A study was conducted to examine patterns of information processing over time in self-analytic groups. Communication patterns in two 25-member groups of college students that met for 32 50-minute sessions were categorized by means of the Systems Information Processing Analysis (SIPA) category system. Messages were coded on four dimensions of information processing: (1) source of information, (2) time orientation, (3) evolution of information, and (4) reduction of equivocality. The sequence of coded messages was then measured for fit with a first order Markov chain model. The results indicated that the communication data from the two groups were first order, that the groups were nonhomogeneous, that stereotypy (predictability of patterns) was low to moderately high across the four dimensions, and that patterns in the evolution-of-information dimension were stationary or stable over time. Patterns in the three other SIPA dimensions were nonstationary (time dependent) for both groups, suggesting cyclical stages of development. (Author/FL)