Humans are remarkably similar to other apes. Like us, chimpanzees and orangutans are extremely clever, use tools and exhibit rudimentary understanding of causality and what others intend. However, other apes are not nearly as good at understanding the intentions of others nor nearly so eager to accommodate or help them. By contrast, right from an early age, humans are eager to help and share. It was this combination of understanding what others intend along with impulses to help and please them that enabled our ancestors to coordinate behavior in pursuit of common goalsï¿½with spectacular consequences later on. So how and why did such other-regarding capacities emerge in creatures as self-serving as nonhuman apes are? And why did they emerge in the line leading to the genus Homo, but not in other apes? In her lecture, Dr. Sarah Hrdy explains why she became convinced that the psychological and emotional underpinnings for these ï¿½other-regardingï¿½ impulses emerged very early in hominin evolution, as byproducts of shared parental and alloparental care and provisioning of young. According to widely accepted chronology, large-brained, anatomically modern humans evolved by 200,000 years ago, while behaviorally modern humans, capable of symbolic thought and language, evolved more recently still, in the past 150,000 or so years. But Hrdy hypothesizes that emotionally modern humans, interested in the mental and subjective states of others emerged far earlier, perhaps by the beginning of the Pleistocene 1.8 million years ago.