This study attempted to refine the assessment of the effectance of four-year-old children through observation of their play. Two scales were developed; the first scale defined organization, involvement, and interpersonal responsiveness in play while the second operationally defined psychosexual content of play. The results confirmed the validity and reliability of the instruments (which are reprinted in an Appendix) as measures of children's effectance and their capacity as learners. (Author/EH)