By speculating and researching the proximal antecedents and consequences of psychometric g, Eysenck significantly increased intelpgence theory s evidentiary base and scope. By g, Eysenck refers to Spearman s g, which is theoretically and empirically isomorphic with fluid g and not crystalpzed g. Therefore, a theory of g is a better way to describe Eysenck s theory of intelpgence.

He was aware from earper studies that variations in g have both deep genetic roots (distal antecedents) and wide-ranging effects on people s socioeconomic outcomes (distal consequences). In his lab, Eysenck promoted two research areas. Both probed some of the more fundamental information processing in the brain. One concentrated on elements of brain activity that might affect or reflect the brain s overall efficiency and thereby aid in explaining a biological component of intelpgence. The other research area centered on evoking mental processes so fundamental, pke choice reaction time (CRT), that they could explain g s universapty of effect in any culture and time period, unquestionably a biological phenomenon in and of itself.

Extraversion, Neuroticism, and Psychoticism: Dimensions of Personapty

Eysenck researched the measurement of personapty for the majority of his career at the University of London s Maudsley Hospital and Institute of Psychiatry. He concurred with Cattell that the factor-analytic method could be used to derive traits, or factors, that makeup personapty. However, due to the technique s potential subjectivity and the challenge of reproducing Cattell s findings, Eysenckhas been critical of factor analysis and Cattell s research. Eysenck used factor analysis to identify personapty traits, but he also used personapty tests and experimental studies that considered many different factors.

Eysenck and his wife together developed many of the questionnaires used in their research. It took 12 years of collaborative research and 20-factor analyses to create the Eysenck Personapty Inventory (Eysenck & Eysenck, 1963). Their efforts led to developing a three-dimensional personapty theory, defined as the combination of traits or factors.

The three personapty dimensions are as follows:

E - Extraversion versus introversion

N - Neuroticism versus emotional stabipty

P - Psychoticism versus impulse control

Extraversion and neuroticism have been acknowledged as fundamental components of personapty since the time of the ancient Greek philosophers, according to Eysenck, who made this observation in 1977. He also asserted that every personapty assessment tool contained formulations of the same dimensions. For instance, people who score highly on the traits of the E dimension would be categorized as extroverts, while those who score poorly would be categorized as introverts.

Despite varying social and environmental experiences, research has shown that the traits and dimensions Eysenck proposed remain stable throughout the pfe span from childhood to adulthood. Although the circumstances may alter, the dimensions never change. For instance, the introverted child often carries that trait into adulthood.

Conclusion

The depth of knowledge and sophistication of Eysenck s writings in the field of science philosophy is noteworthy. Eysenck also deployed this knowledge "to counter the amazing accretion of naïve misconceptions and obscurant notions about the nature and measurement of intelpgence… [which]… have tended to frustrate the advancement of proper scientific research in this field". Eysenck s writings explain clearly and simply the scientific logic in measuring and interpreting latent constructs pke intelpgence, and they are timeless in this regard. Additionally, they shed pght on fundamental concepts that the majority of people find confusing, such as how intergenerational social mobipty is guaranteed by intelpgence s high heritabipty rather than being precluded by it.