The isolation of a bacterial mutation in a gene, designated groPC, which affects the growth of phages lambda and P2 is described. Lambda replication is severely limited in the strain, and some lambda pi mutations, which map in (or near) the P gene, allow growth. The gro mutation, groPC259, is recessive to wild type and maps between threonine (thr) and diaminopimelate (dapB) on the E. coli chromosome. The possibility that the groPC gene is concerned with host DNA replication is discussed.

With regard to intellectual performance, a large body of research has shown that stigmatized group members may perform more poorly when negative, self-relevant stereotypes become activated prior to a task. However, no research to date has identified the potential ramifications of stereotype activation that happens after-rather than before-a person has finished performing. Six studies examined how postperformance stereotype salience may increase the certainty individuals have in evaluations of their own performance. In the current research, the accessibility of gender or racial stereotypes was manipulated after participants completed either a difficult math test (Studies 1-5) or a test of child-care knowledge (Study 6). Consistent with predictions, stereotype activation was found to increase the certainty that women (Studies 1, 2, 4, and 5), African Americans (Study 3), and men (Study 6) had toward negative evaluations of their own test performance. These effects emerged when performance-related perceptions were stereotype consistent rather than inconsistent (Studies 1-6) and were found to be most pronounced among those who were highly identified with the stereotyped group (Study 5). Furthermore, greater certainty-triggered by negative stereotypes-predicted lowered domain-relevant beliefs (Studies 1, 2, 3, and 6) and differential exposure to domain-relevant stimuli (Studies 4 and 5).

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Past research on the desirability bias and on bracing for bad news has focused on the potential influence of outcome desirability on people's stated expectations. The present studies examined its influence on behavior—that is, what is done in anticipation of, or preparation for, an uncertain outcome. In five studies, the desirability of possible outcomes for an event, which was uncertain and uncontrollable by the participant, was manipulated, and preparation behavior was measured. Study 1 used a hypothetical‐events paradigm. Studies 2 and 3 involved a computer activity in which behavior was tracked on a trial‐by‐trial basis. In Studies 4 and 5, the uncertain event was the ending of a videotaped basketball game. Rather than exhibiting bracing or a reluctance to tempt fate, participants tended to behave in a manner consistent with an optimistic desirability bias. In a subset of studies, predictions and likelihood judgments were also solicited; the differential effects of outcome desirability on these measures are discussed. Copyright © 2015 John Wiley & Sons, Ltd.

The phenomenon of ambiguity aversion suggests that people prefer options that offer precisely rather than imprecisely known chances of success. However, past work on people's responses to ambiguity in health treatment contexts found ambiguity seeking rather than aversion. The present work addressed whether such findings reflected a broad tendency for ambiguity seeking in health treatment contexts or whether specific attributions for ambiguity play a substantial role. In three studies, people choose between two treatment options that involved similar underlying probabilities, except that the probabilities for one option involved ambiguity. The attributions offered for the ambiguity played an important role in the results. For example, when the range of probabilities associated with an ambiguous treatment was attributed to the fact that different studies yield different results, participants tended to show ambiguity aversion or indifference. However, when the range was attributed to something that participants could control (e.g., regular application of a cream) or something about which they were overoptimistic (e.g., their immune system function), participants tended to show ambiguity seeking. Health professionals should be mindful of how people will interpret and use information about ambiguity when choosing among treatments.