A study was conducted to assess the effects of verbal reinforcement on task performance of black preschool children. Subjects were 36 black children in preschool centers serving families of two income levels. The children were stratified by age, sex, and income level and were randomly assigned to four groups: (1) middle income, praise; (2) middle income, no praise; (3) lower income, praise; and (4) lower income, no praise. A marble-dropping task was performed by each subject. Results of a two-way analysis of variance performed on the data indicated a significant level interaction effect between the praise/no praise treatment and income levels on task performance. Tests of the interaction revealed that middle income children performed significantly better when praised and that lower income children significantly outperformed middle income children when receiving no praise. Under the conditions of the study, praise did not increase performance scores of preschool children but had a differential effect according to their income levels. (Author/WAM)