How do people remember things in relationships and groups? Each person doesn't need to remember everything the group needs to know, after all, if each person merely stores in memory information about who is likely to have a particular item in the future. This capacity for remembering who knows what is the key to transactive memory as introduced by Wegner, Giuliano, and Hertel (1985) and Wegner (1986). Transactive memory suggests an analysis not only of how couples and families in close relationships coordinate memory and tasks in the home, but how larger groups and organizations come to develop "group minds," memory systems that are more complex and potentially more effective than those of any of the individuals that comprise them.