European Journal of Social Psychology Eur. J. Soc. Psychol. 36, 135–146 (2006) Published online 1 December 2005 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/ejsp.293 Non-instrumental voice and extra-role behaviour MICHAEL J. PLATOW 1 *, FRANCESCA FILARDO 2 , LINDA TROSELJ 2 , DIANA M. GRACE 1 AND MICHELLE K. RYAN 3 1 The Australian National University, Australia 2 La Trobe University, Melbourne, Australia 3 University of Exeter, Exeter, UK Abstract The instrumental power associated with voicing opinions to an authority was manipulated to observe the effects upon subsequent discretionary, extra-role behaviours. In two experiments, the provision of non-instrumental voice increased extra-role behaviours above a no voice condition. Experiment 2 also showed that this relationship was mediated by procedural-justice perceptions, but not respect from, or social identification with, the group. The implications of these data for current theory, as well as the possible moderating role of social identification, are discussed. Copyright # 2005 John Wiley & Sons, Ltd. A large body of research now confirms the positive impact that both the application and the perceptions of the application of fairness rules by authorities have on a variety of subsequent attitudes and behaviours of those subject to these rules. Indeed, at least five recent meta-analyses show the positive relationship between fairness perceptions and discretionary pro-social behaviours, organiza- tional commitment, and job satisfaction and performance (Cohen-Carash & Spector, 2001; Colquitt, Conlon, Wesson, Porter, & Ng, 2001; LePine, Erez, & Johnson, 2002; Organ & Ryan, 1995; Rhoades & Eisenberger, 2002). Our interest currently is in the effects that the application of fairness rules has on extra-role behaviours (ERBs; Van Dyne, Cummings, & McLean Parks, 1995). These behaviours are ‘discre- tionary’, yet still ‘promote the group’s goals’ (Tyler & Blader, 2000, p. 7). They can consist of, inter alia, pro-social behaviours such as helping (Van Dyne & LePine, 1998), altruism, courtesy, conscientiousness (Organ, 1988), and cooperation (Tyler & Blader, 2000). Although each of these can conceivably be mandated, their un-mandated enactment remains informative because it represents the free choice of individuals and group members to go beyond what is expected of them to contribute to the greater goals of the group, potentially at their own personal expense. As such, these behaviours Received 19 August 2004 Copyright # 2005 John Wiley & Sons, Ltd. Accepted 18 March 2005 *Correspondence to: M. J. Platow, School of Psychology, The AustralianNational University, ACT 0200, Australia. E-mail: michael.platow@anu.edu.au Contract/grant sponsar: Australian Research Council; contract/grant number: A00000970.