Using the proper vocabulary.

This paper makes three points. First, inferences from biological and psychological evidence pertaining to psychological constructs must use distinct vocabularies because they represent different phases of a cascade of processes. Second, there are necessarily indeterminate relations between phases of the cascade that begins with an incentive evoking a brain state which, in turn, may generate a psychological reaction and/or action. Finally, all biological and psychological phenomena occur in particular species and specific contexts; hence it is useful to append to every conclusion information on the agent and the setting in which the evidence was gathered. (c) 2007 Wiley Periodicals, Inc.