- In the 1930s Louis Thurstone used his own multiple-factor analysis and argued that intelligence is better described by several distinct 'primary mental abilities' than by a single general factor.
- Thurstone identified verbal comprehension, word fluency, number facility, spatial visualization, associative memory, perceptual speed and reasoning.
- Where Spearman emphasised a dominant g, Thurstone initially argued the data could be explained by group factors without a single general ability.
- Thurstone later acknowledged that his primary abilities were themselves correlated, implying a higher-order general factor.
What did Thurstone propose?
In the 1930s Louis Thurstone used his own multiple-factor analysis and argued that intelligence is better described by several distinct 'primary mental abilities' than by a single general factor. He saw the mind as a set of relatively independent capacities.
What are the seven primary mental abilities?
Thurstone identified verbal comprehension, word fluency, number facility, spatial visualization, associative memory, perceptual speed and reasoning. Together they were meant to capture the main dimensions of human cognition.
How did this challenge Spearman?
Where Spearman emphasised a dominant g, Thurstone initially argued the data could be explained by group factors without a single general ability. The two were, in a sense, analysing similar correlations and emphasising different layers of the same structure.
How was the debate resolved?
Thurstone later acknowledged that his primary abilities were themselves correlated, implying a higher-order general factor. This convergence β group abilities sitting beneath a general factor β anticipated the hierarchical models, like CHC, that dominate today.