The seeds of social learning
Plants have been central to human life across evolutionary time as sources of food and raw materials for artifact construction. However, plants also manufacture potentially dangerous chemical and physical defenses to protect themselves from herbivores. These circumstances create a fundamental problem: How does each individual human learn which plants in her local environment are food and which plants are fatal? Because there are no morphological features that reliably predict human-relevant edibility or toxicity, employing a trial-and-error strategy to learn about the specific plants in an environment would be extremely costly. Instead, I argue that human cognitive architecture contains social learning mechanisms specialized for acquiring information about plants over the course of ontogeny. I will present evidence from a series of studies with human infants exploring this proposal. The results indicate that infants possess a combination of behavioral avoidance and social information seeking strategies that allow them to safely learn about plants from more-knowledgeable others. I will close by discussing the broader implications of these findings for the evolution of learning mechanisms and the generation of human culture.