The intention of this speculative statement is to review and revise a position outlined some years ago in various forms. According to this view, instructive action (or teaching) is not a matter accidental to the scientific practice of psychology, but rather the essential concern, being the currency of the single message exchange system that constitutes human action. It is possible then to look at some of the relevant evidence that psychological science provides, and to suggest that possibilities for effective use in instructional practice may follow from seeing psychologists’ actions as instructive activity, not merely for their peers, who are the audience for their words, but in connection with their essential role in this larger context of the single message exchange system and thence to the subsystems of the larger context in which social schemes guide action. It is thought that the debate produced by the call for evidence-based practice in education may be helped by consideration of this view that would place instructive activity at the centre of things. Some problems are identified for psychologists and teachers and some general suggestions are made about seeking a dynamic balance of forces and connection of levels in an interactive scheme where the activities of each party might produce evidence bearing upon the plans for action of the other.