An investigation of the relationship between appearance and psychological development is presented in this paper. The central hypothesis of the investigation is that appearance is an important stimulus property in the psychological development of children, and as such has an effect on an individual's response to his environment as well as the environment's response to that individual. Children are thought of as possessing stimulus as well as response properties, and development is viewed as a function of the interactions of the child and the environment. The results of the investigation support a hypothesized relationship between stimulus properties and psychological development--that appearance, self-concept, peer acceptance, IQ, and report card grades are all related. The stimulus property is related to the performance dimension characterized by IQ, total report card, and total achievement scores. The stimulus qualities of a child are variables that not only relate empirically, but logically. The data received may be interpreted in the following way: attractive children tend to have higher IQ's, more friends, better self-concepts, and more favorable report cards than their less attractive peers. The variables, represented by the stimulus property dimension, are moderately correlated with the performance dimension. One of the limitations of this investigation is that the social status of the children was ignored. Other studies have shown achievement differences to exist within different social strata. It is possible that appearance and socioeconomic status are positively correlated to a high degree, and that the socioeconomic status should also be considered as part of the stimulus dimension. (MM)