Animal-assisted therapy (AAT) is a type of therapy that involves animals as a form of treatment. The goal of AAT is to improve a patient's social, emotional, or cognitive functioning. Advocates state that animals can be useful for educational and motivational effectiveness for participants.[1] A therapist who brings along a pet may be viewed as being less threatening, increasing the rapport between patient and therapist. Animals used in therapy include domesticated pets, farm animals and marine mammals (such as dolphins). The research literature states concerns about the poor quality of medical evidence underpinning AAT. Wilson's (1984) biophilia hypothesis is based on the premise that our attachment to and interest in animals stems from the strong possibility that human survival was partly dependent on signals from animals in the environment indicating safety or threat. The biophilia hypothesis suggests that now, if we see animals at rest or in a peaceful state, this may signal to us safety, security and feelings of well-being which in turn may trigger a state where personal change and healing are possible.[4] A contrast is sometimes made with Animal assisted activity (AAA). AAA is more casual and unstructured than AAT, involving perhaps more than one patient and with the primary focus on the presence of the animal itself.