The purpose of the present study was to develop an objective index of cognitive slippage, an important sign of vulnerability to schizophrenia. Recent evidence indicating that schizophrenics often fail to consider the needs of their listeners may reflect such a cognitive deficit. In a previous investigation, two sets of multiple-choice test items that presumably tap this problem were developed. Unfortunately, the two sets of items were not equated with regard to variables affecting discriminating power. In the present study, new items were developed, and subsets of each type were matched for mean and distribution of item difficulty and for reliability. The tests were then administered to 37 schizophrenics, 22 patients with affective disorders, and a further sample of 38 normal subjects. The difference scores (for the two types of items) of the schizophrenic patients were greater than those of normal subjects, but the schizophrenics did not differ from the affectively disordered patients. Thus, the previously developed procedure does seem to reflect a genuine cognitive problem rather than a mere statistical artifact. On the other hand, the problem is also observed in some patients with affective disorders that are presumably not part of the schizophrenic spectrum. The value of the tasks will depend on their relationship to other measures of schizotypic traits such as anhedonia.