The concept of strength in the analysis of verbal behavior.

A textual analysis of the concept of strength is presented, based on patterns of its occurrence in the book Verbal Behavior (Skinner, 1957). A manual count was conducted of all instances of the word "strength," and closely related forms. Rates were then plotted and interpreted as revealing the kinds of situations where strength is most relevant. Strength appears to be most relevant (as measured by instances per page of text) whenever a detailed behavioral analysis involves 1) more than one source of strength for a response, 2) multiple responses or fragments being strengthened by one or more variables, 3) dynamic changes in behavior, or 4) behavior which is not currently or readily observed. Further research is needed to evaluate how textual analysis of this sort contributes to a science of behavior.