Understanding the combination of memory variables: a re-examination

This study was a direct prolongation of a study by Wellman, Collins, and Glieberman (1981), which showed that, provided a sufficiently sensitive methodology is used, it is possible to demonstrate experimentally that even 5-year-old children are capable of integrating two types of information--effort and difficulty of task--in their judgment of performance (number of items recalled). We prolonged this study by adopting Anderson's information integration methodology in order to provide evidence concerning the type of combinatorial rule describing subjects' use of both pieces of information and to refine analysis to the individual level. In terms of group results, it was possible to describe the algebraic aspects of the information integration process by an additive model in children and adolescents, and by a multiplicative model in adults. Conclusions changed considerably, however, when individual results were studied. In the 5- and 8-year-old children, the dominant rule was clearly unifactorial, involving effort. Only in the adult group was true integration seen in all subjects.