The purposes of this study were to assess the attitudes of preschoolers toward two types of handicapping conditions (mental retardation and physical disabilities), and to explore the underlying social reasoning used by young children to formulate/support their perceptions. Sixteen 3- and 4-year-old boys and girls were presented with two 8-1/2" x 11" photographs. One photograph pictured a physically handicapped young boy (age 7 years) using crutches and leg braces, and the other photograph pictured a 9-year-old girl with Tuberous Sclerosis, a condition frequently associated with mental retardation. Each subject was then individually asked a series of questions constructed to elicit his/her social understanding and attitudes towards handicapping conditions. Statistical and content analysis indicated that only two subjects (both girls in the older age group) with prior exposure to handicapped people identified the children in the photographs as handicapped. Most subjects failed to notice anything different about either handicapped child. Those who identified the handicapped boy as "different" responded to the crutches as signifying a broken leg or other resolvable problem rather than a permanently disabling condition. Those who identified the retarded girl as "different" responded to the facial tubercles and general unkempt appearance by describing her as "dirty", but attributing this to a temporary situation correctable by cleanliness. These results suggest that the egocentric thought patterns of young children may make them unaware of handicapping conditions, and that perceptions of handicapped people may first be learned from adult attitudes and behaviors. Suggestions for further research in this area are discussed, and a copy of the questionnaire used to elicit subjects' perceptions of handicapping conditions is attached. (Author/MP)