Knowledge that Transforms

Resource constraints in neural information processing imply that numerical discriminability optimally adapts to the frequency of numerical magnitudes in a decision maker’s environment. Here, we tested the economic consequences of efficient numerical range adaptation in representative samples of the United Kingdom and Japan ( N = 2,309) and in a replication in Austria and Hungary ( N = 607). We exploited natural variation in currency units and combined it with an orthogonal variation in experimental currency units to detect the effect of habitual versus nonhabitual numerical ranges on the incidence of errors in decisions under risk. The results highlight the direct economic importance of numerical adaptation, thus calling into question standard assumptions that choice quantities are perceived without noise.

The study aimed to investigate the within-person relationship between religious-service attendance and mental health using data from the British Household Panel Survey ( N = 29,298), a longitudinal survey of adult British households between 1991 and 2009. The outcome variables were mental health (as measured with the General Health Questionnaire) and life satisfaction. Using random-intercept cross-lagged panel models over 10 waves of data spanning over 18 years, the associations between religious-service attendance and mental health at the within-person level were mostly nonsignificant. The few significant findings indicated that an increase in religious-service attendance is associated subsequently with either higher or lower levels of mental health, suggesting both detrimental and beneficial effects. A series of robustness analyses (including the use of marginal structural models) mainly supported these findings. The results suggest that there is a need to question the assumption that religious-service attendance provides mental health benefits.

Most people believe in human-caused climate change, yet this public consensus can be collectively underestimated ( pluralistic ignorance ). Across two studies using primary data ( n = 3,653 adult participants; 11 countries) and secondary data ( n s = 60,230 and 22,496 adult participants; 55 countries), we tested (a) the generalizability of pluralistic ignorance about climate-change beliefs, (b) the effects of a public-consensus intervention on climate action, and (c) the possibility that cultural tightness-looseness might serve as a country-level predictor of pluralistic ignorance. In Study 1, people across 11 countries underestimated the prevalence of proclimate views by at least 7.5% in Indonesia (90% credible interval, or CrI = [5.0, 10.1]), and up to 20.8% in Brazil (90% CrI = [18.2, 23.4]. Providing information about the actual public consensus on climate change was largely ineffective, except for a slight increase in willingness to express one’s proclimate opinion, δ = 0.05 (90% CrI = [−0.02, 0.11]). In Study 2, pluralistic ignorance about willingness to contribute financially to fight climate change was slightly more pronounced in looser than tighter cultures, highlighting the particular need for pluralistic-ignorance research in these countries.

Intelligence is known to predict survival, but it remains unclear whether cognitive abilities differ in their relationship to survival in old age. We analyzed longitudinal data of 516 healthy adults (age: M = 84.92 years, SD = 8.66 years at Wave 1) from the Berlin Aging Study (Germany) on nine tasks of perceptual speed, episodic memory, verbal fluency, and verbal knowledge, and a general composite intelligence score. There were eight waves, with up to 18 years of follow-up; all participants were deceased by the time of analysis. We used a joint multivariate longitudinal survival model to estimate the unique contribution of each cognitive ability in terms of true (i.e., error-free) current value and current rate of change when predicting survival. Additional survival covariates included age at first occasion, sex, sociobiographical status, and suspected dementia. Only the two verbal-fluency measures were uniquely predictive of mortality risk. Thus, verbal fluency showed more salient associations with mortality risk than did measures of perceptual speed, episodic memory, and verbal knowledge.

Assortative mating—the tendency to choose partners similar to oneself—is a ubiquitous phenomenon in mate choice. Despite numerous proposed explanations, a parsimonious mechanism has been overlooked: When individuals choose mates on the basis of heritable traits and preferences, offspring inherit a trait and the corresponding preference from each parent, creating genetic correlations that link having a trait to preferring that same trait. We evaluated this mechanism with an agent-based model simulating 100 generations in which agents, with traits and preferences each uniquely determined by 40 loci, chose reproductive partners based on preferences. Genetic correlations formed between preferences and preferred traits, as well as between partner traits (i.e., assortative mating), demonstrating that heritable variation in preferences and preferred traits is sufficient to drive assortative mating. We presented a toy model here, so we cannot speak to the robustness of such genetic correlations or to the relative explanatory power of this mechanism over others.

Prosocial interventions grounded in social interactions have shown limited effectiveness in alleviating depressive symptoms, possibly because of the discomfort and unease that depressed individuals experience during such interactions. We developed and examined an innovative prosocial intervention—an online micro-charitable giving intervention, in which individuals voluntarily donated at least one Chinese cent (¥0.01, or about $0.0014) daily. We conducted three preregistered, 2-month randomized controlled trials with depressed individuals (Sample 1: N = 125, Sample 2: N = 296, Sample 3: N = 462). Results showed that, compared with the waitlist group, the intervention group exhibited significantly greater improvements in both depressive symptoms (Cohen’s d s = −0.19 to −0.46) and emotional positivity (Cohen’s d s = 0.22 to 0.49), and that emotional positivity mediated the intervention’s effect on the reduction of depressive symptoms. Exploratory analysis found a slightly larger intervention effect for generous donors than for minimal donors. This low-cost, easily accessible prosocial intervention holds potential for the prevention of depression. Statement of Relevance Can donating one cent (specifically one Chinese cent, or about $0.0014) alleviate depressive symptoms? We have developed a practical and effective intervention—donating at least one cent daily on an online charity platform—and have discovered that this intervention effectively mitigates depressive symptoms in depressed individuals. Despite the nominal purchasing power of one cent in contemporary society, this act of giving has been shown to significantly enhance mental health. Our findings could be relevant to everyone in society; charitable donations promote societal harmony and, in addition, offer a cost-effective way to alleviate depressive symptoms. As the intervention instruction asserts, “Charity encompasses love, regardless of its size, as even one cent holds value.”