Journal oj Consulting and Clinical Psychology 1975, Vol. 43, No. 1, 101
Factor-Defined Abilities in Patients with Unilateral Brain Lesions Abigail B. Sher Michigan State University The purpose of this study was to explore the application of a number of tests of factor-defined abilities to the question of performance differences in patients with unilateral brain lesions, A battery of four tests adapted from the structure of intellect (Guilford, 1967) model of differential abilities was administered to three groups of adult subjects—one group with brain lesions apparently confined to the right cerebral hemisphere (n = 24), one group with brain lesions apparently confined to the left cerebral hemisphere (n = 24), and one group with no history of cerebral disease or nervous disorder (n = 24). The four tests of cognition differed in contents—semantics and figural—and in products —units and classes. Using these tests as operational definitions o%f specified intellectual functions and allowing response time to vary, the current theories relating these functions to focal brain lesions were examined. The results of the study were consistent with a theoretical position including aspects of the two neurological theories—holistic and regional localization—which have historically dominated research in this area. Specifically, it was found that both brain-damaged groups exhibited slower response time than the normal group on all four ability tests. This finding is consistent with a
holistic or mass action theory of brain functioning and is supported by the research on reaction time differences in persons with cerebral disease. In addition, it was found that there was an association between locus of lesion and performance on the test, cognition of semantic units. This finding is consistent with a theory of regional localization of brain function. Moreover, a finding of differential patterns of error choices for the two brain-damaged groups was suggestive of breakdown in information processing stages, The breakdown in stages appeared to be differentially associated with and localized in the two cerebral hemispheres. This last finding provided additional evidence for a regional localization theory. The findings of this study comprised an insufficient answer to the question of the advantages of tests of factor-defined abilities over tests of global intelligence. In particular, the problem of separating language-free from languagedependent performance was not alleviated by the factor-defined tests any more than it was by the "nonverbal" intelligence tests. The failure of factor-defined tests to distinguish behaviors that appear to be factorially distinct in normal populations brings into question the construct validity of these tests, particularly the figural ones.
Reprints and an extended report of this study may be obtained without charge from Abigail B, Sher, Office of Medical Education Research and Development, 206 East Fee Hall, Michigan State University, East Lansing, Michigan 48824.
REFERENCE Guilford, J. P. The nature of human intelligence. New York: McGraw-Hill, 1967. (Received February 28, 1974)
101
Factor-Defined Abilities in Patients with Unilateral Brain Lesions Abigail B. Sher Michigan State University The purpose of this study was to explore the application of a number of tests of factor-defined abilities to the question of performance differences in patients with unilateral brain lesions, A battery of four tests adapted from the structure of intellect (Guilford, 1967) model of differential abilities was administered to three groups of adult subjects—one group with brain lesions apparently confined to the right cerebral hemisphere (n = 24), one group with brain lesions apparently confined to the left cerebral hemisphere (n = 24), and one group with no history of cerebral disease or nervous disorder (n = 24). The four tests of cognition differed in contents—semantics and figural—and in products —units and classes. Using these tests as operational definitions o%f specified intellectual functions and allowing response time to vary, the current theories relating these functions to focal brain lesions were examined. The results of the study were consistent with a theoretical position including aspects of the two neurological theories—holistic and regional localization—which have historically dominated research in this area. Specifically, it was found that both brain-damaged groups exhibited slower response time than the normal group on all four ability tests. This finding is consistent with a
holistic or mass action theory of brain functioning and is supported by the research on reaction time differences in persons with cerebral disease. In addition, it was found that there was an association between locus of lesion and performance on the test, cognition of semantic units. This finding is consistent with a theory of regional localization of brain function. Moreover, a finding of differential patterns of error choices for the two brain-damaged groups was suggestive of breakdown in information processing stages, The breakdown in stages appeared to be differentially associated with and localized in the two cerebral hemispheres. This last finding provided additional evidence for a regional localization theory. The findings of this study comprised an insufficient answer to the question of the advantages of tests of factor-defined abilities over tests of global intelligence. In particular, the problem of separating language-free from languagedependent performance was not alleviated by the factor-defined tests any more than it was by the "nonverbal" intelligence tests. The failure of factor-defined tests to distinguish behaviors that appear to be factorially distinct in normal populations brings into question the construct validity of these tests, particularly the figural ones.
Reprints and an extended report of this study may be obtained without charge from Abigail B, Sher, Office of Medical Education Research and Development, 206 East Fee Hall, Michigan State University, East Lansing, Michigan 48824.
REFERENCE Guilford, J. P. The nature of human intelligence. New York: McGraw-Hill, 1967. (Received February 28, 1974)
101
