A tentative formulation suggesting qualitative differences between process and reactive schizophrenics is presented. The cognitive deficit of reactive schizophrenics is seen as due to fragmentation of relatively normal thinking under stress or during acute disturbance (i.e., on admission). The fragmentation is suggested to result from interference due to excessive responsiveness to external stimuli and task demands. The process schizophrenics are viewed as idiosyncratic (underdeveloped) in thinking with their performance hampered by emotional withdrawal and disruption from internal stimuli. Interactions of the process-reactive dimension with stress conditions and institutionalization are inferred, since reactives' performance should vary with stress and time since admission, while process' performance should remain consistently low. Results of 11 studies from the context of the position arc presented.