Reasoning about the evolution of our species' capacity for cumulative cultural learning has led culture gene coevolutionary (CGC) theorists to predict that humans should possess several learning biases which robustly enhance the fitness of cultural learners. Meanwhile, developmental psychologists have begun using experimental procedures to probe the learning biases that young children actually possess - a methodology ripe for testing CGC. Here we report the first direct tests in children of CGC's prediction of prestige bias, a tendency to learn from individuals to whom others have preferentially attended, learned or deferred. Our first study showed that the odds of 3- and 4-year-old children learning from an adult model to whom bystanders had previously preferentially attended for 10 seconds (the prestigious model) were over twice those of their learning from a model whom bystanders ignored. Moreover, this effect appears domain-sensitive: in Study 2 when bystanders preferentially observed a prestigious model using artifacts, she was learned from more often on subsequent artifact-use tasks (odds almost five times greater) but not on food-preference tasks, while the reverse was true of a model who received preferential bystander attention while expressing food preferences. (C) 2012 Elsevier Inc. All rights reserved.

The use of socially learned information (culture) is central to human adaptations. We investigate the hypothesis that the process of cultural evolution has played an active, leading role in the evolution of genes. Culture normally evolves more rapidly than genes, creating novel environments that expose genes to new selective pressures. Many human genes that have been shown to be under recent or current selection are changing as a result of new environments created by cultural innovations. Some changed in response to the development of agricultural subsistence systems in the Early and Middle Holocene. Alleles coding for adaptations to diets rich in plant starch (e.g., amylase copy number) and to epidemic diseases evolved as human populations expanded (e.g., sickle cell and deficiency alleles that provide protection against malaria). Large-scale scans using patterns of linkage disequilibrium to detect recent selection suggest that many more genes evolved in response to agriculture. Genetic change in response to the novel social environment of contemporary modern societies is also likely to be occurring. The functional effects of most of the alleles under selection during the last 10,000 years are currently unknown. Also unknown is the role of paleoenvironmental change in regulating the tempo of hominin evolution. Although the full extent of culture-driven gene-culture coevolution is thus far unknown for the deeper history of the human lineage, theory and some evidence suggest that such effects were profound. Genomic methods promise to have a major impact on our understanding of gene-culture coevolution over the span of hominin evolutionary history.

Why Humans Cooperate takes a unique look at the evolution of human cooperation and tries to answer the question: why are people willing to help others at a cost to themselves? The book brings together evolutionary theories, economic experiments, and an anthropological case study that runs throughout the book to explain and illustrate human cooperation.

Using an evolutionary framework, Natalie and Joseph Henrich have expanded upon several diverse theories for explaining cooperative or ‘helpful’ behavior, and integrated them into a unified theory. Established concepts such as kin selection and reciprocity have been linked with theories on social learning and our evolved psychologies to explain the universality of human cooperation—as well as the distinctive ways in which cooperative behavior expresses itself in different cultures.

The theories developed in the book are brought to life by examining the Chaldeans of metropolitan Detroit. By exploring Chaldean cooperation, theoretical concepts are shown to translate into social behavior, and universal psychologies for cooperation lead to culturally-specific norms, beliefs, and practices. The book also introduces a series of economic experiments that help us understand why, when, and to what extent people are willing to help others. These experiments also highlight the variation in behaviors across cultural groups, even when all the groups rely on the same cognitive machinery and evolved psychologies. The merging of theory, experiments, and the Chaldean case study allows for an in-depth exploration of the origins and manifestations of cooperation.

Synthesizing existing work from diverse disciplines, this paper introduces a culture-gene coevolutionary approach to human behavior and psychology, and applies it to the evolution of cooperation. After a general discussion of cooperation in humans, this paper summarizes Dual Inheritance Theory and shows how cultural transmission can be brought under the Darwinian umbrella in order to analyze how culture and genes coevolve and jointly influence human behavior and psychology. We then present a generally applicable mathematical characterization of the problem of cooperation. From a Dual Inheritance perspective, we review and discuss work on kinship, reciprocity, reputation, social norms, and ethnicity, and their application to solving the problem of cooperation. (c) 2006 Published by Elsevier B.V.