Theory of Intelligence # 5. Hierarchical Theories:

British psychologists like Cyril Burt (1949) and Vernon (1960) gave an alternative scheme for the organisation of factors. At the top of the hierarchy, Vernon places that ‘G’ factor or the general cognitive factor. At the next level he places two broad group factors, corresponding to verbal-educational (v: ed) and practical-mechanical (k: m.) aptitudes. These major factors may be further sub-divided.

The verbal educational factor may be sub-divided into verbal and numerical sub-factors, and the practical mechanical factor into mechanical information, spatial, and psychomotor ability. At the lowest level of the hierarchy are the special factors. “Such a hierarchical structure thus resembles an inverted genealogical tree, with ‘g’ at the top, ’s’ factors at the bottom, and progressively narrower group factors in between.”

The graphic representation of Spearman’s two-factor theory (A), of the multifactor theory (B), and of the hierarchical theory (C), showing correlated tests is given below:

Vernon’s theory is a compromise formula, between Spearman’s two factors and Thurstone’s multifactor theory. It retains G factor, and relegates Thurstone’s and Guilford’s structure of intellect to sub-ordinate level.