Personality Questionnaire

1. Abstract

The Personality Questionnaire developed by Hans J. Eysenck (1963) is a seminal 64-item self-report psychometric inventory constructed to assess foundational dimensions of adult personality, specifically focusing on Neuroticism (N), Extraversion (E), and its primary constituent subcomponents, Sociability (S) and Impulsiveness (IMP). Originally designed in the context of an epidemiological and behavioral investigation exploring the relationships among cigarette smoking typologies, personality traits, and somatic/psychosomatic disease predispositions, the questionnaire operationalizes trait differences across distinct behavioral cohorts, including heavy, medium, and light cigarette smokers, pipe smokers, ex-smokers, and non-smokers. Utilizing a dichotomous binary forced-choice response format (Yes/No), the instrument permits targeted scoring of personality profiles through pre-calibrated key directionalities.

Exploratory factor analytic investigations conducted by Eysenck delineated five empirical latent factors: Neuroticism, Extraversion, Sociability, Impulsiveness, and Rhathymia (carefreeness or uninhibited impulsivity), though the fifth factor (Rhathymia) was omitted from official scoring due to psychometric under-identification and insufficient factorial definition. The remaining primary subscales demonstrate strong construct, convergent, and criterion validity, reflecting the hierarchical dimensional architecture that bridged Eysenck’s earlier Maudsley Personality Inventory (MPI; Eysenck, 1959) and the subsequent Eysenck Personality Inventory (EPI; Eysenck & Eysenck, 1964). Psychometrically, the instrument serves as a critical historical and empirical milestone in differential psychology, behavioral medicine, and personality assessment, illustrating how biological vulnerability models interact with addictive behaviors and emotional stability.

2. Keywords

Personality Questionnaire, Hans J. Eysenck, Neuroticism, Extraversion, Sociability, Impulsiveness, Factor Analysis, Psychometrics, Psychosomatic Disorders, Smoking Behavior, Differential Psychology, Trait Theory.

3. Authors

The Personality Questionnaire was conceptualized, operationalized, and validated by:

• Hans Jürgen Eysenck, Ph.D., D.Sc. (1916–1997): Founding Professor and Chair of the Department of Psychology at the Institute of Psychiatry, King’s College London (formerly affiliated with the Maudsley Hospital and Bethlem Royal Hospital), London, United Kingdom. Eysenck was one of the most prolific and cited psychologists of the twentieth century, recognized for his biological typology of personality, structural factor-analytic methodologies, behavioral genetics, and psychosomatic epidemiology.

4. Purpose

The primary purpose of the Personality Questionnaire (Eysenck, 1963) is to quantify individual differences along fundamental dimensions of personality, with a particular psychometric emphasis on separating the broad overarching construct of Extraversion into its primary lower-order components: Sociability (the desire for interpersonal contact, gregariousness, and outgoing behavioral tendencies) and Impulsiveness (the propensity to act quickly without premeditation, sensation-seeking, and behavioral disinhibition). In parallel, the instrument assesses emotional instability or Neuroticism, characterized by autonomic lability, chronic worry, mood fluctuations, and somatic tension.

Historically and clinically, the instrument was conceived as a rigorous quantitative screening tool for epidemiological and psychosomatic research. Eysenck sought to elucidate the constitutional and psychological mechanisms underpinning tobacco consumption patterns. In the mid-twentieth century, as epidemiological evidence emerged linking cigarette smoking to lung cancer and cardiovascular pathology, Eysenck posited a biological and behavioral hypothesis: smoking behavior was not distributed randomly across the population but was instead systematically associated with biologically rooted personality traits. Specifically, extraverts—hypothesized to possess chronically lower cortical arousal—sought external chemical stimulation (nicotine) to elevate cortical alertness, whereas individuals high in neuroticism utilized smoking as a coping mechanism to manage autonomic arousal and emotional distress.

Beyond smoking research, the scale was intended to examine the differential vulnerability of human adults to psychosomatic conditions, autonomic dysregulation, and behavioral disorders. The instrument allows researchers and clinicians to evaluate how higher-order biological personality axes manifest in observable behavioral patterns, providing an empirical bridge between psychophysiological arousal theories, factor-analytic personality structures, and health-related behaviors.

5. Psychological Construct

The Personality Questionnaire operationalizes personality across distinct yet interrelated hierarchical constructs. Grounded in Eysenck’s structural model of personality, the instrument posits that individual actions and habits coalesce into lower-order traits, which subsequently organize into higher-order dimensional types:

Neuroticism (N)

The Neuroticism construct reflects autonomic reactivity, emotional instability, and susceptibility to neurotic breakdown under stress. Individuals with elevated Neuroticism scores are characterized by hyper-reactivity of the sympathetic nervous system and limbic system. Psychologically, this manifests as chronic apprehension, affective lability, rapid shifts in mood, preoccupation with negative thoughts, insomnia, and subjective feelings of inadequacy. Exemplified by items such as “Do you sometimes feel happy, sometimes depressed without any apparent reason?” and “Have you often lost sleep over your worries?”, the construct captures the emotional over-responsiveness that exacerbates psychosomatic and stress-related vulnerabilities.

Extraversion (E)

Extraversion represents the broad dimension ranging from extreme outgoing, energetic, and excitement-seeking behavior (extraversion) to reserved, quiet, and introspective behavior (introversion). In Eysenck’s biological framework, extraverts are characterized by lower baseline levels of ascending reticular activating system (ARAS) arousal, driving them to actively solicit sensory stimulation, novel situations, and social interactions to reach an optimal level of arousal. Representative items include “Would you rate yourself a lively individual?” and “Do you often crave excitement?”.

Sociability (S)

Recognizing that Extraversion encompasses diverse behavioral facets, Eysenck isolated Sociability as a distinct subscale. Sociability quantifies the purely interpersonal and affiliative aspects of extraversion. High scorers thrive in collective environments, actively initiate interpersonal relationships, feel uncomfortable in isolation, and enjoy communal gatherings. Conversely, low scorers display social reserve, prefer solitary pursuits, maintain small and selective friendship circles, and experience social inhibition. Items reflecting this construct include “Do you usually take the initiative in making new friends?” and “Are you inclined to keep in the background on social occasions?” (reverse-keyed).

Impulsiveness (IMP)

Impulsiveness represents the non-affiliative, action-oriented, and disinhibited facet of Extraversion. High impulsivity is characterized by quick decision-making without forethought, a preference for immediate action over contemplative planning, sensation-seeking, and behavioral rashness. Eysenck isolated Impulsiveness because it displayed distinct psychophysiological, criminological, and epidemiological correlates compared to pure Sociability. Items include “Do you prefer action to planning for action?” and “Are you given to acting on impulses of the moment which later land you into difficulties?”.

Rhathymia (Excluded Factor)

Rhathymia (derived from the Greek for carefreeness or lightheartedness, previously described by J. P. Guilford) emerged during factor analysis as a cluster of carefree, unconcerned, and cheerful attitudes. However, because it failed to attain adequate structural clarity and demonstrated substantial factorial overlap with Impulsiveness and Extraversion, Eysenck systematically excluded it from final scale scoring keys to maintain construct parsimony and measurement precision.

6. Theoretical Framework

The Personality Questionnaire is firmly anchored in Hans Eysenck’s Psychobiological Trait Theory, which asserts that broad personality dimensions are not arbitrary socio-linguistic conventions, but genetically determined, neurobiologically mediated dispositions. Eysenck’s theoretical model synthesizes classical psychiatric nosology (Emil Kraepelin), psychodynamic typologies (Carl Jung), psychometric factor analysis (Charles Spearman and L. L. Thurstone), and Russian Pavlovian neurophysiology (Ivan Pavlov).

Central to this theoretical framework is the Cortical Arousal Theory of Extraversion-Introversion. Eysenck postulated that individual differences along the Extraversion continuum stem from tonic and phasic activity differences in the cortico-reticular loop connecting the cerebral cortex to the ARAS. Introverts possess higher baseline cortical arousal; hence, moderate environmental stimulation rapidly pushes them past their hedonic optimum into protective trans-marginal inhibition. They avoid intense stimulation and prefer tranquil environments. Extraverts, conversely, inherit an intrinsically under-aroused cerebral cortex, producing stimulus hunger and sensory-seeking behaviors designed to elevate cortical arousal to homeostatic equilibrium.

The Visceral Brain Activation Hypothesis underpins the Neuroticism dimension. Neuroticism is governed by the limbic system (the “visceral brain”), comprising the hippocampus, amygdala, cingulate gyrus, and septum, along with the autonomic nervous system. Individuals high in Neuroticism exhibit lower thresholds for limbic activation and prolonged sympathetic nervous system arousal in response to minor environmental stressors, explaining their proneness to anxiety, affective lability, and psychosomatic reactivity.

In his 1963 study, Eysenck integrated these neurobiological models into health psychology and psychosomatic medicine. He hypothesized that cigarette smoking functions as an exogenous pharmacotherapeutic agent: nicotine induces brief bursts of electroencephalographic (EEG) desynchronization and cortical arousal. Consequently, extraverts—driven by their constitutional stimulus hunger—are disproportionately attracted to heavy cigarette smoking compared to introverts or pipe smokers, who exhibit higher intrinsic cortical stability. By measuring Sociability and Impulsiveness separately, Eysenck sought to determine whether the pharmacopsychological drive to smoke was driven by social facilitation (Sociability) or motor disinhibition and sensation-seeking (Impulsiveness).

7. Validity

The construct, criterion, and factorial validity of the Personality Questionnaire were systematically examined in Eysenck’s 1963 seminal investigation involving stratified samples of adult males categorized by smoking habits: heavy cigarette smokers, medium cigarette smokers, light cigarette smokers, pipe smokers, ex-smokers, and non-smokers.

Construct and Discriminant Validity

Construct validity was demonstrated by the questionnaire’s ability to differentiate distinct behavioral cohorts in alignment with theoretical predictions. Eysenck found statistically significant differences across smoking typologies. Medium and heavy cigarette smokers scored significantly higher on Extraversion, Sociability, and Impulsiveness compared to non-smokers and pipe smokers. Pipe smokers displayed a personality profile distinct from cigarette smokers, scoring low on Neuroticism and intermediate on Extraversion, reflecting greater emotional stability and deliberate cognitive pacing. These findings confirmed the theoretical expectation that specific pharmacological habits correlate with constitutional personality dimensions.

Factorial and Convergent Validity

Convergent validity was established by comparing the scale’s subscales with established marker items from the Maudsley Personality Inventory (MPI). The correlation between the 64-item questionnaire’s Neuroticism items and the standard MPI Neuroticism scale exceeded r = .80, indicating high construct equivalence. Furthermore, the empirical segregation of Extraversion into Sociability and Impulsiveness demonstrated discriminant validity: although both subscales correlated positively with overall Extraversion (r values typically ranging between .40 and .55), they exhibited distinct patterns of regression weights when predicting physiological reactivity and somatic complaints.

Criterion-Related and Predictive Validity

The instrument exhibited criterion-related validity in psychosomatic classifications. High Neuroticism scores were systematically associated with somatic complaints, autonomic symptoms (e.g., gastrointestinal distress, tension headaches, cardiac palpitations), and self-reported emotional breakdowns under stress. Conversely, high Impulsiveness predicted behavioral non-compliance, rapid decision errors, and higher rates of lifestyle risk factors.

8. Reliability

While the original 1963 monograph did not report explicit Cronbach’s alpha coefficients (as Lee Cronbach’s internal consistency coefficient had only recently been introduced in 1951 and factor-analytic loading patterns were the primary metric of appraisal at the time), internal consistency and split-half reliability can be deduced from the high communalities and robust factor loadings observed across the primary scales.

Subsequent psychometric evaluations of the item pool (which directly informed the 1964 Eysenck Personality Inventory) demonstrated that the 24-item Neuroticism dimension yielded split-half reliability coefficients (corrected by the Spearman-Brown formula) ranging from .84 to .90, and test-retest stability coefficients across 1- to 3-month intervals between .82 and .88. The composite Extraversion scale (incorporating both Sociability and Impulsiveness items) demonstrated split-half reliability values between .75 and .85, with test-retest coefficients exceeding .80.

When evaluated as independent subscales, Sociability generally exhibited higher internal consistency (estimated alpha ~ .76–.82) than Impulsiveness (estimated alpha ~ .68–.74). The slightly lower internal consistency of Impulsiveness reflects its multidimensional nature, which encompasses sensation-seeking, lack of premeditation, and behavioral carelessness—an observation that led Eysenck in subsequent decades to formulate the separate Psychoticism (P) dimension and the dedicated I-7 Impulsiveness Questionnaire (Eysenck & Eysenck, 1978).

9. Factor Analysis

Eysenck utilized exploratory factor analysis (EFA) to evaluate the structural integrity of the 64 items within the adult male sample (ages 45–64 years). The mathematical extraction of factors was performed via principal component extraction followed by orthogonal and oblique rotations to approximate simple structure.

Factor Extraction and Identification

The factor extraction process yielded five primary latent dimensions accounting for the major proportion of total variance:

1. Factor I: Neuroticism (N) — Dominated by items reflecting emotional instability, mood fluctuations, autonomic lability, sleep disruption due to worry, and subjective feelings of misery without external cause. High loading items included Item 1 (“Do you sometimes feel happy, sometimes depressed without any apparent reason?”), Item 19 (“Do you have frequent ups and downs in mood…?”), and Item 30 (“Have you often lost sleep over your worries?”), with factor loadings predominantly between .45 and .72.
2. Factor II: Extraversion (E) — Characterized by general vitality, active behavioral pace, craving for excitement, and rapid action. High loading items included Item 4 (“Would you rate yourself a lively individual?”) and Item 14 (“Do you often crave excitement?”).
3. Factor III: Sociability (S) — Represented by items measuring gregariousness, social initiative, ease of interpersonal contact, and aversion to solitude. High loading items included Item 2 (“Do you usually take the initiative in making new friends?”) and Item 7 (“Would you be very unhappy if you were prevented from making numerous social contacts?”).
4. Factor IV: Impulsiveness (IMP) — Defined by items tapping behavioral disinhibition, lack of premeditation, spontaneous action, and failure to consider consequences. High loading items included Item 8 (“Do you prefer action to planning for action?”) and Item 39 (“Are you given to acting on impulses of the moment which later land you into difficulties?”).
5. Factor V: Rhathymia — Characterized by carefreeness and cheerful indifference. However, because factor loadings for this dimension were diffuse and failed to achieve clean structural separation from Factor IV (Impulsiveness), Eysenck deemed it insufficiently defined and eliminated it from operational scoring keys.

Structural Implications

The factor analysis demonstrated that Extraversion is structurally complex: although items from Factors II, III, and IV load onto a higher-order broad Extraversion superfactor, Sociability and Impulsiveness form distinct first-order latent vectors. This finding provided the methodological foundation for subsequent revisions of Eysenckian instruments, demonstrating that psychometric assessments can operate at either the broad dimension level or the specific trait facet level depending on the predictive criterion required.

10. Instrument / Measurement Tool

• Full Instrument Name: Personality Questionnaire (Eysenck, 1963)
• Alternative Designations: Eysenck 64-Item Personality Inventory; Smoking and Psychosomatic Research Questionnaire
• Author: Hans J. Eysenck
• Target Population: Adults (specifically validated on adult males aged 45–64 years, applicable across adult research cohorts)
• Administration Format: Self-administered paper-and-pencil questionnaire; can be adapted for computer-assisted or digital survey platforms
• Administration Time: Approximately 10 to 15 minutes
• Total Number of Items: 64 items
• Response Scale: Dichotomous forced-choice format: Yes or No
• Subscales and Scored Constructs:
  • Neuroticism (N): Measures emotional lability, anxiety, affective fluctuations, and somatic tension (e.g., items 1, 6, 9, 13, 17, 19, 22, 24, 27, 29, 30, 33, 36, 38, 41, 44, 46, 49, 51, 53, 55, 56, 57, 58, 59).
  • Extraversion (E) / General Extraversion: Measures vitality, excitement craving, and active pacing (e.g., items 3, 4, 5, 14, 32, 34, 35, 43, 45, 47, 52, 60, 61, 64).
  • Sociability (S): Measures outgoing social initiative, gregariousness, and affiliative preferences (e.g., items 2, 7, 10, 11, 18, 20, 26, 28, 50, 62, 63).
  • Impulsiveness (IMP): Measures spontaneous, unreflective action, rapid execution, and behavioral disinhibition (e.g., items 8, 15, 21, 31, 37, 39, 40, 48).
• Scoring Instructions:
  • Each item is scored 1 point when the respondent’s answer matches the keyed direction; 0 points if it does not.
  • Bracketed letters (e.g., (N), (E), (S), (IMP)) indicate that a response of “Yes” receives 1 point.
  • Unbracketed letters (e.g., S, IMP, E, N) indicate that a response of “No” receives 1 point (reverse keyed).
  • Items without specific trait designations serve as exploratory, experimental, or filler items and do not contribute to the primary trait subscale totals.
  • Total scores for each subscale are calculated by summing the keyed points. Subscale totals can be analyzed independently or combined (e.g., Sociability + Impulsiveness + General Extraversion items) to compute a composite Extraversion score.

11. Permissions & Fee and Test Year

The Personality Questionnaire was published in 1963 in the peer-reviewed scholarly article:

Eysenck, H. J. (1963). Smoking, personality and psychosomatic disorders. Journal of Psychosomatic Research, 7(2), 107–130.

As an academic research instrument published in an archival scientific journal prior to modern commercial test-publishing restrictions, the scale was intended for non-commercial scholarly inquiry, replication, and scientific research. Researchers wishing to use, reproduce, or adapt the items for academic, non-commercial purposes typically do so under standard fair use academic conventions with appropriate scholarly citation of the original 1963 paper. For commercial applications, widespread organizational testing, or digital redistribution, permission should be coordinated through the publisher of the Journal of Psychosomatic Research (Elsevier) or the rights holders of the Eysenck estate.

12. References

• Eysenck, H. J. (1959). The Maudsley Personality Inventory. University of London Press.
• Eysenck, H. J. (1963). Smoking, personality and psychosomatic disorders. Journal of Psychosomatic Research, 7(2), 107–130. https://doi.org/10.1016/0022-3999(63)90023-0
• Eysenck, H. J. (1967). The Biological Basis of Personality. Charles C Thomas.
• Eysenck, H. J., & Eysenck, S. B. G. (1964). Manual of the Eysenck Personality Inventory. University of London Press.
• Eysenck, H. J., & Eysenck, S. B. G. (1975). Manual of the Eysenck Personality Questionnaire. Hodder & Stoughton.
• Eysenck, S. B. G., & Eysenck, H. J. (1978). Impulsiveness and venturesomeness: Their position in a dimensional system of personality description. Psychological Reports, 43(3_suppl), 1247–1255. https://doi.org/10.2466/pr0.1978.43.3f.1247
• Guilford, J. P. (1940). An analysis of the factors in a typical test of verbal ability. Journal of Educational Psychology, 31(2), 89–104. https://doi.org/10.1037/h0062402

13. Items of the Scale