Failure of an alternation--learning test to discriminate between lobotomized and unlobotomized schizophrenics.

An attempt was made to duplicate Rosvold and Mishkin's finding of clear differentiation between groups, using a modified Yerkes Multiple-Choice Test with 23 lobotomized and 22 unlobotomized schizophrenics for whom scores were available on 10-factored aptitude tests and 2 Wechsler-Bellevue scales. Though marked intergroup differences appeared on the aptitude tests, none appeared on the Yerkes test;' score distributions were all but identical, and there was no intergroup difference in perseveration. The Yerkes test was significantly correlated with a Thurstone test. It seemed insensitive to the enduring subtle postlobotomy deficit in schizophrenics demonstrated by factored aptitude tests and in cited studies of alternation learning and multiple-choice learning.