Knowledge that Transforms

Beginning in infancy, children expect individuals in a group to care for and be loyal to in-group members. One prominent cue that children use to infer that individuals belong to the same group is similarity. Does any salient similarity among individuals elicit an expectation of in-group preference, or does contextual information modulate these expectations? In Experiments 1 and 2, 12-month-old infants expected in-group preference between two individuals who wore the same novel outfit, but they dismissed this similarity if one of the outfits was used to fulfill an instrumental purpose. In Experiment 3, 26-month-old toddlers expected in-group preference between two individuals who uttered the same novel labels, but they dismissed this similarity if the labels were used to convey incidental as opposed to categorical information about the individuals. Together, the results of these experiments ( N = 96) provide converging evidence that from early in life, children possess a context-sensitive mechanism for determining whether similarities mark groups.

Inaccurate stereotypes—perceived differences among groups that do not actually differ—are prevalent and consequential. Past research explains stereotypes as emerging from a range of factors, including motivational biases, cognitive limitations, and information deficits. Considering the minimal forces required to produce inaccurate assumptions about group differences, we found that locally adaptive exploration is sufficient: An initial arbitrary interaction, if rewarding enough, may discourage people from investigating alternatives that would be equal or better. Historical accidents can snowball into globally inaccurate generalizations, and inaccurate stereotypes can emerge in the absence of real group differences. Using multiarmed-bandit models, we found that the mere act of choosing among groups with the goal of maximizing the long-term benefit of interactions is enough to produce inaccurate assessments of different groups. This phenomenon was reproduced in two large online experiments with English-speaking adults ( N = 2,404), which demonstrated a minimal process that suffices to produce biased impressions.

Pretend play is a ubiquitous learning tool in early childhood, enabling children to explore possibilities outside of their current reality. Here, we demonstrate how pretend play can be leveraged to empower girls in scientific domains. American children ages 4 to 7 years ( N = 240) played a challenging science activity in one of three conditions. Children in the exposure condition heard about a successful gender-matched scientist, children in the roleplay condition pretended to be that scientist, and children in the baseline condition did not receive information about the scientist. Girls in the roleplay condition, but not in the exposure condition, persisted longer in the science activity than girls in the baseline condition. Pretending to be the scientist equated girls’ persistence to that of boys. These findings suggest that pretend play of role models motivates young girls in science and may help reduce gender gaps from their roots.

When a log burns, it transforms from a block of wood into a pile of ash. Such state changes are among the most dramatic ways objects change, going beyond mere changes of position or orientation. How does the mind represent changes of state? A foundational result in visual cognition is that memory extrapolates the positions of moving objects—a distortion called representational momentum. Here, five experiments ( N = 400 adults) exploited this phenomenon to investigate mental representations in state space. Participants who viewed objects undergoing state changes (e.g., ice melting, logs burning, or grapes shriveling) remembered them as more changed (e.g., more melted, burned, or shriveled) than they actually were. This pattern extended to several types of state changes, went beyond their low-level properties, and even adhered to their natural trajectories in state space. Thus, mental representations of objects actively incorporate how they change—not only in their relation to their environment, but also in their essential qualities.

Performing acts of kindness increases well-being, yet people can be reluctant to ask for help that would enable others’ kindness. We suggest that people may be overly reluctant because of miscalibrated expectations about others’ prosocial motivation, underestimating how positively others will feel when asked for help. A pretest identified that interest in asking for help was correlated with expectations of how helpers would think and feel, but a series of scenarios, recalled experiences, and live interactions among adult participants in the United States (total N = 2,118) indicated that those needing help consistently underestimated others’ willingness to help, underestimated how positively helpers would feel, and overestimated how inconvenienced helpers would feel. These miscalibrated expectations stemmed from underestimating helpers’ prosocial motivation while overestimating compliance motivation. This research highlights a limitation of construing help-seeking through a lens of compliance by scholars and laypeople alike. Undervaluing prosociality could create a misplaced barrier to asking for help when needed.

In the United States, police are becoming increasingly militarized. Whereas the racialized nature of police militarization has been documented, the relationship between racial prejudice and police militarization is less understood. We assessed the link between racial prejudice against Black and Native Americans and police militarization at individual and regional levels. Study 1 ( N = 765) recruited a nationally representative sample of White Americans and found a positive association between racial prejudice and support for police militarization. Study 2 ( N = 3,129,343) sourced regional aggregates of prejudice among White Americans from Project Implicit and policing data from the Defense Logistics Agency and found that police departments in states higher in prejudice acquired greater amounts of militarized equipment. Together, these studies demonstrate that, in terms of attitudes and policies, racial prejudice predicts police militarization.

= 10,556 adult participants, including more than 20,000 observed choices across 25 issues) documented how people perceive and respond to relative progress out in the world, revealing a robust "negative-lumping" effect. As problematic entities worked to better their ways, participants shifted to dismiss them if they fell short of categorical reform-despite distinctions in improvement. This increased dismissal of relative gains as "all the same" was driven by the belief that falling short signals an eschewal of doing the bare minimum and lacking serious intent to change, making these gains seem less deserving of recognition. Critically, participants then "checked out": They underrewarded and underinvested in efforts toward "merely" incremental improvement. Finally, in all experiments, participants lumped together absolute failures but not absolute successes, highlighting a unique blindness to gradations of badness. When attempts to eradicate a problem fail, people might dismiss smaller but critical steps that were and can still be made.

Although White Americans increasingly express egalitarian views, how they express egalitarianism may reveal inegalitarian tendencies and sow mistrust with Black Americans. In the present experiments, Black perceivers inferred likability (Experiments 1-2), allyship (Experiment 1a), and trustworthiness (Experiments 1b-2), and accurately inferred underlying racial attitudes and motivations from White writers’ declarations that they are nonprejudiced and egalitarian (Experiments 1 and 2). White writers believed that their egalitarianism seemed more inoffensive than was perceived by Black Americans (Experiment 1a). Linguistic analysis revealed that, when inferring racial attitudes and motivations, Black perceivers accurately attended to language emphasizing humanization, support for equal opportunity, personal responsibility, and the idea that equality already exists (Experiment 1b). We found causal evidence that these linguistic cues informed Black Americans’ perceptions of White egalitarians (Experiment 2). Suggesting societal costs of these perceptions, White egalitarians’ underlying racial beliefs negatively predicted Black participants’ actual trust and cooperation in an economic game (Experiment 3). Our experiments ( N = 1,335 adults) showed that White Americans’ insistence that they are egalitarian itself perpetuates mistrust with Black Americans.

Can people accurately perceive who is authentic? Laypeople believe they can tell who is authentic, and they report that authenticity is an important attribute in others (Studies 1a and 1b; N = 369). However, when we directly tested the accuracy of perceived authenticity, we found no significant correlation between self- and other-rated authenticity in two cohorts of adult students in randomly assigned teams (Studies 2 and 3; 4,040 self-other observations). In addition, we found that perceived authenticity was biased in two ways: (a) Other-rated authenticity showed a positivity bias compared with self-ratings, and (b) other-rated authenticity was biased by the rater’s own authenticity. In Study 3, we also investigated authenticity meta-perceptions; although people expect their authenticity to be accurately perceived by others, their meta-perceptions did not correlate with other-rated authenticity. That is, beliefs about the visibility of one’s authenticity are similarly not accurate. Overall, we found no evidence that people can accurately identify who is authentic.

Past research has established that observing the outcomes of forgone alternatives is an important driver of regret. In this research, we predicted and empirically corroborated a seemingly opposite result: Participants in our studies were more likely to experience regret when they did not observe a forgone outcome than when it was revealed. Our prediction drew on two theoretical observations. First, feelings of regret frequently stem from comparing a chosen option with one’s belief about what the forgone alternative would have been. Second, when there are many alternatives to choose from under uncertainty, the perceived attractiveness of the almost-chosen alternative tends to exceed its reality. In four preregistered studies ( Ns = 800, 599, 150, and 197 adults), we found that participants predictably overestimated the forgone path, and this overestimation caused undue regret. We discuss the psychological implications of this hidden source of regret and reconcile the ostensible contradiction with past research.