Not only does this promote positive effects, it also reduces the negative effects usually present in non-collaborative groups such as the free-rider or hitchhiking effect, social loafing, and the sucker effect. The free-rider or hitchhiking effect (Kerr & Bruun, 1983) exists when ‘‘group members exert less effort as the perceived dispensability of their efforts for the group success increases’’ (p. 78). In other words, they feel that the group is doing enough and that they don’t have to contribute. Social loafing (Latane ́ , Williams, & Harkins, 1979) exists when group members exert less effort as the perceived salience of their efforts for the group success decreases. In other words, as the group size increases so does the anonymity and the non-participation. The social loafer differs from the free rider in that the former lacks the motivation to add to the group performance, while the latter tries to profit from others while minimizing essential contributions. Finally, the sucker effect (Kerr, 1983) exists when the more productive group members exert less effort as the awareness of co-members free-riding increases. That group refuse to further support noncontributing members (they refuse to be ‘suckers’) and therefore reduce their individual efforts” (p. 339-40)
