(Received 18 December 2006; accepted 16 June 2007)

The starting point of this article is that the concept of “vitality affects” is, on the one hand, very important, but, on the other, not precisely defined. The concept and its development are traced in the writings of Daniel Stern, the person who introduced the concept into practice. Three periods of Stern's conceptual development are differentiated here, and an attempt is made to summarize them as certain basic types. By this means, it is shown that vitality affects are defined in relation to most areas of developmental psychology (the neuropsychological, the bodily, the conscious, and the interactional), and that the concept is thereby extended to so many areas that it tends toward disintegration. As final remarks, those qualities of the concept that we find most constructive, especially if one desires to approach the area empirically, are highlighted.