Van Vugt, M. and De Cremer, D. (1999).  Leadership in social dilemmas: Social identification effects on collective actions in public goods. Journal of Personality and Social Psychology, 76 , 587-599. 

Abstract:

Two experimental studies investigated the role of group identification in the selection of and cooperation with leaders to manage public good dilemmas. The findings of the 1st study revealed that there was a general preference to select leaders with a legitimate power base (i.e., democratic, elected, and internal leaders), but these preferences were particularly pronounced when people's identification with their group was high rather than low. The 2nd study complemented these findings by showing that when group identification was low, an instrumental leader (i.e., who punishes noncontributing members) was far more efficient than a relational leader (i.e., who builds positive, intergroup relations) in raising contributions. Yet, when group identification was high, both leader types appeared to be equally efficient.