The behavioral effects of lysergic acid diethylamide (LSD-25) have been studied programmatically in the Clark Laboratories, utilizing the framework of organismic and developmental theory. In the course of testing some of the implications of these theoretical positions, a number of situations have been developed to study space localization. This paper involves the situation dealing with the so-called apparent horizon, i. e., that point in space perceived to be at eye level. This dimension of spatial organization has been studied extensively under various test conditions, e. g., under conditions of success and failure,3 and under conditions of energizing and tranquilizing drugs,1 and for various groups: depressed manic-depressive, and elated manic-depressive groups2; children of various ages,4 etc. Of particular pertinence to the present paper is a developmental study using children of ages ranging from 6 to 20 years.4 In that