matched (or mismatched) on all combinations of sex, race, and occupation. Participants were randomly assigned to task condition: indicating whether the prime and target were (a) of the same sex or not, (b) of the same race or not, or (c) of the same occupation or not. Results indicated that participants responded faster to celebrity prime-target pairs that were matched on occupation regardless of task condition. In addition, participants responded faster to celebrity prime-target pairs that were matched on sex—but only when sex was relevant to the task. Similar findings were not found for race. The implications of these findings for understanding mental representations of familiar others and for person perception are discussed.