This paper reports selected results of a quantitative study of the affective behaviour of the Efe, exchange-dependent hunter-gatherers of the Ituri forest in northeastern Zaire. Measures of the amount and kind of affective display were based on systematic, direct observation of the routine behavior of three Efe bands in residential settings (camps), using a new technique to characterize affect-laden behavior according to nonlinguistic information conveyed in the voice. Resulting data provide a direct measure of the affective milieu of a foraging people, providing an objective indicator of the subjective impact of social and ecological conditions, which are thought to affect quality of life. In this paper, measures of “camp mood” are used to explore the psychosocial impact of a 3-month period of acute food shortage that occurred in the Ituri Project study area in 1983. Contrary to expectation, rates of behaviors conveying pleasure did not exhibit significant change, whereas a 44% increase in expressions of displeasure and a 17% drop in use of complaint tones were observed during the period of hunger. This and other findings support the view that systematic, direct observation in natural habitats can increase our understanding, both of the functions of affective behavior, and of the affective dimension of quality of life.