Chapter 10: Personality and Intelligence

Personality is typically measured through assessment of how an individual behaves in a typical manner, often under weak environmental constraints (weak situations), such as assessing Extraversion by asking about the enjoyment of parties. Conversely, intellectual abilities are measured under conditions of maximal performance, where the individual is motivated by a strong environmental press to achieve the best possible results, thereby determining the limits of their performance. While intellectual abilities possess a hierarchical structure characterized by "positive manifold"—meaning all ability measures are positively correlated—ranging from general intellectual ability (G) at the top (Strata III) down to specific abilities (Strata I), personality traits lack this positive manifold and a corresponding single "general personality trait". Research, often drawing from meta-analysis, identifies the strongest associations between abilities and personality constructs that share theoretical overlap with intellectuality, such as Openness to Experience (also termed Culture or Intellectance), which shows positive correlations up to approximately .30 with general intelligence. A more specific measure, Typical Intellectual Engagement (TIE), defined as an individual’s preference for or aversion to intellectual activities, correlates significantly (r = .35) with crystallized intelligence (accumulated knowledge) but not with fluid intelligence, supporting the idea that personality orientation influences long-term knowledge acquisition. Other broad factors, such as Neuroticism (including Negative Emotionality and Stress Reaction), exhibit consistent, albeit modest, negative correlations with intellectual abilities (around r = -.15 with general intelligence), and the related trait of Test Anxiety shows a significant negative correlation with intelligence (r = -.23). Broad traits like Extraversion and Conscientiousness generally display negligible linear correlations; however, it is hypothesized that the relationship may be non-linear or an inverted-U shape, as the optimal point for functioning may be near the middle of the distribution (e.g., an Ambivert), suggesting standard linear correlations are not always appropriate. Among narrower traits, Need for Achievement shows the most robust positive correlations with intellectual ability (r = .07 to .24). Longitudinal studies and evidence from information-processing tasks suggest that personality, particularly arousal levels in introverts and extraverts, interacts complexly with performance, though these short-term effects may cancel out over the long term. Ultimately, personality traits, tied to typical behaviors, are highly diagnostic of whether an individual will approach or avoid intellectually demanding situations, which in turn significantly impacts the development of domain-specific knowledge over time.