Adding a new member to a working group can create distrust between members and hinder group functions, but a new study suggests that the distrust created is between older group members rather than about the newcomers- especially when previous group performance with just the older group members is poor. The results are part of a study published January 30 in the open access journal PLOS ONE by Matthew McCarter and Roman Sheremeta from Chapman University (U.S).
Previous studies report that changing members in an existing group hurts group performance, but the underlying reasons have been unclear. To identify these, the researchers in this study asked participants to play a 4-person coordination game. After a group had played, two members of the group were replaced and the newly formed group asked to repeat the game.
The authors found that replacing old group members with new individuals decreased trust across the group, which caused a drop in the group's performance. This effect was mitigated if the group knew the newcomers' performance history, but only if the new members also knew the older members' history.
Explore further: I totally empathize with you ... sometimes: Effects of empathy on ethnic group interactions
McCarter MW, Sheremeta RM (2013) You Can't Put Old Wine in New Bottles: The Effect of Newcomers on Coordination in Groups. PLoS ONE 8(1): e55058. doi:10.1371/journal.pone.0055058