At a theoretical level, preference for complexity was considered within the framework of creativity with the emphasis upon self-actualization as opposed to productivity. The experimental work can be divided into three main sections. I. A developmental sample of 284 children, aged from 6 to 18, and 64 parents stated their preferences to three measures comprising stimuli varying in complexity: the Revised Art Scale (RA) of the Welsh Figure Preference Test, Berlyne's Figures, and the Random Polygons, the principal score on the latter measure being the Polygon X or the average of the number of points on the figures the subject liked. In general, there is consistency of simplicity—complexity preference. Therefore, it seems more reasonable to propose that such preference taps an underlying simplicity—complexity dimension of personality. Additional evidence relevant to the construct validity of complexity preference as an index of self- actualization was provided by the study with the 53 ESN children and the study with the 19 fifth-form art students. Separating the sample into developmental subgroups, it was seen that the 6- to 7- year-olds and the adults tended to prefer less complexity on the RA and Berlyne's Figures; however, between the ages of 8 and 18, there was little change in complexity preference. The majority of subjects liked a moderate amount of complexity, that is, had scores falling within the medium range (1O-14) on the Polygon X. Furthermore, on the basis of cluster analyses, which aligned the RA, Berlyne's Figures, and the Polygon X in low, medium, and high terms, the largest number of subjects were placed in the medium scoring clusters. II. Impression Formation Tests, one suitable for children and one for adults, were administered for the purpose of discovering whether complexity preference indicates that an individual attempts to structure complexity. For the 231 children tested, no relation emerged between complexity preference and impression formation ability. For the 64 adults, positive correlations occurred between impression formation ability and complexity preference on the RA and Berlyne's Figures. Reasons for the disjunction between the children's and the adults' results were discussed. III. Responses of parents in relation to those of their children were also examined. It was suggested that it might be important to take account of the effect of both parents, as a family entity, upon the child’s complexity preference. Throughout, the findings have been interpreted with a view to the lines which future research might profitably take