If you find relationships challenging to cultivate and maintain, then you are in good company. In his new book, evolutionary biologist Robin Dunbar argues that our ability to manage such complex social connections—love lives, work colleagues, childhood buddies and friendly acquaintances—is what drove humans to develop such large brains in the first place.

Read the rest of the review of How Many Friends Does One Person Need? Dunbar’s Number and Other Evolutionary Quirks, by Robin Dunbar here.