Expectations about plant edibility in 6-month-old infants

Abstract

Watching what others put in their mouths is a powerful way to learn what to eat. Yet human diets and eating behaviors are complicated, and not everything that goes into another person's mouth is food: The fusilli is edible, but the fork is not. Therefore, some selectivity is necessary to guide social learning processes about food. Here we examined 6-month-old infants' expectations about what kinds of entities are likely to be edible using a violation-of-expectation setup in which infants viewed an actor eating from two different items. We hypothesized that infants may have selective edibility expectations about plants, and in particular fruits, that stem from humans' long evolutionary history of foraging wild plant foods and specialization in higher caloric density plant parts. In Experiment 1 (N = 40), we found that infants expect plants, relative to feature-matched artifacts, to be edible, replicating a previous finding [Wertz & Wynn, 2014a]. In Experiments 2 (N = 40) and 3 (N = 39), we examined, for the first time, whether selective expectations about plant edibility are tied to particular plant parts. Our results showed that infants do not differentially expect leaves to be edible, but our results for fruits were inconclusive. Taken together, these findings suggest that infants differentially expect plants to be edible and that these expectations appear to be strongest for whole plants.