Reality Monitoring and Metamemory in Twins and Friends

The current study examined source memory/reality monitoring ability and metamemory accuracy in same-sex twins (n = 60) versus friends (n = 49). Dyads were provided a series of actions and imaginings followed by a reality monitoring and metamemory test that included both reality monitoring questions and appraisals of the likelihood of having made a memory error. There were no significant differences between twins and friends on the number of correct performed action items recalled, but twins were more likely than were friends to confuse whether they or their co-twin was the subject of the imaginings. Friends were more apt than twins to accurately appraise the likelihood of having made a memory error. Implications for twins as eyewitnesses are discussed.