Line and others 1991; Novak and Suomi 1988; Novak and others 1993; O'Neill and Price 1991; Suomi and Novak 1991).
Nevertheless, it is possible to identify the important elements that should be considered in designing a program to promote the psychological well-being of captive nonhuman primates. The maxims presented by Yerkes (1925) many years ago concerning the husbandry and well-being of apes still serve as useful guidelines as we move beyond taking care of only the physical needs of nonhuman primates to try to provide for their psychological needs. Yerkes's views on social housing, the importance of work and play, the need for congenial and capable caregivers—all presaged contemporary views about primate psychological needs. We believe that a well-designed plan to provide for psychological well-being should promote balanced or positive temperament as defined in the previous chapter. To achieve these goals, the plan should include
Social interactions are considered to be one of the most important factors influencing the psychological well-being of most nonhuman primates. A social environment enables nonhuman primates to perform many species-appropriate activities, including grooming, play, sleeping huddles, and sexual behavior. Moreover, partners contribute to meeting other psychological needs by providing variation (e.g., social interactions that are not completely predictable), challenge (e.g., competition for access to objects), and opportunity for control (e.g., play bouts) (Mineka and Kihlstrom 1978; Mineka and others 1986). Most primates normally live in social groups, and they should be socially housed if they are to express many aspects of their normal behaviors. However, the introduction of strange cagemates should be done gradually under conditions that minimize the likelihood of injurious aggression. For example, compatibility might be assessed by observing animals while they occupy adjacent cages, before allowing them to interact (Reinhardt 1989a).
Knowing that most primates benefit from social interactions, it should be obvious that they can be harmed by a lack of social interaction. Harlow and Suomi (1971), Harlow and others (1971), Novak (1979), and numerous others have elicited profound behavioral problems by rearing infant and young macaques