Institute for the Study of Child Development University of Medicine and Dentistry of New Jersey Robert Wood Johnson Medical School Preschool children, 2 to 5 years of age, and adults posed the six facial expressions of happiness, surprise, anger, fear, sadness, and disgust before a videotape camera. Their poses were scored subse- quently using the MAX system. The number of poses that included all components of the target expression (complete expressions) as well as the frequency of those that included only some of the components of the target expressions (partial expressions) were analyzed. Results indicated that 2- year-olds as a group failed to pose any face. Three-year-olds were a transitional group, posing happi- ness and surprise expressions but none of the remaining faces to any degree. Four- and 5-year-olds were similar to one another and differed from adults only on surprise and anger expressions. Adults were able to pose both these expressions. No group, including adults, posed fear and disgust well. Posing of happiness showed no change after 3 years of age. Consistent differences between partial and complete poses were observed particularly for the negative expressions of sadness, fear, and disgust. Implications of these results for socialization theories of emotion are discussed. Most recent research efforts in the study of children's emo- tional development have either traced the developmental time- table of spontaneous facial expressions or documented the abil- ity of infants and children to discriminate and recognize facial expressions. In general, the underlying model of such research has been biological (Darwin, 1872; Ekman, Friesen, & Ells- worth, 1972; Emde, Gaensbauer, & Harmon, 1976; Izard, 1977; Tomkins, 1962, 1963). Consequently, research has fo- cused on the constant, universal, and holistic aspects of sponta- neous facial expression. However, the ability to voluntarily pose facial expressions is important to issues in the socialization of emotion; for example, the issues of when and how well children can modulate and con- trol their emotional expressions (Lewis & Michalson, 1983). Such ability seems to be a basic skill underlying more complex types of emotional management techniques, such as the mask- ing of facial expressions in order to conform to display rules or to practice deception (Ekman, 1985; Saarni, 1985). Develop- mental research on any aspect of expression management is scarce, but it seems likely that developmental differences exist even in the ability to pose faces. It has been shown that some expressions are easier to pose than others, even among adults (Thompson & Meltzer, 1964). Similar, and perhaps other, age- This research was supported by a W. T. Grant Foundation grant to Michael Lewis, National Institute of Child Health and Human Develop- ment Grant 17205 to Margaret Wolan Sullivan, and a Rutgers Medical School Summer Fellowship to Arthur Vasen. We wish to thank Norma Goetz for data collection and Despi Had- zimichalis for general assistance in preparation of the manuscript. Correspondence concerning this article should be addressed to Mi- chael Lewis, Institute for the Study of Child Development/Department of Pediatrics, UMDNJ-Rutgers Medical School, Medical Education Building CN19, New Brunswick, New Jersey 08903. 690 related differences may be observable in children. In this article we are concerned with the production of facial expression (hereinafter referred to as