New Research @ the CEP

Here, you will find recent articles, tips, and a new feature–Forever Fresh

Dropdown menu: Research Topics has pages about the many topics studied at the CEP, from spatial cognition, cooperation, and the evolution of sex to kinship, emotions, and the arts; “Oldies but Goodies” has some of our all-time favorite papers; and the Critical Eye responds to many issues, past and present

Forever Fresh

Newly featured: The most testable concept in biology, Part 1. John Tooby, 1999.

Moral psychology

Moral judgment

The lifeways of our hunter-gatherer ancestors routinely created moral dilemmas—situations in which intuitions about right and wrong collide. Are these important adaptive problems solved by an irrational process—a tug-of-war between emotions and reasoning perhaps? Or has selection produced a cognitive system with a rational design: one that weighs competing moral considerations and identifies which available solution is most right? To find out, see

A moral trade-off system produces intuitive judgments that are rational and coherent and strike a balance between conflicting moral values by Guzmán, Barbato, Sznycer, & Cosmides, Proceedings of the National Academy of Sciences, 2022.

For more: UCSB press releaseWhat is it about? Commentary by Lieberman & Shenouda. Response to Greene, PNAS 2023.

Can evolutionary biology inform moral psychology?

To find out, see The evolution of moral cognition. by Cosmides, Guzmán, & Tooby in The Routledge Handbook of Moral Epistemology, 2019. 

Making welfare tradeoffs—the cognitive foundations of helping and harming others

New! A Bayesian ideal observer model shows that people make rational inferences about how much others value them based on sparse information–and this computation governs anger, even when no costs are imposed. See Rational inferences about social valuation by Quillien, Tooby, & Cosmides, Cognition.

Cognitive foundations for helping and harming others: Making welfare tradeoffs in industrialized and small-scale societies by Delton, Jaeggi, Lim, Sznycer, Gurven, et al., Evolution and Human Behavior, 2023.  See HBES blog

Rational information search in welfare tradeoff cognition by Tadeg Quillien, Cognition, 2023.

Social exchange and reciprocation

How to keep good partners and avoid cheaters

Why punish cheaters?: Those who withdraw cooperation enjoy better reputations than punishers, but both are viewed as difficult to exploit by Arai, Tooby, & Cosmides, Evolution and Human Behavior, 2023. For more, see HBES blog

Motivations to reciprocate cooperation and punish defection are calibrated by estimates of how easily others can switch partners by Arai, Tooby, & Cosmides, PLoS One, 2022.


For a new, evolutionary take on rationality, see Adaptationism: A meta-normative theory of rationality by Cosmides & Tooby in The Handbook of Rationality, 2021.

Natural selection and the nature of communication builds a foundation for thinking about communication at all levels, from genes to cells to organisms to members of a culture. John Tooby & Leda Cosmides (2020) In Handbook of Communication Science and Biology, K. Floyd & R. Weber (eds.). 

For how representations of ancestral situations shape how we see the modern world, see John Tooby on Evolutionary psychology as the crystalizing core of a unified modern social science. Evolutionary Behavioral Sciences, 2020.

For new research on causal cognition and psychological essentialism, see Tadeg Quillien’s website!