Another take on the matrix: interactionism.

This response to C.R. Snyder and T.R. Elliott's article, "Twenty-First Century Graduate Education in Clinical Psychology: A Four Level Matrix Model" (this issue, PP 1033-1054), focuses on the importance of three types of interactions: between mind and body, humans and machines, and individuals and groups. It is proposed that the clinical psychology training programs of the future will need to ensure that their students are well versed in the relevance of these interactions for understanding human behavior and developing effective treatments.