de Waal, F. B. M. 1992. A social life for chimpanzees in captivity. In: Chimpanzee Conservation and Public Health: Environments for the Future. Erwin, J. , Landon, J. C. (eds), 83-87. Diagnon/Bioqual, Rockville, MD.

Even the mere 'naming' of study subjects is still occasionally being questioned. ... Yet, experience tells us that we remember names better than numbers [p. 8]. ... Primate intelligence is to a large extent 'social' intelligence. Efforts to provide an interesting and variable life to captive primates should focus, therefore, on the social environment. The physical housing conditions will then automatically be dictated by the requirements of group housing. ... Social companions are the one 'enrichment device' to which habituation never occurs (p. 86). ... We all realize that one is better off with the ups and downs of a social life than without a social life at all. Would it be any different with nonhuman primates? (p. 86)