What is phrenology?
Phrenology, created by Franz Joseph Gall in the early nineteenth century, held that character and inclinations, criminal ones included, sit in areas of the brain that can be read from the bumps of the skull. It is a pseudoscience, but it influenced nineteenth-century criminology and anticipated the idea of localising brain functions.
In the early 19th century, many people believed that character, intelligence and even the tendency toward crime could be read in the shape of the skull. By feeling the bumps and hollows of a head, an expert claimed to diagnose whether you had a developed “organ of destructiveness” or a prominent “organ of theft”. Phrenology was one of the most influential pseudosciences of its age, and one of the most dangerous, because it turned prejudice against physical appearance into “science” and planted an idea we still drag along: that evil has a recognizable shape.
Criminological phrenology at a glance
- Author
- Franz Joseph Gall
- Era
- Late 18th and 19th centuries
- Family
- Biological (pseudoscience)
- Idea
- Criminality can be read in the bumps of the skull
Skull bumps → cerebral “organs” → character and tendency toward crime (false)// OriginGall and the science of bumps
It was formulated by the German physician Franz Joseph Gall in the late 18th century. His starting point was not absurd: he believed, correctly, that different mental functions reside in different areas of the brain. From there he leapt to a false conclusion: that these faculties made cerebral “organs” grow that bulged the skull on the outside. Gall went so far as to identify an “organ of the tendency toward murder”, especially developed, he said, in criminals. Phrenology spread across Europe and America as a scientific fad and was used to select employees, justify social hierarchies and, above all, single out criminals by the shape of their head.
It is a first cousin of physiognomy (reading character in the face) and the direct grandmother of Lombroso's born criminal. They all share one false thesis: that the criminal is recognizable by their physique. There is no correlation between the shape of the skull or the ugliness of a face and the tendency toward crime, and phrenology was refuted almost two centuries ago. Its underlying idea, that the criminal can be spotted just by looking, has proven far harder to kill.
The verdict on phrenology
No skull holds a murder organ, and no face reveals a criminal.
Prejudice disguised as measurement
The danger of phrenology lies in how it is false: it takes a preexisting prejudice (that people of strange, deformed or “ugly” appearance are suspicious) and clothes it in instruments, measurements and scientific language, making it respectable. Stephen Jay Gould documented this in The Mismeasure of Man: phrenologists and craniometrists “measured” skulls and always confirmed the hierarchies they already believed, with their own group on top and the poor, foreigners and oppressed races below, as naturally inferior and criminal. The measurement discovered nothing; it disguised prejudice as data.
The (false) logic of phrenology, step by step
- 1Partial premiseDifferent mental functions reside in different areas of the brain (this part is true)
- 2False leapGall claims that each faculty makes an “organ” grow that bulges the skull on the outside
- 3Measuring the prejudiceFeeling the bumps “measures” personality… and always confirms the hierarchies the expert already believed
- 4Sentencing by the physiqueThe criminal is “detected” by the shape of their head, giving scientific cover to the stereotype
Refuted almost two centuries ago: there is no correlation between the shape of the skull and behavior. It only disguised prejudice as data.
// In fictionFaces the pseudoscience would condemn
el Jorobado, the hunchback of Notre Dame, has the physique any phrenologist would have marked as monstrous and dangerous, and he is one of the kindest and most loyal beings in literature, scorned by a society that judges by shape. Sloth, in The Goonies, is deformed, enormous and kept chained like a monster by his own criminal family, and he turns out to be the noblest of them all: the “monster” who saves the children. Prince Adam, in Beauty and the Beast, turns the objection into a fairy tale: his appearance is terrifying, and the whole story is about learning to see beyond the physique.
The Toxic Avenger, the Toxic Avenger, takes it to parody: a deformed and repulsive monster who is literally the hero and protects the weak from the real villains, handsome and “normal”. Shrek makes it a pop icon: an ogre everyone fears for his physique turns out to be kind, while the villain of the story, the tiny, tidy Lord Farquaad, has the “respectable” look. None of them proves anything; they illustrate what the data already established, that appearance does not predict character.
"Monsters" phrenology would have condemned by their face. Tap to open their case file.
// The phrenology of the 21st centuryWhen AI promises to detect criminals by their face
Phrenology did not die in the 19th century: it resurfaces every time a new technology promises to read criminality in the physique. In 2016, a study claimed that an artificial intelligence could tell “criminal faces” from photographs alone. The scientific community demolished it: the algorithm detected biases in the data, not criminality. The photos of “criminals” were police mugshots, with different expressions and framing, and the system learned to recognize that. It is Gall's error in new clothes: a prejudice (who “looks” criminal) disguised as an objective measurement. And these systems are already deployed in predictive policing, police facial recognition and border control, with an aura of mathematical neutrality that makes them believable.
// The crackWhy dismantling a dead idea matters
The temptation is to treat phrenology as a harmless historical curiosity. That would be a serious oversight: phrenology and its offshoots did enormous harm, giving “scientific” cover to racism, slavery, colonialism and eugenics, and its logic is still alive in the everyday prejudice that associates certain features, skin colors or appearances with dangerousness, the same one that makes the police “see” a young person as suspicious because of their face or their clothes.
The only honest “reading” that science permits of the brain and the body is probabilistic, partial and never deterministic, as responsible neurocriminology and genetics remind us. Between that neuroscience and phrenology lies the distance between astronomy and astrology: one measures with humility what it can; the other projects prejudice and calls it destiny.
The pseudoscience that sowed scientific racism
From Gall to Lombroso and from Lombroso to algorithms, the idea of reading evil in the physique has changed instruments without changing its error. Along the way it served as intellectual scaffolding for scientific racism and eugenics.
- 1796Gall begins to expound his “organology”: the mind read in the skull.
- 1810-1819He publishes, in four volumes (the first two with Spurzheim), Anatomie et physiologie du système nerveux, the foundation of phrenology.
- 1876Lombroso inherits the idea and extends it to the whole body with the “born criminal”.
- 2016An AI claims to “detect criminals by their face”: phrenology in new clothes, demolished by bias in the data.
Lights and shadows
- It got one real intuition right: different mental functions are localized in different areas of the brain (it anticipated neuroscience).
- It popularized the idea that the mind has a studiable biological basis, not merely a spiritual one.
- It stimulated interest in the brain and was a first (clumsy) attempt to study crime “scientifically”.
- Its failure taught a valuable methodological lesson: distrust any “science” that always confirms the prejudices of whoever practices it.
- It is false: there is no correlation whatsoever between the shape of the skull (or the face) and the tendency toward crime.
- It disguised a prior prejudice as an objective measurement: that a strange or “ugly” appearance is suspicious.
- It gave “scientific” cover to racism, slavery and eugenics, with atrocious consequences.
- Its logic is still alive in biased facial AI and in the everyday prejudice that associates certain features with dangerousness.
// Why it mattersEvil has no face
Read in reverse, the lesson is that evil has no face. The great criminals of history almost always looked ordinary (the genocidal man with a kindly face, the elegant swindler, the murderer who “seemed normal”), while countless people of “monstrous” or simply different appearance were persecuted for a physique that said nothing about their character. Every time something or someone promises to detect the criminal by their appearance, they will be selling, with new technology, the same old lie.
Three key takeaways
- Phrenology (Gall) claimed to read criminality in the bumps of the skull. Cousin of physiognomy and grandmother of Lombroso's born criminal, it shares with them the false thesis that "evil can be seen".
- Its danger lies in how it is false: it disguises a prejudice (a strange appearance is suspicious) as scientific measurement. As Gould showed, it "measured" skulls and always confirmed the hierarchies it already believed.
- It did not die: it resurfaces in the AI that promises to detect "criminal faces" and only detects biases in the data. It served as scaffolding for scientific racism and eugenics.
Sources · further reading
- Gould, S. J. (1981). The Mismeasure of Man. Norton.
- Gall, F. J. & Spurzheim, J. G. (1810-1819). Anatomie et physiologie du système nerveux en général, et du cerveau en particulier (4 vols.). Schoell.
- Wu, X. & Zhang, X. (2016). “Automated Inference on Criminality Using Face Images” — and the critical replies (Y. LeCun, Aggarwal et al.).
- Rafter, N. (2008). The Criminal Brain. NYU Press.
// Test the theoryWhich of these villains does KRIMINIS analyse with Criminological Phrenology?
Theory questionsFrequently asked questions
What is phrenology?
Phrenology, created by Franz Joseph Gall in the early nineteenth century, held that character and inclinations, criminal ones included, sit in areas of the brain that can be read from the bumps of the skull. It is a pseudoscience, but it influenced nineteenth-century criminology and anticipated the idea of localising brain functions.
Who formulated phrenology, and when?
German physician Franz Joseph Gall, who began presenting his "organology" in 1796. He systematised it in "Anatomie et physiologie du système nerveux en général, et du cerveau en particulier", published in four volumes between 1810 and 1819, the first two co-authored with Johann Spurzheim.
Does phrenology have any validity today?
No: it is a refuted pseudoscience. It was right only in its intuition that different mental functions sit in different areas of the brain; everything else was false. It also did enormous harm, giving "scientific" cover to racism, slavery, colonialism and eugenics. Current science allows only probabilistic, partial and never deterministic readings of the brain.
How is phrenology related to Lombroso and to AI that claims to spot criminals by their faces?
It is their direct ancestor. Cesare Lombroso inherited the idea in 1876 and extended it to the whole body with his "born criminal". In 2016 a study by Wu and Zhang claimed to infer criminality from facial photos using artificial intelligence, and critical replies demolished it for the bias in its data: the same phrenological logic in new clothes.