What is it about the human species that makes it so different from any other species on the planet? Humans have unmatched technologies, organize with ever more complex forms of institutions and governments, and develop economies that allow the inhabitation of every place on this planet and even beyond. Across disciplines, scientists believe that it is the unusual propensity of humans for cooperation and cultural learning that makes this possible. It is currently thought that these aspects of human psychology arose because evolution shaped the very way human psychology develops. Specifically, it has been proposed that human social skills emerge extremely early in development relative to other apes and that these skills allow human infants to learn from adults in ways that other species cannot. To test the idea that human infants uniquely develop, researchers are carrying out the first large scale longitudinal developmental study designed to compare how the cognition of infant bonobos and chimpanzees develop. Dozens of chimpanzee and bonobo infants living in African sanctuaries are being followed as they grow up over three years so that their cognition can be evaluated and directly compared to that of human infants. In doing so crucial developmental patterns responsible for unique human cognitive abilities are being identified that can help explain the origins of development disorders.
Education programs are developed to assure that African and U.S. students benefit from the knowledge that the results produce and underrepresented populations are participating in the research. The web and other media are used to communicate results to the broader public. Finally, this research is supporting African partners in the critical mission of enforcing conservation laws aimed at reducing the poaching of the last remaining wild apes in their African home.
Humans seem completely different from all other animals. We have ipads, planes, buildings, political parties, legal systems and all manner of institutions. Yet, when neuroscientists have compared the human brain and genome to other great apes such as bonobos and chimpanzees there is surprisingly little difference. The challenge we met in this grant was to understand how humans can be so different in intelligence from other great apes while being so similar in the structure and function of our genes and brains. One powerful technique evolutionary biologists can use to understand the way in which species became different is to study their development. Humans are not born with adult levels of intelligence – these skills develop just as our muscles or teeth grow during life. We predicted that whatever allows for unique human intelligence, it will develop very differently in humans than other apes. This means similar to how an engineer might study how two race cars or computers were built to understand why one is faster than the other, we examined how humans develop problems solving skills to better understand what is responsible for human forms of intelligence. Our major discovery was the possession of early emerging social skills in human infants relative to nonhuman ape infants. While the temperament, motivation and nonsocial problem solving skills of young infant bonobos and chimpanzee are similar to human infants, our infants already outperform other ape infants on a myriad of social problems as early as two years of age. These social skills are the same abilities that allow young human infants to begin communicating and cooperating with other humans in ways that allow them to learn language and acquire culture. It is likely that these early emerging skills provide the cognitive scaffold onto which most future skills are built. By interacting with their social world in a way that other apes do not at such an early age, human infants can learn things from others they otherwise could not learn on their own. Human infants essentially evolved to build on the knowledge of past generations in a way other species simply cannot. We concluded that this set of early emerging social skills must be a crucial part of what makes us human. This discovery suggests future work examining how human brains and genomes allow for this early social development. The current work and the future work it suggests promises to give us a better understanding of developmental disorders in human children and the neurobiological processes that cause developmental delays. In addition, we were only able to show this developmental pattern by following the development of a large group of bonobo and chimpanzee infants over a three year period and then comparing their performance to those of humans. The only place to study such a large population of infant apes is in Africa. All of our research funding went to support the conservation and welfare efforts of the groups caring for the apes we study. We have also shared our findings in a variety of public venues including public TV documentaries, written and radio pieces. We have also written a New York Times bestselling book The Genius of Dogs that includes the findings from this work to help people understand the implications.
