Phrenology: measuring the skull to study the mind

Phrenology was a pseudoscience that argued that the shape of the skull gave information about mental faculties and traits of people. This movement was popularized in the 18th century by the doctor 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 Gall's disciples had. Finally, we will talk about the legacy of phrenology in modern neuroanatomy.

• Related article: "History of Psychology: main authors and theories"

History of phrenology

Phrenological hypotheses did not arise in a vacuum, but were derived from conceptions that previously existed. In particular, physiognomy, which proposed that the physical appearance of people could be used as a basis for analyzing their psychology, and Charles Bonnet influenced localizationism cerebral.

The German physician Franz Joseph Gall (1758-1828) he began lecturing 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 primarily as a physiologist and neuroanatomist.

Like mesmerism, phrenology spread as a probable scientific truth among the lower and middle classes of early Europe. 18th century, very open to advances in different fields due to the influence of the French Revolution and the Enlightenment. Edinburgh became the core of phrenology, and there the first phrenological society was founded.

By the 1840s, just 40 years after their emergence, the phrenology hypotheses 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 resurfaced at specific moments, especially as a tool of racial domination.

• Related article: "Morphopsychology: your facial features... Do they indicate your personality?"

Basic Postulates of Franz Joseph Gall

Gall published his key work in 1819: "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 not new in Gall's time, is very popular. This approach was opposed to the conception of mind as a manifestation of the soul, more widespread in the 18th century than today.

2. The mind is made up 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 we will make a list of the faculties described by Gall.

3. Each faculty is located in an organ

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

4. The size of an organ indicates its power

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

5. Organs determine the shape of the skull

Gall claimed that during child development the bones of the skull take their shape according to the size of the brain organs. These structural idiosyncrasies, and the psychological ones that derive from them, persist for the rest of life after brain growth 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 rest of a person's mental traits.

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

Phrenological organs and mental faculties

Gall proposed 27 powers associated with brain organs concrete. Although his proposal is the best known in this field, there was never a true consensus among phrenologists regarding the number and characteristics of these regions.

• 1. Propagation impulse (reproductive)
• 2. Parental love
• 3. Friendly attachment and fidelity
• 4. Courage and self-protection
• 5. Murder and carnivorism
• 6. Cunning
• 7. Theft and sense of property
• 8. Pride, arrogance and love of authority
• 9. Ambition and vanity
• 10. Prudence
• 11. Fitness for learning and education
• 12. Sense of location
• 13. Memory of people
• 14. Verbal sense and memory
• 15. Linguistic faculty, talent for words
• 16. Color preference
• 17. Sense for sounds and musical talent
• 18. Numerical and temporal sense
• 19. Mechanical fitness
• 20. Comparative acuity
• 21. Metaphysical acuity
• 22. Ingenuity, sense of causality and inference
• 23. Poetic talent
• 24. Benevolence, compassion and moral sense
• 25. Mimic, 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 with the passage of time and scientific progress. Thus, it is known that indeed there are brain structures relevant to certain functions, and that some of them develop with use, as happens with hippocampus, involved in the memory.

However, phrenological approaches were very reductionist and rigid compared to what currently known about the distribution of brain activity around regions and tracks. In addition, 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 Broca and Wernicke areas. These structures, located in the frontal lobes Y temporary respectively, they have been related to language comprehension and production.

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