Exposure to descriptions of traumatic events narrows one's concept of trauma.

The concept of "trauma" was originally used by psychiatrists to describe horrific events such as rape and torture that characteristically provoke extreme emotional distress. Both colloquially and clinically, the concept of psychological trauma has broadened considerably. Although many clinical scientists have expressed concern about the broadening of the concept of trauma, it remains unclear how this concept expansion occurs. We present two experiments in which American adults (N = 276 and N = 267) sequentially classified descriptions of events (e.g., "broke a leg in a bicycle accident") as either "trauma" or "not trauma." In the first experiment, we manipulated the frequency of severe events (i.e., severe events became less and less common). In the second experiment, we manipulated the range of events (i.e., participants viewed only severe or only nonsevere events). Together, the findings suggest that an individual's frame of reference for the severity of events plays a role in narrowing or broadening the concept of trauma. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

White (but Not Black) Americans Continue to See Racism as a Zero-Sum Game; White Conservatives (but Not Moderates or Liberals) See Themselves as Losing.

In a 2011 article in this journal entitled "Whites See Racism as a Zero-Sum Game That They Are Now Losing" (Perspectives on Psychological Science, 6, 215-218), Norton and Sommers assessed Black and White Americans' perceptions of anti-Black and anti-White bias across the previous 6 decades-from the 1950s to the 2000s. They presented two key findings: White (but not Black) respondents perceived decreases in anti-Black bias to be associated with increases in anti-White bias, signaling the perception that racism is a zero-sum game; White respondents rated anti-White bias as more pronounced than anti-Black bias in the 2000s, signaling the perception that they were losing the zero-sum game. We collected new data to examine whether the key findings would be evident nearly a decade later and whether political ideology would moderate perceptions. Liberal, moderate, and conservative White (but not Black) Americans alike believed that racism is a zero-sum game. Liberal White Americans saw racism as a zero-sum game they were winning by a lot, moderate White Americans saw it as a game they were winning by only a little, and conservative White Americans saw it as a game they were losing. This work has clear implications for public policy and behavioral science and lays the groundwork for future research that examines to what extent racial differences in perceptions of racism by political ideology are changing over time.

Range-frequency effects can explain and eliminate prevalence-induced concept change.

Why would concepts seem to grow when their instances become rare? Human observers can respond to decreases in stimulus prevalence by expanding their conceptual boundaries of those stimuli. This prevalence-induced concept change may have serious social consequences, since many real-world detection tasks demand consistent judgments over time. The current work aims to identify the computational process that produces prevalence-induced concept change. I review some plausible models from the cognitive and social sciences that could account for this phenomenon, and then use trial-level computational modeling to see how well each model predicts actual human data, finding that they are best explained as a range-frequency compromise in judgment. Finally, I test an intervention that successfully eliminates prevalence-induced concept change by making stimuli more intense as they become rare.

Tips From the Top: Do the Best Performers Really Give the Best Advice?

Everyone knows that if you want to learn how to do something, you should get advice from people who do it well. But is everyone right? In a series of studies (N = 8,693), adult participants played a game after receiving performance advice from previous participants. Although advice from the best-performing advisors was no more beneficial than advice from other advisors, participants believed that it had been-and they believed this despite the fact that they were told nothing about their advisors' performance. Why? The best performers did not give better advice, but they did give more of it, and participants apparently mistook quantity for quality. These studies suggest that performing and advising may often be unrelated skills and that in at least some domains, people may overvalue advice from top performers.

Feedback moderates the effect of prevalence on perceptual decisions.

How does the prevalence of a target influence how it is perceived and categorized? A substantial body of work, mostly in visual search, shows that a higher proportion of targets are missed when prevalence is low. This classic low prevalence effect (LPE) involves a shift to a more conservative decision criterion that makes it less likely that observers will call an ambiguous item a target. In contrast, Levari et al. (Science, 360[6396], 1465-1467, 2018) recently reported the opposite effect in a simple categorization task. In their hands, at low prevalence, observers adopted a more liberal criterion, making observers more likely to label ambiguous dots on a blue-purple continuum "blue." They called this "prevalence-induced concept change" (PICC). Here, we report that the presence or absence of feedback is critical. With feedback, observers become more conservative at low prevalence, as in the LPE. Without feedback, they become more liberal, identifying a wider range of stimuli as targets, as in Levari's PICC studies. Stimuli from a shape continuum ranging from rounded ("Bouba") to bumpy ("Kiki") shapes produced similar results. Other variables: response type (2AFC vs. go/no-go), color (blue-purple vs. red-green), and stimuli type (solid color vs. texture) did not influence the criterion shifts. Understanding these effects of prevalence and ways they can be controlled illuminates the context-specific nature of perceptual decisions and may be useful in socially important, low prevalence tasks like cancer screening, airport security, and disease diagnosis in pathology.

Prevalence-induced concept change in human judgment.

Why do some social problems seem so intractable? In a series of experiments, we show that people often respond to decreases in the prevalence of a stimulus by expanding their concept of it. When blue dots became rare, participants began to see purple dots as blue; when threatening faces became rare, participants began to see neutral faces as threatening; and when unethical requests became rare, participants began to see innocuous requests as unethical. This "prevalence-induced concept change" occurred even when participants were forewarned about it and even when they were instructed and paid to resist it. Social problems may seem intractable in part because reductions in their prevalence lead people to see more of them.