Achievement Motivation, Expected Coworker Performance, and Collective Task Motivation: Working Hard or Hardly Working?' zyx JASON W. HART^ STEVEN J. KARAU zyxw Indiana University of Pennsylvania Southern Illinois University at Carbondale MARK F. STASSON Metropolitan State University NATALIE zyx A. KERR James Madison University Social loafing is the tendency of individuals to work less hard collectively than individu- ally. The present study examined the joint influence of achievement motivation and expected coworker effort on collective task performance. Participants zyxw (N= 107) who qual- ified and were available after pretesting on an achievement motivation scale were ran- domly assigned to a work condition and coworker effort condition. Dyads were asked to generate as many uses for a knife as possible within a 12-min time pcriod. Participants low in achievement motivation engaged in social loafing, but only when expected coworker effort was high, whereas participants high in achievement motivation did not engage in social loafing, regardless of expected coworker effort. The implication of achievement motivation for collective task performance settings is discussed. Because groups and teams are taking on increasing importance in today's organizations (e.g., Guzzo zyxwvu & Salas, 1995; Sundstrom, De Meuse, & Futrell, 1990), it is vital to understand what factors either enhance or detract from group performance and group member motivation. Common sense may suggest that working in groups should energize individuals and enhance their motivation and performance. For example, companies often rely on brainstorming sessions to come up with ideas for selling their products, with the assumption that working with others creates a synergy that will enhance group members' individual con- tribution to the process. However, a large and growing body of research has demonstrated that individuals have a tendency to engage in social loafing when working on collective tasks. In formal terms, social loafing is a reduction in an individual's motivation and effort when working collectively as compared to either working individually or coactively (Le., individually, but in the presence of others who are working on the 'The authors thank Robert Helmreich for his helpful comments on an earlier version of this ?Correspondence concerning this article should be addressed to Jason W. Hart, Department of' manuscript. Psychology, Indiana University of Pennsylvania, Indiana, PA 15705. E-mail: jhart@iup.edu zyx Journal of zyxwvuts Applied Social Psychology, 2004, 34, 5, pp. 984-1 000. Copyright zyxwvuts 0 2004 zyxwvut by V. H. Winston & Son, Inc. All rights reserved.