Animal studies have yielded compelling evidence that early environmental manipulations can be associated with long-term effects that persist into adulthood. For example, maternal licking and grooming in rats is known to have long-term influences on stress response and cognitive performance in their offspring (Champagne et al. 2008, Meaney 2010). Further, a series of studies conducted in macaque monkeys demonstrates that early rearing conditions can result in long-term increased aggression, more reactive stress response, altered neurotransmitter functioning, and structural brain changes (Stevens et al. 2009). These findings parallel research in humans that suggests that early life experiences can have long-term effects on child development (Loman & Gunnar 2010). Elegant work in animal models suggests that epigenetic changes may be involved in these associations (Meaney 2010, Zhang & Meaney 2010).
