Inbreeding and cognitive impairment in animals

The physiological costs of inbreeding in wild animals are well-documented, but the potential cognitive costs of inbreeding have received far less attention. A growing body of evidence indicates that inbreeding is associated with impaired learning ability and aberrant innate behaviors in model systems, as well as intellectual disability and lower general intelligence in humans. As highlighted in this review, however, far less is known about inbreeding-linked cognitive impairments for wild populations and the potential behavioral and fitness implications of these impairments. Here, we review evidence indicating that, through its negative effects on song and other courtship behaviors, as well as its association with deficits in mating behavior and parental care, inbreeding is likely to have negative consequences for reproductive success in wild animals. The impairment of specific cognitive abilities, such as learning, innovation, and decision-making, may be particularly detrimental for inbred animals in changing environments, where individuals must adjust their behavior appropriately to deal with novel threats and resources. Cognitive abilities like learning and memory guide behavior and are important determinants of fitness. A growing body of evidence, however, suggests that inbreeding may impair these abilities. Here, we review evidence for inbreeding-linked cognitive deficits in human and non-human animals and their implications for behavior and fitness. Understanding inbreeding-linked cognitive impairment is timely because of the elevated likelihood of inbreeding in changing environments-the very environments in which cognitive flexibility is critical for population persistence.