Shirking, social loafing. and free riding are concepts that have guided the recent study of how much effort employees provide on the job. Although researchers have generally treated these concepts as distinct, a common thread underlies them. that is, propensity to withhold effort (PWE). The main difference among the three concepts is the context in which or the reasons why withholding effort occurs. Building on these ideas, this article applies Knoke's (1990) synthesized motivation model to PWE and suggests that rational, normative, and affective bonding incentives may play a role in employee PWE. Using the model, this article reconceptualizes and attempts to clarify past theory and research, and it develops hypotheses to direct future research on PWE in work groups.