This project was concerned with an exploration of the dual (or double) function terms, the elementary and ubiquitous metaphors which use the language of naive physics for the psychological description of people. Theoretical arguments and empirical evidence are presented in support of Solomon Asch's contention that the terms describe interactions which are experienced as formally similar, that is, which are isomorphic. Asch's suggestion that the terms refer to concrete cognitive concepts is amplified and discussed in relation to underlying theoretical issues concerning the nature of perception and its relation to thinking. Special attention in this regard is given to the theoretical perspective of Gestalt psychology and its challenge to traditional atomistic views of perception. A developmental study by Asch and Nerlove (1960) resulting in conclusions contradictory to Asch's original understanding of the dual function terms is considered in detail. The present research re-examines their problematical finding that the dual function terms are acquired as homonyms in a circuitous, piecemeal fashion. 61 elementary school children, ages 6-9, participated in the study. In order to explore the hypothesis that children's difficulties with the dual function metaphors are due primarily to difficulties with the relatively complex and abstract domain of personality description, the children's ability to comprehend and explicate two dual function terms describing personality (persons described as hard and cold) was compared with their understanding of two related synesthetic, or cross-sensory metaphors (colors described as loud and warm). Although more children than anticipated appeared to have had an elementary understanding of one of the personality terms, hard, it was found that the cross-sensory metaphors were generally understood in a more differentiated way and resulted in a significantly greater number of explications of the dual function than the personality terms. The particular kinds of explications that were offered for both personality and cross-sensory metaphors suggested descriptions of formally similar interactions. Responses explicitly describing the terms as homonyms were extremely rare for both types of metaphors. The results indicate that when the metaphors chosen for study describe domains that are more accessible to children's understanding, children appear to be able to both understand and explicate the metaphors. Further, their description of the similarity relation between the terms suggests a description of events experienced as intrinsically similar. (Dissertation Abstracts)