Thurstone’s 7 Primary Mental Abilities: A Deep Dive
Thurstone’s Theory of 7 Primary Mental Abilities, which emerged in the 1920s, is one of the most important psychological models of intelligence in existence. Louis Leon Thurstone (1887-1955) is considered one of the most influential authors in the field of psychometry. His main contribution is his theory of the 7 primary mental abilities, which opposed the unitary and hierarchical models of intelligence proposed by other pioneers such as Charles Spearman or P. E. Vernon.
Thurstone denied the existence of a general intelligence factor (the famous “g factor”) to which all other cognitive abilities would be subordinated. For this author, intelligence was to be understood as a set of primary mental abilities not reducible to a single top-level dimension.
Along with authors such as Charles Spearman and Raymond B. Cattell, Thurstone is considered one of the main figures responsible for the establishment of factor analysis methods in psychology. These mathematical tests aim to identify the number and structure of the different factors that influence some type of psychological measure.
The influence of Thurstone’s work has been very noticeable in later developments in the psychology of intelligence. Thus, we can find inspiration for the model of primary mental abilities in the most recent versions of such important tests as the Wechsler Intelligence Scales and the Stanford-Binet Intelligence Scale.
Thurstone’s goal was to find an intelligence configuration that was true to the empirical data but kept as simple as possible. That is to say, he tried to explain the different skills that make up intelligence with a few higher-order factors. Each of them had a strong correlation with a particular type of intellectual evidence.
The 7 Primary Mental Abilities
Verbal Comprehension (V)
The verbal comprehension factor is associated with knowledge related to language in all its manifestations. It would therefore include vocabulary, semantics, syntax, and pragmatics. The tests that weighted in factor V include tests of reading comprehension, ordering of text segments, spelling, verbal analogies, etc.
Numerical Aptitude (N)
Numerical aptitude tests consist primarily of basic mathematical calculations: addition, subtraction, multiplication, and division. Although they can be more complex, factor N is mostly weighted for simple arithmetic tasks. The most relevant aspects are the speed of operations and the precision of responses.
Verbal Fluency (W)
This ability can be defined as a person’s capacity to emit coherent and structured verbal sequences quickly and naturally. To measure it, various types of tests that involve rapid speech production are used. For example, the classic test of giving animal names that begin with a certain letter could be used.
Spatial Aptitude (S)
The S factor is manifested in spatial orientation, in the representation of objects in space, or in rotation tasks. Since these are very broad capabilities, spatial fitness is often divided into two or three secondary factors. The relevant tests involve the prediction of movements and the comparison of figures from different perspectives.
Associative Memory (M)
This factor is associated with a specific aspect of memory: the ability to retain element pair associations. Thus, to measure associative memory, tests involving images, words (in visual or auditory format), symbols, etc. are used. They can be presented in the same modality or in combinations of more than one of these materials.
Speed of Perception (P)
In the P factor, all those cognitive tests are based on the comparison between different elements or in the identification of structures and sequences. Therefore, the aptitude that Thurstone called “speed of perception” refers to the speed with which we find the similarities and differences between various items.
General Reasoning (R) or Induction (I)
Some of the research that has been carried out on the Thurstone model distinguishes in part the R factor from the I factor. While the second corresponds to the capacity for inductive thinking (finding general rules with predictive value from series of elements), “general reasoning” has a more marked mathematical weight.