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The Eysenck Personality Questionnaire (EPQ) is a three dimensional personality assessment tool that was preceded by an overlapping two-dimensional measure called the Eysenck Personality Inventory (EPI). The EPI was developed by Hans and Sybil Eysenck[1] to measure the two broad dimensions of Extraversion-Introversion* and Neuroticism-Stability. These two 24-item measures were supplemented by a 9-item Lie scale in an attempt to guard against various concerns about response style. Both of these dimensions (Extraversion and Neuroticism) were introduced (and since emphasized) as temperamental aspects of personality that are inherited and evident at birth (i.e., not learned).

The EPQ was introduced as a substantial revision to the EPI in 1975[2] and a further revision (including the items) was published in 1985[3]. The EPQ was designed to be consistent with Hans Eysenck's theoretical model[4,5], which has since come to be known as the P-E-N model. As suggested by this acronym, the EPQ introduced a third dimension measuring Psychoticism. Items on the Psychoticism scale address traits such as aggressiveness, assertiveness, and being egocentric, manipulative, and unsympathetic. As noted by Porzio[6], part of this theory of Psychoticism comes from the knowledge that “a person will exhibit some qualities commonly found among psychotics, and that they may be more susceptible, given certain environments, to becoming psychotic.” Some of these psychotic tendencies might include “recklessness, disregard for common sense, and/or inappropriate emotional expression.”

A second important change relates to the operationalization of Extraversion. The consequences of this important change are evaluated in detail by Rocklin & Revelle[7]. In essence, many of the Extraversion items in the EPI were dropped from the Extraversion scale in the EPQ (and the EPQ-R), leaving only items that relate to Sociability. This difference is noteworthy in that it fails to assess the prominence of arousal as a hallmark of Extraverted behavior.

The EPQ and EPQ-R also differ from many other personality questionnaires in that they use “Yes” and “No” response options instead of a 5- or 6-point Likert-type scale. Items take the form of questions like “If you say you will do something do you always keep your promise, no matter how inconvenient it might be to do so?” or “Do you often need understanding friends to cheer you up?” A reliability study conducted in 2001 reported that scores on the Neuroticism/Stability and Extraversion/Introversion scales tended to be more reliable than the Psychoticism scale. Several researchers[8] have noted the need for more narrowly defined facets of the Psychoticism scale and this is supported by the relative lack of internal consistency in Psychoticism compared to Extraversion and Neuroticism

How much do you know about your own personality? Interested in finding out more? Take our SAPA personality test and see where you fall on the Big Five distributions!

Footnotes:
* Before looking up the proper spelling of ExtrOversion, be sure to read this wonderful post by Scott Barry Kaufman at Scientific American.

References:
[1] Eysenck, H. J. & Eysenck, S. B. G. (1968). Manual for the Eysenck Personality Inventory. San Diego: Educational and Industrial Testing Service.
[2] Eysenck, H. J. & Eysenck, S. B. G. (1975). Manual for the Eysenck Personality Questionnaire. San Diego: Educational and Industrial Testing Service.
[3] Eysenck, S. B. G., Eysenck, H. J. & Barrett, P. (1985). A revised version of the Psychoticism scale. Personality and Individual Differences, 6(1), 21-29.
[4] Eysenck, H. J. (1981). A model for personality. Berlin: Springer-Verlag. [5] Eysenck, H. J. (1991). Dimensions of personality: 16, 5 or 3? — Criteria for a taxonomic paradigm. Personality and Individual Differences, 12(8), 773-790.
[6] Porzio, S. K. (2004). A critical review of Eysenck's theory of psychoticism and how it relates to creativity. Unpublished manuscript.
[7] Rocklin, T., & Revelle, W. R. (1981). The measurement of Extraversion: A comparison of the Eysenck Personality Inventory and the Eysenck Personality Questionnaire. British Journal of Social Psychology, 20, 279-284.
[8] Caruso, J. C., Witkiewitz, K., Belcourt-Dittloff, A., & Gottlieb, J. D. (2001). Reliability of scores from the Eysenck Personality Questionnaire: A reliability generalization study. Educational and Psychological Measurement, 61(4), 675-689.

This page last modified on December 8th, 2016.