Fruits are a common source of nutrients, containing potassium, vitamin C, and more; however, a new study in Nature Ecology & Evolution suggests that fruit may also be the reason why our primate ancestors developed larger brains over time.
According to the study, the social brain hypothesis has been supported by studies suggesting that group size and social behaviors are linked to brain size. To test this theory, Alex DeCasien, a Ph.D. candidate in biological anthropology at New York University, expanded the sample size of primates in the study to see what factors were most associated with larger brain sizes.
After comparing the dietary habits and social behaviors of over 140 species of monkeys, apes, lorises, and lemurs, the study found that a diet filled primarily with fruit, as opposed to a leaf-centric diet, was the most likely factor in predicting larger brains.
DeCasien attributes fruit-filled diets to larger brain size with the idea that eating fruit might be more “cognitively challenging” than eating leaves. DeCasien says that acquiring fruit may have required more navigational skills and the ability to work around difficulties in comparison to eating leaves, which can be more accessible, Science reported.
Although nutrient-rich diets can nourish the brain, others in the field question whether the dietary habit is enough to have caused its evolution. Richard Wrangham, a biological anthropologist at Harvard University, told Science that rather than being the driving force behind the evolution of brain size, a fruit-filled diet may have been one of several factors that enabled it.