Focusing on the impact of participant characteristics on learning, this study investigated whether certain teaching methods are more effective than others in changing the knowledge and attitudes of adults with specific personality profiles. A total of 117 persons from each of five sections of a course ("Coaching and Developing Individuals") developed by the Industrial Relations Center, University of Chicago, were classified into four personality types: high extraverted, highly neurotic (HE/HN); highly extraverted, less neurotic (HE/LN); less extraverted, highly neurotic (LE/HN); less extraverted, less neurotic (LE/LN). Members of these categories were randomly divided between lecture and case discussion groups. Pretests and posttests of proficiency were given. It has been hypothesized that discussion would work better than lectures with relatively extraverted and stable people (including HE/LN types), while lectures would supposedly work best with introverts and more neurotic (including LE/HN) types. Findings failed to prove or disprove the hypotheses. The Eysenck theory (highest participation by HE/HN types, lowest participation by LE/HN persons) was not supported either. Implications for further research were also noted. (LY)