The problem with attempts to improve the well-being of captive chimpanzees is that even the best efforts at environmental enrichment do not ensure immediate, clear-cut outcomes due to the complex nature of chimpanzee society and cognition Additionally, multiple alternative measures are necessary for outcome evaluation because well-being cannot be measured directly (via self-reports) in chimpanzees In this article, we suggest that the notion of emotion as an intervening variable is useful for integrating complex structures of society and cognition and complex causal relationships among multiple enrichment attempts and multiple consequences. Well-being can be regarded as a homeostatic state under which individual emotional components interact with one another in a complex, wellbalanced manner. The use of emotion as an intervening variable thus contributes to a synthetic view of chimpanzee society, cognition, and well-being.

Key words: animal well-being, chimpanzee, cognition, emotion, environmental enrichment