Phrenology was a pseudoscience that defended that the shape of the skull gave information about the faculties and mental features of people. This movement was popularised in the 18th century by the physician Franz Gall and had a large number of followers, although it lost relevance after a few decades.

In this article we will describe the history of Phrenology, the basic postulates of this discipline and the conception of the brain that the disciples of Gall had. Finally, we will talk about the legacy of Phrenology in modern neuroanatomy.

History of Phrenology

The phrenological hypotheses did not arise in a vacuum, but were derived from previously existing conceptions. In particular, during the 18th century physiognomy, which proposed that people’s physical appearance could be used as a basis for analysing their psychology, enjoyed some popularity, and Charles Bonnet influenced brain localisation.

The German doctor Franz Joseph Gall (1758-1828) began to give lectures on Phrenology in 1796. It was his collaborator Johann Gaspar Spurzheim, also a key figure, who spread the word “Phrenology”, which Gall disavowed since he saw himself mainly as a physiologist and neuroanatomist.

Like mesmerism, phrenology spread as a probable scientific truth among the lower and middle classes of 18th century Europe, which were very open to advances in different fields because of the influence of the French Revolution and the Enlightenment. Edinburgh became the nucleus of Phrenology , and there the first Phrenological Society was founded.

By the 1840s, barely 40 years after its emergence, the hypotheses of Phrenology had been discredited by the scientific community. However, interest in these practices spread to America and Africa with European colonization, and in many places they have re-emerged at specific times, especially as a tool of racial domination.

Basic postulates of Franz Joseph Gall

Gall published in 1819 his key work: “Anatomy and physiology of the nervous system in general, and of the brain in particular, with observations on the possibility of recognizing many intellectual and moral dispositions of man and animals by the configuration of their heads”.

In this text Gall described the six basic postulates of phrenology .

1. The brain is the organ of the mind

For phrenologists the mind was situated in the brain; today this idea, which was also not new in Gall’s time, enjoys great popularity. This approach was opposed to the concept of mind as a manifestation of the soul, more widespread in the 18th century than today.

2. The mind is composed of faculties

The mind is not a unitary entity, but is composed of multiple faculties. In Phrenology the concept “faculty” refers to the different specializations or tendencies of the mind , such as ambition, perseverance or benevolence. Later on we will list the faculties described by Gall.

3. Each faculty is located in an organ

Gall considered that, since mental faculties are different and unique, they must necessarily be located in “organs” separate from the brain. This postulate makes phrenology a antecedent of the localizationist theories on the functions of the central nervous system.

4. The size of an organ indicates its power

The relative size of each organ compared to the rest of the brain can be taken as a sign of the development of a given faculty, according to phrenology. Likewise, an organ can be larger in one of the brain hemispheres than in the other.

5. The organs determine the shape of the skull

Gall stated that during child development the bones of the skull adopt their shape according to the size of the brain organs . These structural idiosyncrasies, and the psychological ones derived from them, are maintained for the rest of the life once the growth of the brain has finished.

6. The surface of the skull reveals the mind

This is probably the most famous principle of phrenology : since the development of the organs (and therefore of the faculties) influences the shape of the skull, the analysis of its surface allows to determine the personality and the other mental features of a person.

Gall and most phrenologists examined the skull with their fingers and palms for peculiarities, such as clefts or overdeveloped regions. They also used tape measures and occasionally a special calibrator called a “craniometer”.

Phrenological organs and mental faculties

Gall proposed 27 faculties associated with specific brain organs . Although his proposal is the best known in this field, there has never been a real consensus among phrenologists regarding the number and characteristics of these regions.

  • 1. Propagation (reproductive) impulse
  • 2. Parental love
  • 3. Friendly attachment and fidelity
  • 4. Value and self-protection
  • 5. Murder and Carnivorousness
  • 6. Cunning
  • 7. Theft and sense of ownership
  • 8. Pride, arrogance and love of authority
  • 9. Ambition and vanity
  • 10. Prudence
  • 11. Aptitude for learning and education
  • 12. Sense of location
  • 13. Remembrance of people
  • 14. Verbal sense and memory
  • 15. Language school, talent for words
  • 16. Preference for color
  • 17. Sense for Sounds and Musical Talent
  • 18. Numerical and temporal sense
  • 19. Mechanical aptitude
  • 20. Comparative acuity
  • 21. Metaphysical acuity
  • 22. Ingenuity, sense of causality and inference
  • 23. Poetic talent
  • 24. Benevolence, compassion, and moral sense
  • 25. Mimicry, ability to imitate
  • 26. Theosophy, religious sentiment
  • 27. Perseverance and firmness

Phrenology Today

Although his methods were wrong, some of Gall’s claims have been confirmed over time and scientific progress. Thus, it is known that indeed there are relevant brain structures for certain functions , and that some of them develop with the use, as it happens with the hippocampus, involved in memory.

However, the phrenological approaches were very reductionist and rigid compared to what is now known about the distribution of brain activity around regions and pathways. Likewise, the “organs” identified by Gall do not correspond to the faculties to which he associated them .

The exception is the region to which he attributed the faculty for language and verbal memory, which is located near the areas of Broca and Wernicke. These structures, located in the frontal and temporal lobes respectively, have been related to language comprehension and production.

The contributions of Phrenology and other localizationist positions on brain faculties have lost relevance today, but have allowed the extension of scientific knowledge. The brain areas described by Korbinian Brodmann are especially well known , which can be considered a more serious version of Gall’s proposal.