Observational and theoretical terms in psychology: A cognitive perspective on scientific language.

This article presents an empirical, psychological approach to the distinction between observational and theoretical terms, a persistent and unresolved issue in the study of science. Using relevant theory and evidence from cognitive psychology, we show that the observational–theoretical distinction parallels the concrete–abstract distinction in natural language, that both follow from the dual coding assumption of distinct verbal and nonverbal cognitive systems, and that natural language research supports this view. We report similar evidence for 72 psychological terms that were rated by psychologists on observability, consistency of meaning, and other relevant attributes. The ratings correlated highly with one another and also with imagery reaction times and reports of spontaneous imagery. The evidence challenges the claim that all scientific terms are equally inferential and reliable and is consistent with empiricist views of science that emphasize the distinct properties of concrete, observational terms and abstract, theoretical terms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)