Open Four Temperaments Scales

Abstract

The Open Four Temperaments Scales (O4TS) is a self-report psychometric instrument designed to operationalize and quantify the classical fourfold typology of human temperament—Sanguine, Choleric, Melancholic, and Phlegmatic—within a contemporary differential psychology framework. Developed through the Open-Source Psychometrics Project, the instrument bridges historic humoral personality typology and modern dimensional models such as Hans Eysenck’s two-dimensional model of personality (Extraversion and Neuroticism). The O4TS consists of 24 self-referential items distributed symmetrically across four 6-item subscales: Sanguine (sociability, interpersonal warmth, novelty-seeking), Choleric (assertiveness, interpersonal dominance, emotional reactivity), Melancholic (emotional vulnerability, self-consciousness, introspective sensitivity), and Phlegmatic (emotional equanimity, interpersonal detachment, conflict avoidance). Responses are recorded along a 5-point Likert scale anchored by 1 (Disagree), 3 (Neutral), and 5 (Agree). Psychometric evaluations of large open-access normative samples demonstrate satisfactory internal consistency reliability across subscales, with Cronbach’s alpha coefficients ranging from .71 to .82. Confirmatory factor analyses confirm that a four-factor structure provides an acceptable fit to empirical observations, while convergent and discriminant validity analyses demonstrate predictable correlations with the Five-Factor Model and Eysenckian dimensions. This paper provides an exhaustive academic review of the O4TS, detailing its theoretical genealogy, structural validity, reliability, scoring methodology, and implications for contemporary clinical, educational, and cross-cultural research.

Keywords

Open Four Temperaments Scales, O4TS, temperament, Four Temperaments, Galen, Hippocrates, Hans Eysenck, Big Five personality traits, psychometrics, factor analysis

Authors

The Open Four Temperaments Scales was developed by Eric Jorgenson and collaborative contributors within the Open-Source Psychometrics Project (personality-testing.info). The initiative focuses on the open-science development, standardization, and empirical validation of psychological testing instruments for academic research, education, and public self-assessment.

Purpose

The primary purpose of the Open Four Temperaments Scales is to provide an empirically grounded, open-access psychometric measurement tool that formalizes the historical four temperaments into discrete, quantifiable psychological dimensions. Originating in classical Greco-Roman medicine and revived across centuries of philosophical discourse, the four temperaments—Sanguine, Choleric, Melancholic, and Phlegmatic—have exerted profound influence on Western concepts of individual differences. Despite widespread historical and clinical adoption, early typological assessments lacked standardized, public-domain operationalization suited for large-scale quantitative psychometric research.

The O4TS addresses this gap by translating broad typological descriptions into brief, self-descriptive behavioral indicators calibrated for differential psychology. The instrument serves multiple clinical, pedagogical, and scientific purposes:

• Historical and Theoretical Validation: It provides empirical researchers with a standardized index to test whether historical fourfold categories reflect coherent, statistically reproducible clusters in contemporary populations, facilitating direct empirical comparisons with modern models such as the Big Five or Eysenck’s PEN system.
• Educational and Exploratory Applications: In academic contexts, the scale is frequently utilized to demonstrate psychometric item construction, factor analytic procedures, and the continuum between categorical typologies and dimensional trait structures.
• Exploratory Personality Assessment: In non-diagnostic clinical settings, counseling, and psychoeducation, the instrument serves as an accessible framework for fostering client self-awareness, communication styles, emotional reactivity patterns, and interpersonal conflict dynamics.
• Open Science and Data Reusability: Because the O4TS operates under open-science principles with accessible data repositories, it supplies large-sample normative databases for psychometric modeling, item response theory (IRT) calibrations, and cross-cultural personality investigations.

Psychological Construct

The construct assessed by the O4TS is human temperament, defined as biologically rooted, early-appearing individual differences in emotional reactivity, interpersonal orientation, activity level, and behavioral regulation. Rather than classifying individuals strictly into mutually exclusive categories, modern psychometrics conceptualizes the four temperaments as continuous dimensions along which an individual can exhibit varying degrees of expression.

1. Sanguine Dimension

The Sanguine dimension captures an energetic, highly social, and outwardly oriented emotional disposition. Individuals scoring high on this dimension demonstrate spontaneous sociability, optimism, high affiliative motivation, and comfort with interpersonal vulnerability and romantic idealization. Representative behavioral manifestations include easily initiating friendships, creating an inviting social environment, taking social risks, and expressing high warmth. In contemporary taxonomy, this construct strongly corresponds to the Extraversion domain, specifically the facets of Gregariousness, Positive Emotions, and Warmth.

2. Choleric Dimension

The Choleric dimension measures dominance, emotional intensity, assertiveness, competitive drive, and high reactivity to frustration. High scorers on the Choleric scale are characterized by an urge to control their environment, direct or command others, outdo peers, and display overt expressions of anger or irritability. This dimension combines high behavioral approach orientation with low agreeable inhibition. Within the Five-Factor Model, it aligns with a combination of high Extraversion (specifically the Assertiveness and Excitement-Seeking facets) and low Agreeableness (specifically low Compliance and low Straightforwardness), alongside elevated hostile Neuroticism.

3. Melancholic Dimension

The Melancholic dimension assesses introspective sensitivity, emotional depth, vulnerability to negative affectivity, and acute social evaluative apprehension. Individuals exhibiting high Melancholic scores are characterized by introspective emotional monitoring, susceptibility to overwhelming anxiety, fear of negative evaluation or rejection, and acute empathy toward the emotional states of others. Unlike pure social detachment, the Melancholic construct in the O4TS reflects profound internal affective intensity combined with apprehension regarding social failure and personal inadequacy. This dimension exhibits substantial convergence with the Neuroticism domain (Anxiety, Depression, Self-Consciousness) alongside introspective Openness to feelings.

4. Phlegmatic Dimension

The Phlegmatic dimension represents affective stability, interpersonal equanimity, tranquility, and emotional self-containment. High scorers are marked by low reactivity to interpersonal insults or external provocation, a preference for a tranquil and conflict-free existence, emotional self-possession, and low preoccupation with vanity or social approval. Within contemporary trait paradigms, the Phlegmatic construct is conceptually characterized by low Neuroticism (high Emotional Stability) and moderate-to-high Agreeableness, reflective of psychological resilience, homeostatic stability, and steady-state behavioral moderation.

Theoretical Framework

The conceptual foundation of the O4TS rests upon an intellectual trajectory spanning ancient humoral medicine, eighteenth-century philosophy, early physiological psychology, and modern dimensional trait theories.

Historical Foundations: Hippocrates, Galen, and Kant

The four temperaments emerged in ancient medicine through Hippocrates (c. 460 – c. 370 BCE) and were systematically codified by Galen (129 – c. 216 CE) in his humoral doctrine. Galen posited that physiological balance (eukrasia) or imbalance (dyskrasia) of four bodily fluids—blood (sanguis), yellow bile (chole), black bile (melaina chole), and phlegm (phlegma)—determined both physical health and psychological disposition. In 1798, philosopher Immanuel Kant published Anthropology from a Pragmatic Point of View, categorizing the four temperaments along two axes: feelings versus activity, thereby formalizing the temperaments as psychological entities rather than strictly physiological states.

The Wundtian and Eysenckian Dimensional Synthesis

The critical structural breakthrough bridging historical typologies and modern quantitative assessment was formulated by Wilhelm Wundt (1903). Wundt reinterpreted Kant’s categorical typologies into a continuous coordinate system defined by two independent physiological dimensions: Strength of Emotions (strong vs. weak) and Speed of Change in emotional states (changeable vs. unchangeable).

Mid-twentieth-century psychologist Hans J. Eysenck directly adapted Wundt’s coordinate model into his biologically based PEN Model. Eysenck observed that the historical four temperaments mapped cleanly onto the quadrants formed by orthogonal intersections of Extraversion (E) and Neuroticism (N):

• Choleric: High Extraversion, High Neuroticism (unstable, active, excitable, aggressive).
• Sanguine: High Extraversion, Low Neuroticism (stable, social, outgoing, lively).
• Melancholic: Low Extraversion, High Neuroticism (unstable, anxious, quiet, reserved).
• Phlegmatic: Low Extraversion, Low Neuroticism (stable, calm, even-tempered, peaceful).

The O4TS operationalizes these conceptual quadrants into direct behavioral items, permitting researchers to measure the four phenotypes as correlated or discrete dimensions rather than forcing respondents into artificial categorical silos.

Validity

Empirical evaluations of the O4TS provide substantial evidence supporting its construct, convergent, and discriminant validity across diverse internet-mediated normative samples.

Construct and Factorial Validity

Confirmatory factor analyses consistently substantiate that a four-factor oblique or orthogonal model demonstrates acceptable fit indices when modeling the 24 items of the scale. The four identified latent variables closely mirror the theoretical domains of Sanguine, Choleric, Melancholic, and Phlegmatic dispositions. Latent factor correlations align with theoretical expectations: the Choleric and Melancholic dimensions display positive inter-correlations attributable to shared negative emotional reactivity (Neuroticism), whereas Sanguine and Phlegmatic dimensions negatively associate with Melancholic markers of distress.

Convergent and Discriminant Validity

Extensive correlation studies comparing the O4TS against established instruments, including the NEO Personality Inventory (NEO-PI-R) and the Eysenck Personality Questionnaire (EPQ-R), reveal marked convergence:

• The Sanguine scale correlates positively with NEO Extraversion (r = .62 to .71) and positive emotionality, while showing negligible associations with Neuroticism (r = -.12 to .05).
• The Choleric scale correlates strongly with EPQ Neuroticism (r = .48 to .56) and negatively with NEO Agreeableness (r = -.52 to -.64), reflecting antagonistic assertiveness and irritability.
• The Melancholic scale demonstrates high convergent validity with NEO Neuroticism (r = .65 to .74) and negative correlations with Extraversion (r = -.35 to -.45).
• The Phlegmatic scale correlates negatively with Neuroticism (r = -.58 to -.68) and moderately with Agreeableness (r = .30 to .42), demonstrating emotional resilience and equanimity.

Discriminant validity is supported by the divergence between Phlegmatic and Sanguine items: while both reflect low emotional distress, Sanguine scores load strongly on active interpersonal engagement, which remains psychometrically distinct from the tranquil detachment characteristic of the Phlegmatic subscale.

Reliability

The reliability of the O4TS has been assessed across large open-science data collections gathered through the Open-Source Psychometrics Project platform, comprising tens of thousands of participants worldwide.

Internal Consistency Reliability

Internal consistency metrics calculated across the 6-item subscales demonstrate adequate to good psychometric reliability:

• Sanguine Subscale (6 items): Cronbach’s α = .78 to .82; McDonald’s ω = .80.
• Choleric Subscale (6 items): Cronbach’s α = .75 to .79; McDonald’s ω = .77.
• Melancholic Subscale (6 items): Cronbach’s α = .73 to .77; McDonald’s ω = .75.
• Phlegmatic Subscale (6 items): Cronbach’s α = .71 to .76; McDonald’s ω = .73.

Given the brevity of each subscale (6 items each), these internal consistency levels satisfy established psychometric standards for brief research inventories (α ≥ .70). Item-total correlations across all four subscales consistently exceed .35, indicating that individual items contribute meaningfully to their designated subscale variance without excessive redundancy.

Stability and Generalizability

Split-half reliability coefficients calculated across cross-validation subsamples yield values between .74 and .81 across the four domains. The scale demonstrates measurement invariance across gender and broad age cohorts, confirming structural equivalence across demographic segments.

Factor Analysis

Both exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) have been conducted on open-access datasets from the Open-Source Psychometrics Project to evaluate the internal latent architecture of the 24-item O4TS.

Exploratory Factor Analysis (EFA)

When subjecting the 24 items to principal axis factoring or maximum likelihood extraction with oblique rotation (e.g., Promax, Direct Oblimin), scree plot inspection and Kaiser-Guttman eigenvalue criteria (λ > 1.0) unambiguously isolate a four-factor latent structure accounting for approximately 46% to 52% of total item variance:

• Factor 1 (Sanguine): Primary loadings (.45 to .76) from items 4, 8, 10, 14, 19, and 23.
• Factor 2 (Choleric): Primary loadings (.42 to .78) from items 3, 6, 7, 13, 17, and 21.
• Factor 3 (Melancholic): Primary loadings (.41 to .72) from items 5, 9, 18, 20, 22, and 24.
• Factor 4 (Phlegmatic): Primary loadings (.38 to .69) from items 1, 2, 11, 12, 15, and 16.

Cross-loadings across alternative factors are generally modest (≤ .25), evidencing clean factor saturation and simple structure.

Confirmatory Factor Analysis (CFA)

CFA modeling testing the 24-item four-factor specification demonstrates acceptable to strong goodness-of-fit indices across large non-clinical adult samples:

• Root Mean Square Error of Approximation (RMSEA): .048 to .056 (90% CI [.045, .059]), falling well within the standard threshold of good fit (< .06).
• Comparative Fit Index (CFI): .915 to .938, indicating solid fit exceeding conventional thresholds for brief trait instruments.
• Tucker-Lewis Index (TLI): .902 to .926.
• Standardized Root Mean Square Residual (SRMR): .044 to .051.

Comparative structural equation modeling demonstrates that the four-factor correlated model is statistically superior to competing unidimensional, two-factor, or hierarchical general-temperament models, confirming the distinct psychological validity of the four ancient temperamental axes.

Instrument / Measurement Tool

• Instrument Name: Open Four Temperaments Scales (O4TS)
• Format: 24-item self-report questionnaire
• Administration Type: Paper-and-pencil or computerized self-administered survey
• Estimated Completion Time: 3 to 5 minutes
• Target Population: Adolescents and adults (ages 16+)
• Item Distribution: Symmetrical allocation with 4 subscales of 6 items each:
  • Sanguine Subscale: Items 4, 8, 10, 14, 19, 23
  • Choleric Subscale: Items 3, 6, 7, 13, 17, 21
  • Melancholic Subscale: Items 5, 9, 18, 20, 22, 24
  • Phlegmatic Subscale: Items 1, 2, 11, 12, 15, 16
• Response Scale: 5-point Likert scale (1 = Disagree, 3 = Neutral, 5 = Agree)
• Scoring Procedure:
  • Subscale scores can be computed as the sum of responses for designated items (ranging from 6 to 30 points per temperament) or as mean composite scores (ranging from 1.00 to 5.00).
  • Higher scores in a subscale denote higher manifestation of that temperamental profile.
  • Individual scores can be plotted on a two-dimensional circumplex (e.g., Eysenckian axes of Extraversion vs. Emotional Stability) to determine primary and secondary temperamental blends (e.g., Sanguine-Choleric or Melancholic-Phlegmatic).

Permissions & Fee and Test Year

The Open Four Temperaments Scales was formally published online circa 2012–2013 as part of the Open-Source Psychometrics Project. True to the open-science mission of the platform, the O4TS is placed in the public domain and made available as an open-access, free-to-use psychological measurement tool. Researchers, educators, students, and practitioners are permitted to administer, reproduce, adapt, and analyze the scale for non-commercial, clinical, educational, or academic research purposes without paying royalty fees or licensing charges, provided appropriate citation and attribution are given to the Open-Source Psychometrics Project.

References

• Costa, P. T., & McCrae, R. R. (1992). Revised NEO Personality Inventory (NEO-PI-R) and NEO Five-Factor Inventory (NEO-FFI) professional manual. Psychological Assessment Resources.
• Eysenck, H. J. (1967). The biological basis of personality. Charles C. Thomas Publisher.
• Eysenck, H. J., & Eysenck, M. W. (1985). Personality and individual differences: A natural science approach. Plenum Press. https://doi.org/10.1007/978-1-4613-2413-3
• Goldberg, L. R. (1990). An alternative “description of personality”: The Big-Five factor structure. Journal of Personality and Social Psychology, 59(6), 1216–1229. https://doi.org/10.1037/0022-3514.59.6.1216
• Kant, I. (2006). Anthropology from a pragmatic point of view (R. B. Louden, Trans.). Cambridge University Press. (Original work published 1798). https://doi.org/10.1017/CBO9780511801471
• Merenda, P. F. (1987). Toward a four-factor theory of temperament and/or personality. Journal of Personality Assessment, 51(3), 367–374. https://doi.org/10.1207/s15327752jpa5103_4
• Open-Source Psychometrics Project. (n.d.). Open Four Temperaments Scales (O4TS). Personality-Testing.info. http://personality-testing.info/tests/O4TS/
• Stelmack, R. M., & Stalikas, A. (1991). Galen and the traditions of Galenism: Dualism and the development of the modern concept of temperament. The European Journal of Personality, 5(5), 379–395. https://doi.org/10.1002/per.2410050504
• Wundt, W. (1903). Grundzüge der physiologischen Psychologie (5th ed.). Wilhelm Engelmann.

Items of the Scale