From infancy through old age, many people's lives are enriched by the love of a pet. In addition, both volunteer and trained service animals are an increasingly common sight as they participate in hospital, school, and nursing home visitation and therapeutic programs. Yet, there has been little scientific research on the role that pets and therapeutic animals play in our health and development. While animal-assisted therapies appear promising, they often lack solid evidence of effectiveness. More research is therefore needed to understand the effects of human-animal interaction (HAI) and to...