Primary Mental Abilities
As soon as the methods of multiple-factor analysis had been developed to the point where practical application seemed feasible, we started work on such a project. The development of a large battery of fifty-seven tests for various aspects of intelligence was a large undertaking. When this job had been done, the whole battery was given to a group of 240 volunteers in the spring of 1934. Analysis of these records constituted our first attempt to identify primary mental abilities. A short paper on this experiment was published in Psychometrika[29]and a more complete report constituted the first issue in the Psychometric Monograph Series.[30]Although my first text on multiple-factor analysis, The Vectors of Mind, had previously been published (1935), with a development of the concepts of communality, the rotation of axes, and the use of oblique axes, I hesitated to introduce all of these things in the first experimental study. In particular, there was strong advice from Thorndike, Kelly, and other men for whom I had respect, that an oblique reference frame would be completely unacceptable. Instead of proceeding according to my convictions, that first factor study was published with the best fitting orthogonal frame, although we knew about more complete methods. This was an effort to avoid the storm of controversy that we feared in the introduction of so many different procedures in the first experimental study.
In the last fifteen years the identification of primary abilities and traits has proceeded at an entirely unexpected pace. Fortunately the problem has attracted the attention of some mathematicians and mathematical statisticians. A number of the papers are so technical that they are beyond the comprehension of some of the rest of us who were concerned with the development of these methods in their primitive stage.
The correlations of the primary factors can be factored, just like the correlations among tests. When this is done we find several second-order factors. One of these seems to agree very well with Spearman's general intellective factor g. The critics feature our support of Spearman's g, but they ignore the fact that this work represents at least a modest gain in unraveling the complexities of mental organization.
When a number of the primary factors had been identified with some degree of assurance, it was challenging to develop some tests of primary abilities for use in the public schools. We hope that it will be possible to
(317) get teachers and psychologists to describe children in terms of their mental profiles instead of the single intelligence quotient. To develop tests of primary abilities for use in the schools introduces new problems. As usual there is always the limitation of time for psychological testing. The practical question is, then, how many of the primary abilities can be appraised in the amount of time that is allowable for psychological testing in the schools. The pressure is always to reduce to a minimum the time limit for each test so as to cover as many abilities as possible within one or two class periods. We have tried to make practical compromises in this regard in order to make available in the schools our findings about primary mental abilities. The results of these efforts, issued first in a set of tests of primary mental abilities, were distributed by the American Council on Education in 1938. Subsequently the procedures were simplified with various scoring devices and the tests were shortened considerably. The distribution of this test series was taken over by Science Research Associates where Lyle Spencer and Robert Burns are directors. It has been a pleasure to work with these men in the distribution of psychological test material because they have a genuine interest in the scientific values involved and also a realistic recognition of the practical demands in the schools. It was Robert Burns who was largely responsible for initiating the three-year research project on mechanical aptitude which was supported by the Office of Naval Research. In that study we verified rather clearly that the second space factor, identified by Guilford in his factor studies for the Air Force during the war, was the main component in the complex that is called mechanical aptitude.[31]
In all of our studies in psychological measurement and especially in the theoretical and experimental work on the primary mental abilities, I have been very fortunate in having my wife as a partner because she is a genius in test construction and related problems. With the assistance of Katherine Byrne and Katherine Vitato, she assembled a set of seventy games that could be given to five-year-old children who have not yet learned how to read. These game-tests were given to an experimental population of five- and six-year-old children and a multiple-factor analysis was made of the scores. That unpublished study showed essentially the same primary factors at the kindergarten age which we have found in other studies for adults. A new set of tests was constructed for kindergarten children.www.psychspace.com心理学空间网
