Selection for general intelligence in carnivores by novel environments

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Understanding how and why intelligence has evolved in humans and other animals is a grand challenge in biology. Animal intelligence is composed largely of specialized abilities that respond to specific pressures in the environment. However, many recent discoveries suggest that non-specific, general intelligence, similar to IQ in humans, also evolves. Most hypotheses about the evolution of intelligence suggest that general intelligence evolves as a side effect of selection for more specialized cognitive abilities. In contrast, the Cognitive Buffer hypothesis suggests that general intelligence is directly favored by natural selection when animals are coping with novel environments. Urban environments are evolutionarily novel to most animals today, and present them with many new cognitive challenges. This work tests predictions of the Cognitive Buffer Hypothesis by presenting wild spotted hyenas living in rural, urban, and transitional habitats in Africa with a battery of simple tests, much like IQ testing in humans. Performance on each specific task in the test battery will be compared among hyenas in the three habitat types, but a general intelligence measure will also be calculated from the individual test scores, and related to the strength of natural selection acting in each habitat. This work will permit determination of whether or not the strength of selection on general intelligence varies among ancestral, historically urban and rapidly-urbanizing environments. Broader impacts include international training of students, working closely with film crews to create television documentaries, and production of a children's book on hyena research.The evolution of intelligence represents one of the greatest challenges in biology. Animal intelligence is composed largely of specialized abilities evolving in response to specific selection pressures, but recent work suggests that domain-general processes also evolve. The Cognitive Buffer hypothesis posits that general intelligence is favored directly by natural selection to help animals cope with novel environments. Urban environments are evolutionarily novel to most animals, presenting them with many new cognitive challenges. Here, predictions of the Cognitive Buffer hypothesis will be tested in the context of urbanization by presenting a test battery, focusing on seven elementary cognitive abilities, to 175 wild spotted hyenas occupying rural, urban, and transitional habitats in Africa. Performance on each specific task will be compared among the 3 habitat types, but a psychometric factor-analytical approach will also permit statistical derivation of a general intelligence measure, g, for individuals within each habitat type, and elucidation of the structure of hyena intelligence. Because data are available in each habitat on survival and reproduction, the strength of selection on g can be compared among the three different environments. Comparing selection gradients on g among habitat types permits assessment of the strength of directional selection acting on general intelligence in each environment. This work permits determination of whether the strength of selection on g varies among ancestral, historically urban and rapidly-urbanizing environments. Broader impacts include international training of students, working closely with film crews to create television documentaries, and production of a children's book on hyena research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.