Explain the Spearman’s Two Factor Theory.

The Spearman’s two-factor theory defines critical thinking skills as a combined effect of cognitive abilities and personality dispositions. Although the available research supports the association between critical thinking and measures of cognitive ability, the specific traits contained in the dispositional factor have not been clearly identified through empirical research.

Intelligence has five quantitative principles of cognition: Spearman’s two-factor theory has been criticized for its factor analytic approach being purely psychometric. According to the critics, it is this aspects because which the theory fails to provide a cognitive theory. However, Sternberg and Frensch (1990) came up with arguments in favor of the two-factor theory and convincingly rejected this criticism. Further, another important feature of Spearman’s theory is that it views intelligence as depending on many qualitative principles of cognition.

According to M. W. Eysenck (1990), intelligence depends upon cognative control, fatigue, mental energy, primordial potencies, and retentivity. At the same time, M. W. Eysenck found that Spearman also described five quantitative principles of cognition. These are relevant to intelligence. Using the method of confirmatory factor analysis, Jensen (1998) confirmed the existence of “g”. Further, in her research Carroll (1993) also found the existence of “g” at tratum III in her hierarchical factor analysis.

A very strong criticism against the two-factor theory has been put forward by E. L. Thorndike (1926). According to him, the inter correlations studied by Spearmen were too small to test the question of a common factor. Therefore, he opposed the existence of a characteristic such as general intelligence. According to Thorndike, there are several of separate characteristics that make up intelligence and not one kind of factor.

Arguing against two-factor theory, G. H. Thomson (1939) states that inter correlations between tests are actually the result of common samplings of independent factors and hence there should be a sampling theory according which every test samples a certain range of elementary abilities of the subject. However, favoring Spearman, Guilford (1953) has rejected Thomson’s arguments. According to him, the elements may be demonstrated experimentally.

Further, the legacy of Spearman has been carried out by Thurstone. Thurstone generalized Spearmen’s methods and formulas into matrix algebra and concluded that instead of Spearmen’s “g” factor, seven primary abilities fitted the data much better than the two-factor theory. According to Eysenck (1972), population sampled and choice of tests may be two reasons of this type of apparently conflicting findings by Spearman and Thurstone.