Common knowledge—what everyone knows that everyone knows, ad infinitum—is theoretically required for coordination. But a finite mind cannot represent infinitely embedded propositions, and even a few are cognitively taxing. We propose that people perceive common knowledge by combining a capacity-limited ability for recursive mentalizing with an intuitive sense of public salience: When an event is jointly and openly witnessed, they infer that recursively embedded beliefs are licensed. We probed participants’ attributions of embedded beliefs to characters in fictitious vignettes. Study 1 presented narratives in which the information available to characters was either asymmetrical, reciprocal, or public. Participants indicated their confidence in the characters’ beliefs with 0, 2, 4, 6, and 18 embeddings (the latter judged indirectly). Ratings showed i) a decline with number of embeddings, reflecting cognitive load, ii) modest overattribution of embedded beliefs in the nonpublic conditions, iii) far higher attribution of embedded beliefs in the public conditions, and iv) high indirect judgments that arbitrarily deep beliefs were justified. Study 2 replicated these findings with animated videos in which the characters’ information was private, reciprocal, doubly reciprocal, or public. Together, the studies indicate that people attribute common knowledge to observers of a publicly salient event, while being susceptible to capacity-driven recursion collapse and heuristic extrapolation (false embedded beliefs). This can explain how humans achieve coordination from sparse cues, yet sometimes miscoordinate when publicness is absent or embedding grows complex.

Why do people speak vaguely when they propose illicit deals? We examine the strategic use of vague speech. Participants play an economic game in which a schemer and accomplice can coordinate to take money from a mark. When a cop was watching, the schemer was more likely to send a vague message (“Some things are better left unsaid”) to the accomplice, which usually recruited the accomplice to collude. In Experiment 2, the schemer could write their own message. When the cop was watching, they wrote messages that were more vague, which again recruited the accomplice effectively.

This special issue of Developmental Review is in honor of Judith Rich Harris and the important contributions she made to the study of child development. Though she lacked traditional credentials and a university position, her work forced professional scholars to reconsider a foundational tenet in psychology. Contrary to both evidence and intuition, Harris argued that parents had no lasting influence on the personalities, preferences, and temperaments of their children. Her ideas were met with incredulity, and it would take time before reflexive doubt gave way to more careful consideration. In the decades following the publication of her most well-known book, The Nurture Assumption, , her influence has spread well beyond the boundaries of her own field, developmental psychology. Contributors to this volume include criminologists, social psychologists, and behavior geneticists alike. The special issue represents an exciting opportunity to reflect on a remarkable psychologist and the legacy that endures from her unlikely scholarly career.

Science is among humanity’s greatest achievements, yet scientific censorship is rarely studied empirically. We explore the social, psychological, and institutional causes and consequences of scientific censorship (defined as actions aimed at obstructing particular scientific ideas from reaching an audience for reasons other than low scientific quality). Popular narratives suggest that scientific censorship is driven by authoritarian officials with dark motives, such as dogmatism and intolerance. Our analysis suggests that scientific censorship is often driven by scientists, who are primarily motivated by self-protection, benevolence toward peer scholars, and prosocial concerns for the well-being of human social groups. This perspective helps explain both recent findings on scientific censorship and recent changes to scientific institutions, such as the use of harm-based criteria to evaluate research. We discuss unknowns surrounding the consequences of censorship and provide recommendations for improving transparency and accountability in scientific decision-making to enable the exploration of these unknowns. The benefits of censorship may sometimes outweigh costs. However, until costs and benefits are examined empirically, scholars on opposing sides of ongoing debates are left to quarrel based on competing values, assumptions, and intuitions.

Harvard Data Science Review's Founding Editor-in-Chief, Xiao-Li Meng, and Media Feature Editor, Liberty Vittert, interviewed Dr. Steven Pinker, the Johnstone Family Professor in the Department of Psychology at Harvard University and expert on the human mind, about how artificial intelligence is viewed within his fields of study. Dr. Pinker has researched and published several articles and books on language, cognition, and social relations. In this conversation, these two data scientists and an experimental cognitive psychologist theorize about the future societal roles of AI platforms like ChatGPT and discuss whether technology has the ability to be rational and intelligent, as well as how those terms might vary in definition between different fields and between the human brain and AI.