The purpose of this study was exploratory, from an ecological point of view. The aim was to find out whether and, if so, to what extent, information about the expression of emotion and emotion-related states is detectable through observation of body movement alone. Participants in a full view study observed a diverse selection of spontaneous expressions of emotion, collected on videotape. The events they indicated as being the most reliable expressions of emotion were converted to point-light displays. These displays were likewise shown to a further group of participants. Patterns of relationship between detection of emotion and emotion­ related states for the full view and point-light conditions were found. Firstly, it became evident that indications of such states are reliably preserved from the full view to the point-light displays. Secondly, patterns of clustering were found, which fit well with the "primary" emotions of joyfulness, anger, fear, sadness and surprise. Consistencies or otherwise in perceptions from one condition to the other seem largely due to the extent to which the expresser's body is fully and uprightly shown within the display, the amount of information available for detection of the "other" the expresser may be interacting with, whether or not the flow of expression is interrupted, and the level of activation of body movements. Analysis of the temporal structure of the expressive and perceptive flow, characteristic of events unfolding over time, supports the view that emotions play an important role in human functioning, serving to safeguard goals. Affect is considered in terms of the person­ environment relationship, wherein emotion-related states emerge as part of a context within which various lines of action unfold. "Secondary" emotions seem to exist within this socially and culturally negotiated level of interaction in the environment. It is proposed that the expressive behaviours evident within transformations of body movement unfold over time sequentially, relative to the effectiveness of individual's negotiative interactions with others facilitating progress towards the personal goal.