Slowness is an abnormality which has been regularly and reliably demonstrated by psychometric tests in patients suffering from all forms of mental illness (Shapiro and Nelson, 1955a). In a previous enquiry we found that it was present in some schizophrenic patients and that those with inappropriate affect showed a greater tendency to it than the others (Harris and Metcalfe, 1956).
Nufferno Speed TestIn this investigation we have used only the Nufferno speed test, which is designed to measure speed as distinct from general level of intelligence.It consists of 19 problems of the Thurstone letterseries type in each of which the patient is presented with series of letters and is required to add at the end of the series the letter which is appropriate to the sequence (Furneaux, 1955(Furneaux, , 1956).Every patient was tested on two versions of equal difficulty. In the first or unstressed version (AA) the patient is allowed to work at his own rate, but in the second or stressed version (AB) the examiner urges him to complete the task as quickly as possible.The score for each version is the mean of the logarithms of the times spent for the completion of the items correctly solved in each version. The higher the score, therefore, the slower the patient.Several workers have applied this test to schizophrenic subjects and all report a tendency for them to be slower than normals (Nelson, 1953;Ogilvie, 1954;Shapiro andNelson, 1955a, 1955b;Broadhurst, 1956 Metcalfe, 1956) showed that those of the patients whose affect was markedly inappropriate were grouped closely together in the slower part of the scale, whereas the scores of the patients with moderately inappropriate affect were scattered over a much greater range. Of the original 40 subjects attempting our test battery, one failed to complete the Nuffemo tests satisfactorily so had to be discarded for our present purpose.