Intergroup discrimination in the minimal group paradigm: categorization, reciprocation, or fear?

H. Tajfel's (1970) minimal group paradigm (MGP) research suggests that social categorization is a sufficient antecedent of ingroup-favoring discrimination. Two experiments examined whether discrimination in the MGP arises from categorization or processes of outcome dependence, that is, ingroup reciprocity and outgroup fear. Experiment 1 unconfounded categorization from outcome dependence. Categorized men discriminated only when dependent on others. Categorized women discriminated regardless of the structure of dependence. Experiment 2 examined dependence on the ingroup versus the outgroup as the locus of male-initiated discrimination. Consistently with an ingroup reciprocity effect, men discriminated when dependent on ingroup, but not outgroup, members. Sex differences are discussed in regard to women's heightened ingroup dependence produced by biological or environmental constraints.

In search of self-definition: motivational primacy of the individual self, motivational primacy of the collective self, or contextual primacy?

Four investigations examined the dynamics between the individual self (self-representation independent of group membership) and the collective self (self-representation derived from group membership). Relative to participants whose collective self was threatened, participants whose individual self was threatened (a) considered the threat more severe, (b) experienced a more negative mood, (c) reported more anger, and (d) derogated to a greater extent the source of threat. In addition, a self-description task indicated that participants generate more aspects of their individual than collective self. These effects occurred even when confounding variables (i.e., accessibility of the selves, group identification, individualism and collectivism, importance of threat domain) were controlled. The individual self is motivationally primary.

Memory for in-group and out-group information in a minimal group context: the self as an informational base.

The authors argue that persons derive in-group expectancies from self-knowledge. This implies that perceivers process information about novel in-groups on the basis of the self-congruency of this information and not simply its valence. In Experiment 1, participants recalled more negative self-discrepant behaviors about an in-group than about an out-group. Experiment 2 replicated this effect under low cognitive load but not under high load. Experiment 3 replicated the effect using an idiographic procedure. These findings suggest that perceivers engage in elaborative inconsistency processing when they encounter negative self-discrepant information about an in-group but not when they encounter negative self-congruent information. Participants were also more likely to attribute self-congruent information to the in-group than to the out-group, regardless of information valence. Implications for models of social memory and self-categorization theory are discussed.

Interindividual-intergroup discontinuity reduction through the anticipation of future interaction.

Consistent with the role of a long-term perspective in reducing the tendency of intergroup relations to be more competitive than interindividual relations in the context of noncorrespondent outcomes, an experiment demonstrated that anticipated future interaction reduced intergroup but not interindividual competitiveness. Further results indicated that the effect was present only for groups composed of members high in abstractness (Openness-Intellect on the Big 5 Inventory and Intuition on the Myers-Briggs Type Inventory) who trusted their opponents.

Long-term outcome maximization and the reduction of interindividual-intergroup discontinuity.

Two experiments demonstrated that different procedures can be used to reduce the tendency for intergroup relations to be more competitive than interindividual relations. Experiment 1 revealed that this tendency was reduced when individual or group participants interacted with individual or group confederates who followed a tit-for-tat strategy as opposed to a Pavlov strategy or a standard control condition that did not involve confederates. Experiment 2 revealed that the tendency for groups to be more competitive than individuals was less pronounced with successive responding than with simultaneous responding. Further results indicated that the higher the total session score on the Consideration of Future Consequences Scale, the less the competition between groups. The results from both experiments were interpreted as indicating that intergroup competitiveness can be reduced by inducing a concern with long-term outcomes.

Accumulation of daunomycin and fluorescent dyes by drug-transporting Malpighian tubule cells of the tobacco hornworn, Manduca sexta.

Insect Malpighian tubules actively transport a variety of xenobiotics, and it has been proposed that P-glycoprotein (P-gp), or the multidrug transporter, is involved. To test this idea, we observed the interaction of known P-gp substrates with isolated, living Malpighian tubules from tobacco hornworm (Manduca sexta) larvae. Specifically, the fluorescent drugs daunomycin, rhodamine 123, acridine orange and Hoechst 33342 were applied to the basal side of tubules (proximal portion) in a well of fluid on a coverslip; the subsequent distribution of the drugs was monitored by laser scanning confocal microscopy. Contrary to expectation, none of the drugs appeared in the lumen even after 1-2 h of incubation, although the cells of the tubule were intensely stained within 1 min. For daunomycin, neither verapamil, a P-gp inhibitor, nor nicotine, an alkaloid which appears to be transported by a P-gp-like mechanism in this species, had any effect on the pattern of staining. In sharp contrast to the fast and intense staining of Malpighian tubules, portions of muscle, nerve cord and body fat showed only light staining with daunomycin, and only after prolonged periods. The results suggest that for some drugs, Malpighian tubules act as xenobiotic scavengers, and that this property is unrelated to P-gp-mediated transport.

Transepithelial transport of nicotine and vinblastine in isolated malpighian tubules of the tobacco hornworm (Manduca sexta) suggests a P-glycoprotein-like mechanism.

We have examined the accumulative transport properties of the Malpighian (excretory) tubules of the tobacco hornworm Manduca sexta to test the hypothesis that a P-glycoprotein-like multidrug transporter is active and is responsible for the excretion of dietary nicotine in this tissue. Isolated tubules were cannulated and exposed to radiolabelled forms of either nicotine (5 min exposure) or the P-glycoprotein substrate vinblastine (60 min exposure) in the bathing (basal surface) fluid. The luminal (apical) contents were then flushed, and lumen-to-bath ratios were measured. Although these ratios provide conservative estimates of the physiological ability of Malpighian tubules to move compounds from blood to lumen, tubules concentrated nicotine 10-fold from an initial bath concentration of 0.5 mmol l-1 and vinblastine threefold (from an initial concentration of 1 micromol l-1). Vectorial transport of vinblastine and nicotine was eliminated by 25 micromol l-1 verapamil (a P-glycoprotein inhibitor) and was not dependent on the presence of a transepithelial electrical potential. Nicotine transport was inhibited by atropine (3 mmol l-1), while nicotine (> or = 50 micromol l-1) significantly reduced vinblastine transport. Verapamil was effective at reducing vinblastine transport when applied to the basal side alone, but not when applied to the apical side alone. Taken together, these results are consistent with the idea that the active excretion of nicotine and other alkaloids by the tobacco hornworm is mediated by a P-glycoprotein-like mechanism.

Childhood injuries and the importance of documentation in the emergency department.

The purpose of this study is 1) to evaluate the extent to which documentation of the medical record is completed for dependent children who present for evaluation of an acute injury, and 2) to examine the factors that favorably or adversely influence completion of the medical record. The emergency department (ED) ledgers of 669 children less than nine years of age were reviewed, including 172 (25.7%) who presented for evaluation of an acute injury. Each of the latter charts was examined for basic demographic data, as well as information about injury type and mechanism, ED provider, and involvement of social services personnel. The ledgers were further examined to determine completeness of chart documentation in several relevant areas, including the circumstances and characteristics of the acute injury, pertinent past medical history, and course of management and referral while in the ED. Each of 15 individual documentation variables was assigned a score of either zero (incompletely/not addressed or documented) or one (completely addressed or documented). The 15 individual scores were equally weighted and summed, resulting in a total documentation score ranging from zero (failure to address or document any of the 15 variables) to 15 (all variables completely addressed/documented). The mechanisms of injury included falls from height (48.3%), direct blunt impact other than falls (26.7%), penetrating injury (6.4%), burn (5.2%), and ingestion (8.1%). Seventeen patients (9.9%) were admitted for primarily medical, and one (0.6%) for primarily social, indications; one patient died as a result of his injuries.(ABSTRACT TRUNCATED AT 250 WORDS)