Phrenology: History of a Pseudoscience

March 2000
by Steven Novella, MD

PhrenologyWhen first introduced in 1796, phrenology was the latest advancement in the field of neurology. It was widely accepted, even welcomed, by many practicing neurologists as a powerful diagnostic tool. Phrenologists were even on the winning side of an important scientific debate concerning a central concept of brain anatomy and function. As more scientific methods began to take hold within medicine, however, and the secrets of the brain began to yield to more careful investigation, phrenology became increasingly marginalized. By the end of the 19th century the last vestiges of phrenology were gone from scientific medicine and mainstream neurology, but not gone completely. Phrenology survives to this day as a classic pseudoscience, with dedicated adherents convinced of its efficacy.

The history of phrenology, and the story of its modern believers, is a classic one in the history of pseudoscience. To contemporary skeptics, the claims of phrenology sound no different than any wacky belief system. Believers claim to be able to read an individual’s personality, their strengths and weaknesses, hopes and desires, by examining the pattern of bumps on their skull. At first the idea sounds no different, and no less ridiculous, than treating liver disease by rubbing the foot, or diagnosing heart disease by the pattern of colors in the iris. It isn’t, but phrenology has a very different origin than reflexology or iridology.

To understand phrenology, we must begin with the central debate of neurological scientists of the 18th and 19th centuries. The question concerned the organization of the brain. One school believed that the brain was relatively homogenous, the entire brain worked together as a whole to produce all mental and motor functions. One particular function, therefore, such as humor, aggression, the ability to control the right hand, or recognize the scent of a rose, could not be localized to any piece of the brain. Trying to identify what any one part of the brain did, therefore, was useless.

The other school believed the exact opposite, that the brain was exquisitely compartmentalized. Every function that can be attributed to the brain could, they argued, be localized to a particular part of the brain, which was dedicated to that single function alone. To this latter school, understanding the brain would come through identifying which pieces were responsible for which functions. This hypothesis was initially proposed and championed in 1796 by Austrian physician Franz Joseph Gall (1758-1828), as part of his new theory of phrenology. (Gall, 1796)

But what does this have to do with bumps on the skull? To get there we have to add another principle. Gall and subsequent phrenologists argued that the parts of the brain which corresponded to functions that an individual used a great deal would hypertrophy (grow larger), while those functions which were neglected would atrophy (shrink). The brain, they argued, was like muscle – those muscles which are exercised frequently bulked up, while those that are not used remain small and even shrink. Their vision of the brain, therefore, was that it had a lumpy and bulbous surface, with a landscape unique to each individual based upon their particular set of intellectual and neurological strengths and weaknesses. They further argued that the skull overlying the lumpy parts of the brain would bulge out to accommodate the hypertrophied brain tissue underneath. Therefore, by measuring those bumps, one can infer which parts of the brain are enlarged and therefore which characteristics are dominant.

By the middle of the 19th century, phrenology parlors were widespread. Automated phrenology machines came later. The automated machines were composed of numerous spring-loaded probes. The device was placed over the head while the probes would extend to gently touch the scalp, thereby providing a measurement of the topography of the skull. The machine would then calculate the characteristics of the subject based upon this topography and produce an automated reading.

As it turns out, Gall and the phrenologists were correct when it came to the central debate of neurology of the time. The brain is compartmentalized, with each piece serving a specific function (Waxman, deGroot, 1995). The modern map of the brain, however, does not correlate to the classic map used by phrenologists. Theirs was more personality based, while the modern map is based on fundamental functions, such as the ability to perform mathematical calculations or interpret language.

All of the other assumptions of phrenology, however, are false. The brain is not, after all, a muscle. It does not hypertrophy or atrophy depending on use. The brain does change with use (a property called plasticity), but the changes occur on a microscopic level, and have to do with the strength and density of neural pathways, not gross bulk. Also, the brain is very jelly-like in consistency (Okazaki, 1989). The soft brain conforms to the shape of the skull, even in severe cases of cranial deformity due to disease or the bindings which are practiced in some cultures. The skull does not conform itself to the brain.

The scientific debate underlying phrenology was addressed over 100 years ago, and answered definitively. Modern neuroscience now far surpasses the preliminary knowledge on which the hypothesis of phrenology was based, and our contemporary perspective allows us to conclude with the highest degree of scientific certitude that two of the key assumptions of phrenology are incorrect, and in fact phrenology does not work. How then is it possible for belief in phrenology to persist? Frequent readers of this journal will likely suspect the answer.

Phrenology and Cold Reading

In the final analysis, practicing phrenologists were and still are using a method known as cold reading (see Cold Reading, Connecticut Skeptic, Spring 1997). Briefly, cold reading is the technique of making general statements about a target subject, statements which are likely to be somewhat true about almost any human being. In a dynamic cold reading, such as a psychic reading, subconscious feedback from the client is then used to make more and more specific statements, by pursuing the more accurate statements, the hits, and ignoring the misses. The results can seem very impressive, but the technique is actually quite simple once it is understood.

Cold reading can also be done, however, in a static fashion. In such cold readings, a limited set of pre-written statements concerning the subject are chosen according to some method. This can be done by making an astrological chart, reading a palm, or undergoing phrenological analysis. The pre-written statements, as with the opening statements of a dynamic cold reading, are designed to be vague and universal, so that anyone could see themselves to some degree in the statements. Readings such as “You like to be admired by others,” “At times you do not pay close enough attention to details,” or “You tend to feel more affection than you express to others,” are likely to strike a cord of recognition in all of us.

The most advanced expression of phrenology was the automated phrenology machine, called the psychograph, developed in 1931 by Henry C. Lavery. The psychograph automatically made 32 measurements of the subject’s skull, then produced a set of statements which were selected from 160 different possibilities, printed on small pieces of ticker tape and produced from the machine. I call this the “fortune cookie” style of cold reading. Phrenologists today also perform a more dynamic form of cold reading, by directly reading the bumps on a client’s skull with their hands, while actively interpreting the results, allowing for the process of feedback and refinement.

It is interesting to see how such elaborate lists of correlations (palm creases with personality traits, and iris flecks with diseases) come into being. Some appear to have been made up out of whole cloth. Others are based upon a small set of uncontrolled observations, which are then presented as scientific evidence. This was the case for phrenology. Gall, in fact, developed his hypothesis initially after measuring the contours of the skulls of several family members and friends. He believed he detected certain patterns of bumps and personality traits in these individuals, and developed his theory of phrenology from this preliminary data. Gall then went on to develop the elaborate phrenological chart from this information.

For a time, Gall’s work enjoyed prestige among the intellectual elite of Europe, who were just embracing the ideals of science and rationalism. His apparent systematic and scientific approach to the topic of human personality appealed to the rationalists of his time. As early as 1808, however, phrenology was already coming under scientific criticism. The Institute of France assembled a committee of savants, led by Cuvier, to investigate phrenology, and they concluded that it had no scientific basis. (Sabbatini, 1997) Over the ensuing years, scientists were unable to duplicate under more rigorous scientific conditions the phrenological charts made by Gall, and phrenology had failed a key test of true science, reproducibility. If the precepts of phrenology were correct, then any scientist in any lab could reproduce Galls chart through objective analysis of skull bumps and personality. It turns out, they couldn’t.

How, then, do believers defend their belief in phrenology, astrology, palmistry, iridology, or other such pseudoscience? Often the answer is simply, “I have seen it work.” They believe they have seen the method they employ work, and therefore the underlying principles must be true, no matter how much they appear to contradict established science. What true believers in such pseudosciences fail to appreciate is the basic skeptical principle that people are easily deceived, especially by themselves. The illusion of accuracy produced by cold reading often fools not only the client, but the reader as well, reinforced by each client who gushes over how accurate the readings were.

This principle is convincingly demonstrated by a classic tale told by psychologist and CSICOP fellow, Ray Hyman. As a youth he took up the practice of palmistry to make some extra money. He did not really believe in palm reading, but was amazed at the apparent accuracy of his readings, simply by following, cook book style, the formula in a standard handbook of palmistry. Before long he was convinced of palmistry’s fantastic power to penetrate the deepest secrets of his clients.

But Ray Hyman also had a scientific curiosity, an apparent rarity among palm readers. He decided to conduct a simple experiment to test the efficacy of palm reading. He began giving his clients the exact opposite reading as dictated by the handbook. To his surprise, his clients still claimed that his readings were amazingly accurate and were pleased with the results, to no less degree than when the “correct” readings were given. Dr. Hyman had discovered the power of cold reading which lay behind palmistry.

Another important factor in perpetuating belief in pseudosciences is a poor understanding of the process and principles of real science. In order to competently tell the two apart, one must be reasonably schooled in the various principles of both science and skepticism, a schooling which is conspicuously lacking in our society.

Modern Phrenology

Although clearly dead as a science by the end of the 19th century, phrenology survived into the 20th century, and even up to the present time, in various forms.
In the late 19th and early 20th centuries, the concepts of phrenology became associated with pseudoscientific ideas in the areas of criminology and evolution that were popular at the time. Craniology and Anthropometry were attempts at identifying evolutionary advancement and criminal tendency according to physical measurements of the skull and face. Of course, these measurements were used to verify pre-existing social prejudices. They were also adopted by the Nazi’s in their attempt to scientifically prove Arian racial superiority. It is perhaps this historical association between Nazi racism and attempts at measuring the intellectual capacity of people through physical morphology that pseudosciences like phrenology fell out of favor, even among the fringe.

Another modern manifestation of phrenology was originated by a Belgian by the name of Paul Bouts, who combined phrenology with typology (character analysis through body morphology) and graphology (character analysis through handwriting examination). He called his three-in-one pseudoscience Psychognomy, and advocated its usefulness until his death last year.

The most recent defense of phrenology I could find is a website published on 5/1/1998 by Peter Van den Bossche called “The Loose Foundations of Criticism against Phrenology.” (Van den Bossche, 1998) In a section labeled “Why Criticism is Wrong, Van den Bossche states:

“It would be an absurdity to reject Phrenology as such, without first assessing the value of the science, as is unfortunately too often done today. Extensive experimental verification of the Phrenological localizations have proven their practical value. The Phrenological analysis of personality remains of incomparable value to assess the character.”

As this example shows, criticisms of phrenology are dismissed as a-priori and arguments from authority. The actual scientific criticisms of phrenology, as outlined in this article, are not addressed or even acknowledged. Further, the claim of “extensive experimental verification” is not referenced, and is therefore unsubstantiated hearsay. In fact, there are no double-blinded verifications of phrenological localizations. Phrenology was rejected after scientists failed to replicate Gall’s claims, and 200 years of subsequent neuroscience has shown phrenology to be false. Modern phrenologists, however, make no accounting of the advances in neuroscience.


Today phrenology is a marginalized curiosity, and therefore has little impact upon our culture and society, which is appropriate given the poor scientific value of its ideas. The story of its origination as a scientific hypothesis (which was partly correct), eventual scientific rejection, and then evolution through various pseudoscientific permutations is a fascinating one, however, which still harbors lessons for the modern skeptic.


1) Gall, FJ, The Anatomy and Physiology of the Nervous System in General, and of the Brain in Particular. 1796.
2) Sabbatini, RME, Phrenology: the History of Brain Localization. 1997 (
3) Van den Bossche, Peter, The Loose Foundations of Criticism against Phrenology. 1998 (
4) Waxman, SG, deGroot J, Correlative Neuroanatomy. Appleton and Lange 1995, pp. 145-149
5) Okazaki H, Fundamental of Neuropathology. Igaku-Shoin, 1989.