The purpose of the present research was to show how social identity theory
can be applied to enhance individual productivity within groups. Three expe
riments manipulated in-group identifiability and importance of the group fo
r one's social identity, and compared individual's productivity when workin
g alone to when working in a group setting. The group setting in the first
study involved either a collective of unrelated individuals, a group of par
ticipants expecting future interaction, or a group working for a group rewa
rd. The second study compared productivity in groups with four differing in
terdependent reward structures. The final study examine the impact of group
members wearing a common uniform (vs. no uniform) and the presence (or abs
ence) of an out-group. Results supported the general prediction that group
productivity would be enhanced by factors that increase group categorizatio
n and the importance of the group to members' social identities (future int
eraction, interdependent reward structure and uniform/outgroup present). Ho
wever, productivity in groups was not influenced by perceptions of the task
or identifiability of performance. These findings extend social identity t
heory by suggesting that group members will increase their in-group positio
n through individual work efforts.