A study was conducted to test four hypotheses concerning modification of student self-concept in communication courses: (1) different kinds of training affect student self-concept in different ways, (2) scale bias affects measurement of student self-concept, (3) male and female self-concepts change differently, and (4) course grade affects student self-concept. Four different instruments were administered among subjects drawn from communication, freshman English, psychology, and biology courses. Of the four sections of each course sampled, two sections responded to two scales--one measuring general self-concept and the other measuring self-concept as a communicator. The remaining two sections responded to two different instruments measuring the same variables. Instruments were administered during the first and last two weeks of the semester. The results indicated an increase of scores over the semester for communication and English subjects and a decrease in scores for psychology and biology subjects, supporting the first hypothesis. The results showed that the instruments measuring general self-concept were not highly related to the instruments measuring the dimension self-concept of communication ability, supporting the second hypothesis. The results did not support either the third or fourth hypotheses. (HTH)