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Psychology and personality

The four temperaments: origin and what science says

Few ideas in psychology have lived as long as the four temperaments. The vocabulary (sanguine, choleric, melancholic, phlegmatic) is over two thousand years old and still shows up in magazines, self-help books and online quizzes. The question worth asking is what is actually left of that tradition. The answer has two parts. The original explanation, that the body contains four fluids whose balance defines health and character, fell together with humoral medicine. But the underlying intuition, that people are born with stable styles of reacting to the world, survived and became a respected research field. This guide walks through the history, shows where current science agrees and disagrees, and points to the [Four Temperaments Test](quiz:quiz-temperamento) as a light way to explore the classic model, with the warning that it is a self-reflection game, not a clinical instrument.

J-Kit10 min readIntermediate
  • Temperaments
  • Personality
  • History of medicine
  • Big Five

Key takeaways

  • The four humors (blood, phlegm, yellow bile, black bile) come from the Hippocratic treatise On the Nature of Man, from the fifth century BCE; humoral medicine was abandoned.
  • The idea of temperament survived: modern research shows stable differences from childhood, partly hereditary (average heritability of about 0.40 for personality).
  • Four boxes do not describe people: science uses continuous dimensions (extraversion, neuroticism and the rest of the Big Five), and the four types resemble the quadrants of two of them.
  • The temperament quiz is a historical model for self-reflection, not a diagnosis.

From humors to temperaments

The starting point is the Hippocratic treatise On the Nature of Man. The researcher William Adams, in a 2024 article in Greek, Roman, and Byzantine Studies, describes it as the fifth-century BCE text that offers a true humoral theory, with components inside the body: bile, phlegm, black bile and blood. Health, in this view, is balance among the four; disease is imbalance. The word "temperament" comes from this vocabulary: according to Serge Erlinger, in a history of bile research, it derives from the Latin temperare, "to mix", a proportioned mixture of qualities.

The four humors, their qualities and the associated temperament
HumorQualitiesElementTemperament
BloodWarm and moistAirSanguine
Yellow bileWarm and dryFireCholeric
Black bileCold and dryEarthMelancholic
PhlegmCold and moistWaterPhlegmatic

The qualities and elements in the table follow the summary in Erlinger's history of bile. The step that turns medicine into a typology of character is attributed to Galen. The open textbook OpenStax Psychology 2e sums it up this way: Galen built on Hippocrates, suggesting that humor imbalances would explain both disease and personality differences, and that each person would exhibit one of four temperaments, each tied to a set of traits. The choleric would be passionate and bold; the phlegmatic, calm and thoughtful.

  1. 5th century BCEOn the Nature of Man

    The Hippocratic treatise presents a humoral theory based on blood, phlegm, yellow bile and black bile.

  2. Roman eraGalen and the temperaments

    Galen uses humoral theory to explain differences in character too, and each humor gets a psychological profile.

  3. 1628Harvey and the circulation of blood

    According to a 2024 historical review, the discovery of circulation destroyed the basis of the humoral theory.

  4. 18th and 19th centuriesThe typology survives without the fluids

    Without the physiology, the four types continue as character description. Wundt reorganizes them along two emotion axes.

  5. 1988Kagan and biological shyness

    A longitudinal study in Science links childhood behavioral inhibition to physiological differences.

What survived of humoral theory

As medicine, nothing. A 2024 historical review of cancer theories recalls that Hippocrates, Aristotle and Galen interpreted cancer as an excess of black bile and that Harvey's discovery of blood circulation in 1628 destroyed the basis of humoral theory. No fluid "makes" someone sanguine or melancholic. What remained was the descriptive map: four character portraits that are still easy to recognize.

The review by Stelmack and Stalikas, published in 1991 in Personality and Individual Differences under the title Galen and the humour theory of temperament90111-N), follows the trail. Per its abstract, Galen used humoral theory to account for differences in character but made few characterological observations of his own; the descriptive typology that took shape in the 18th and 19th centuries closely resembles the dimensions of extraversion and neuroticism. That is the bridge modern psychology crosses: the four types as quadrants of two axes.

Wundt: strong or weak emotion, changeable or unchangeable

  • First axis: strong emotions (melancholic and choleric) against weak (phlegmatic and sanguine).
  • Second axis: changeable temperaments (choleric and sanguine) against unchangeable ones (melancholic and phlegmatic).
  • Source: OpenStax Psychology 2e textbook.

Usual modern reading: extraversion × emotional stability

  • Sanguine: extraverted and emotionally stable.
  • Choleric: extraverted and emotionally unstable.
  • Phlegmatic: introverted and stable. Melancholic: introverted and unstable.
  • It is an approximate correspondence, and the continuous scale matters more than the quadrant.

Kagan and modern temperament research

Modern research treats temperament as early, stable differences in reactivity and self-regulation, observable in childhood. The best-known work is by the psychologist Jerome Kagan and colleagues. In the 1988 paper Biological bases of childhood shyness, published in Science, two longitudinal studies followed 2-year-olds who were extreme in either restraint or spontaneity in unfamiliar situations. By age 7, a majority of the restrained group were quiet and avoided unfamiliar children and adults, while a majority of the spontaneous group were talkative and interactive. Peripheral physiological differences suggested that inherited variation in the arousal threshold of certain limbic sites might contribute to shyness.

Later studies went further, with caution. In a 2003 functional MRI study, Schwartz and colleagues compared adults classified in their second year of life as inhibited or uninhibited, and the inhibited ones showed a larger amygdala response to novel than to familiar faces. The review by Fox and colleagues (2005) describes behavioral inhibition as a style of reacting to novel situations with physiological parallels to fear systems, and discusses that stable inhibition may be a risk factor for anxiety in older children. Risk is not destiny: the same review discusses the role of caregiving and cognitive processes.

Behavioral inhibition
The tendency of some children to react with withdrawal and caution to new people and situations. It is the central construct of Kagan's line of work.
Temperament
Early individual differences in emotional reactivity and self-regulation, partly hereditary, which serve as a base for adult personality.
Heritability
The fraction of variation among people in a population attributable to genetic differences. It does not say how much of an individual's personality is "genetic".

The Big Five, genetics and the limits of four types

The dominant model of adult personality is the Big Five: extraversion, agreeableness, conscientiousness, neuroticism and openness. On the weight of genes, the meta-analysis by Vukasović and Bratko (2015), in Psychological Bulletin, pooled 62 independent effect sizes from over 100,000 participants and found an average heritability of 0.40: about 40% of personality differences among people are associated with genetic differences, and the other 60% with environment. Twin studies gave higher estimates (0.47) than family and adoption studies (0.22), a reminder that the number depends on the method.

0.40average heritability of personality (2015 meta-analysis)
0.47 vs 0.22twin studies against family and adoption studies
674youths followed from age 10 to 26 in a 2026 study of temperament and the Big Five

The link between childhood temperament and adult personality was tested longitudinally by Ringwald and colleagues, in a 2026 study of 674 Mexican-origin youth assessed on temperament traits (negative emotionality, surgency, affiliation and effortful control) from ages 10 to 16 and on Big Five traits from ages 14 to 26. They found continuity between childhood and adolescent temperament and personality at 26, with the strongest associations between conceptually similar traits, and effortful control predicting all Big Five traits except extraversion. Over the period, the youths increased in effortful control and conscientiousness and decreased in negative emotionality and neuroticism. In other words: temperament is a starting point, and maturation moves it.

The four classic temperaments and the modern dimensions that come closest
ClassicClosest modern dimensionWhat science adds
SanguineHigh extraversion, low neuroticismA continuum, not a box; varies with context and age.
CholericHigh extraversion, high neuroticismThe modern model adds conscientiousness and agreeableness, which the four types do not describe.
MelancholicLow extraversion, high neuroticismChildhood behavioral inhibition is a related research topic, but it is a tendency, not destiny.
PhlegmaticLow extraversion, low neuroticismCalm is not a lack of openness or ambition; those dimensions fall outside the model.

The limitations are clear. The four types ignore three of the five Big Five dimensions (agreeableness, conscientiousness, openness), treat a continuum as a category and have no validation as a measurement instrument. The tradition is worth keeping as cultural language and a gateway, not as personality science.

How to use the temperament quiz sensibly

The Four Temperaments Test measures how much you identify with each of the four classic portraits and returns a profile among 11 possible results: the four "pure" types, the six combinations of two temperaments and a balanced profile, with a trait chart. Choosing dimensions instead of a single box follows, in practice, what science recommends: nobody is 100% one temperament. For a reading with empirical backing, the Big Five Test covers the five dimensions that research uses.

  • Read the result as a hypothesis about your habits, not a fixed label.
  • Notice how much the result depends on your mood that day; traits are stable, answers to a quiz less so.
  • Look for what the model leaves out: conscientiousness, openness and agreeableness.
  • Distrust any description that fits everyone: that is the Barnum effect.

Frequently asked questions

Who invented the four temperaments?
The basis is the four-humors theory of the Hippocratic treatise On the Nature of Man, from the fifth century BCE. The idea that each humor corresponds to a temperament is attributed to Galen, who used the theory to explain personality differences as well.
Do the four temperaments have a scientific basis?
The original explanation, the body fluids, no. The idea that there are stable, partly hereditary differences in temperament has strong support, though, and the four types resemble the quadrants of extraversion and neuroticism. The modern model is dimensional (the Big Five), not four boxes.
What did Kagan find about temperament?
In a 1988 study in Science, 2-year-olds who were extreme in restraint toward the unfamiliar tended, by age 7, to be quiet and avoid new people, while spontaneous ones tended to be talkative. The physiological differences suggested influence from inherited variation in the arousal threshold of limbic regions. It is a statistical tendency, not destiny.
How much of personality is genetic?
A 2015 meta-analysis in Psychological Bulletin found an average heritability of 0.40, meaning about 40% of the variation among people is associated with genetic differences and 60% with environment. The figure is for populations, not individuals, and changes with method (twins 0.47; family and adoption 0.22).
Does my temperament change with age?
On average, yes, slowly. In a 2026 longitudinal study, participants increased in effortful control and conscientiousness and decreased in negative emotionality and neuroticism between childhood and early adulthood, while keeping their relative position among peers.

The four temperaments are a legacy of humoral medicine: the fluid explanation fell, but the vocabulary stayed. Modern research confirms that stable, partly hereditary differences in temperament exist from childhood (average personality heritability of about 0.40), and that the four types resemble quadrants of extraversion and neuroticism. But science works with continuous dimensions, not four boxes. Use the quiz as a self-reflection game about a historical model, and the Big Five when you want something with empirical backing.

Sources & references

  1. Adams, W. H. (2024). An Early Conception of Inflammation in the Hippocratic Treatise Diseases I. Greek, Roman, and Byzantine Studies 64
  2. Erlinger, S. (2022). A history of research into the physiology of bile, from Hippocrates to molecular medicine. Clinical Liver Disease
  3. OpenStax, Psychology 2e: What Is Personality (Galen, Wundt)
  4. El Nachef et al. (2024). A narrative history of theories of carcinogenesis. Cancers (Harvey, 1628)
  5. Stelmack, R. M. & Stalikas, A. (1991). Galen and the humour theory of temperament. Personality and Individual Differences 12, 255-263
  6. Kagan, J., Reznick, J. S. & Snidman, N. (1988). Biological bases of childhood shyness. Science 240, 167-171
  7. Schwartz, C. E. et al. (2003). Inhibited and uninhibited infants "grown up": adult amygdalar response to novelty. Science 300, 1952-1953
  8. Fox, N. A. et al. (2005). Behavioral inhibition: linking biology and behavior within a developmental framework. Annual Review of Psychology 56, 235-262
  9. Vukasović, T. & Bratko, D. (2015). Heritability of personality: a meta-analysis of behavior genetic studies. Psychological Bulletin 141, 769-785
  10. Ringwald, W. R. et al. (2026). Linking temperament and personality traits from late childhood to adulthood. Journal of Personality and Social Psychology

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