Previous research has found that decision-making groups do not effectively pool unshared information. This study examined how personal expertise facilitates the mentioning and validation of unshared information in collective recall and decision-making groups by increasing members' awareness of who holds what types of information. Assigned expertise increased substantially the proportion of unshared information mentioned during both collective recall and decision-making tasks. Two results supported the hypothesis that assigned expertise provides validation for the recall of unshared information. When expertise was assigned, (a) more of the unshared information mentioned during the recall task was retained on the collectively endorsed written protocol, and (b) unshared information that was mentioned in discussion was more likely to be correctly recognized by members after group interaction.