Jun 23 2009

Phrenology – History of a Science and Pseudoscience

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Comments: 26

When 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 early 20th 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). (Gall, 1796)

Gall’s notions were first explored further by neurophysiologist Pierre Flourens, who in the 1800s followed up on Gall’s work with a series of experiments on rabbits and pigeons. He found that coordination localized to the cerebellum, while basic functions like respirations localized to the brainstem. However, he could not localize higher cortical functions, like memory, and so concluded that while primitive neurological functions did localize to one part of the brain, the higher cognitive functions were diffuse in the cerebral hemispheres.

Flourens was wrong, and this probably has something to do with the fact that he was studying rabbits and pigeons, making it difficult to assess cognitive function.

Pierre Paul Broca then took this research further, using clinical evaluations of humans to see if specific mental functions could be localized to specific brain tissue, and he was very successful in his research. One part of the cortex in the dominant frontal lobe is now called Broca’s area in his honor – this brain structure serves the specific function of translating language into the motor function of speech. Damage to this area results in what is called a Broca’s aphasia.

After Broca’s contributions to neuroscience the scientific community had largely settled on the compartmentalist view of the brain. The phrenologists belonged to this school from the beginning – they were compartmentalists. But what does this have to do with bumps on the skull? To get there we have to add another principle.

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, we can infer which parts of the brain are enlarged and therefore which characteristics are dominant.

By the middle of the 19th century, phrenology machines were in widespread use. 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. 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.

At least this simple model of a compartmentalized brain is true when it comes to basic cognitive functions – such as language, motor control, vision, etc. However, for the higher cognitive functions, such as reality testing, decision making, inhibition of impulses, and similar functions – there is still a significant debate about the big picture of brain organization.

Today the debate is between modules and networks – do specific anatomical brain modules produce specific cognitive functions, or are these function dependent upon a network of connections among various brain regions with any individual region participating in multiple networks simultaneously. I go into more detail about this debate here, but the bottom line is that the answer is likely to be a combination of the two models – brain modules that are wired for specific types of processing, but participating in different networks for specific functions.

So the phrenologists got the compartmentalism thing mostly right, but all of the other assumptions of phrenology are mostly 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.

It is true that the amount of gray matter that is dedicated to a task will increase with use of that task and is larger, as a proportion of brain tissue, in people with talent and skill in a specific area. Musicians have more gray matter dedicated to music, mathematical relationships, and motor control of the hands, than do non-musicians. This effect is only seen when we look at the internal structure of the brain with functional imaging – how much of the brain lights up when we perform a task. It does not affect the overall size and shape of the brain, and bits of the brain do not bulge out with use.

Also, the brain is very jelly-like in consistency. 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 notion of bone changing shape in reaction to underlying pressure is actually reasonable – bone is plastic and will reform to accommodate pressure. Brain tissue, however, is simply not capable of producing such pressure. Some types of brain tumor, on the other hand, are and often changes in the skull seen on X-ray can be a clue to an underlying tumor.

The scientific debate underlying phrenology was addressed over 100 years ago, and answered definitively. While some of the underlying concepts are true or at least reasonable, to a degree, the ultimate conclusion of phrenologists – that the bumps on the skull could be used to divine personality – turned out to be false. 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 blog 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. 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, handwriting analysis, 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, which automatically measured the bumps on 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 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.

Gall made a classic mistake in his methods – functionally he engaged in data mining and then assumed that the patterns he saw reflected underlying reality rather than random chance. He did not appreciate the fact that even if phrenology were completely wrong, he would still find correlations between the skulls of his subjects and their personality. He did not validate the apparent patterns he found with fresh data – by using the original observations to make predictions and then testing those predictions. He was not adequately skeptical of his own conclusions.

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. It is likely that confirmation bias (a tendency to find confirming data and ignore or dismiss disconfirming data) reinforced his belief and confidence in his new system of phrenology.

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 CSI 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 and confirmation bias which lay behind palmistry.

Modern Phrenology

Amazingly, phrenology persists to this day as a pseudoscientific form of divination.  It is marginalized, and has no presence in mainstream science, but it persists none-the-less. There is, of course, a website dedicated to phrenology (phrenology.org) which proclaims:

Phrenology is a true science, which is there to benefit humanity.

Nearly two hundred years after Gall founded his theories, we can look back and assess the real value and impact of Phrenology. Today,  much of the criticism against Phrenology can be easily dismissed. However, we should be careful not to repeat the errors that were done in the past and that, through shameless commercial exploitation or through the pursuit of evil, have disgraced the science and given it a bad reputation.

You might be curious how the site’s author deals with modern criticism of phrenology. He doesn’t. Rather, he addresses the 200 year old criticism that was mounted against Gall – as if it is still relevant today – and then ignores any of the points that are found in this summary.  The site simply asserts that phrenology has been scientifically demonstrate through observation (confusing observation for science) but provides no references. Rather we are treated with positive quotations about phrenology from the likes of Thomas Edison.


Phrenology is certainly an interesting notion from a historical point of view. It emerged out of a largely correct view of neuroanatomy, but then became rooted in clinical practice even while continued progress in neuroscience was rendering it obsolete. Its originator – Gall – combined legitimate basic science with hopelessly naive clinical claims. He can hardly be blamed, as clinical science had not yet been developed and accepted.

Phrenology persisted long past the time that it had been rejected by the scientific mainstream, as practitioners were reluctant to abandon a lucrative procedure, but eventually science won out. By that time it had evolved into just another manifestation of divination through cold reading, and so it is no surprise that it survives as just that.


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,

26 responses so far

26 thoughts on “Phrenology – History of a Science and Pseudoscience”

  1. DevoutCatalyst says:

    “…Amazingly, phrenology persists to this day as a pseudoscientific form of divination. It is marginalized, and has no presence in mainstream science, but it persists none-the-less…”

    Very marginalized, am surprised to hear it’s still on life support. Somewhat related, what do you make of the Rorschach inkblots? Just the text on the box on how they are magically printed only on certain days had me falling out of my chair laughing, yet they seem to get rather slight attention by skeptics, and they are apparently still quite popular.

  2. Calli Arcale says:

    If you are not already familiar with them, you should read the “Discworld” books by Terry Pratchett. In particular, in “Men at Arms”, we get to briefly meet the character of Zorgo, the Retrophrenologist.

    You can go into a shop in Ankh-Morpork and order an artistic temperament with a tendency to introspection. What you actually get is hit on the head with a large hammer, but it keeps the money in circulation and gives people something to do.


  3. Kristoffer says:


    The Rorschach inkblot test and other so called projective personality tests like TAT are still used by some clinical psychologists today. The Rorschach inkblot test should get more attention by skeptics, unfortunately there is a lack of skeptics in the world of clinical psychology, there are still many dogmatic beliefs left.

    There are basically two ways of using projective tests. The first way is to draw conclusions about the tested person. You take this way if you follow the manuals of the tests. This way is not scientific in any way, the validity and reliabilty are very low. This way is just silly. The drawn conclusions depend very much on the psychologist.

    The second way is to use the test as a tool to create hypotheses about the tested personality. These hypotheses then have to be tested against other data from other sources. This way is probably, I hope, the way in which projective tests are used today.

    In my very limited experience, most of the generated hypotheses have to be discarded because other sources don’t support them. It’s a risk that some psychologist keep his hypotheses even though he shouldn’t. That could have negative consequences.

  4. canadia says:

    Its a little disappointing that out of all the possible topics available for you to write about you choose this obscure and dying little subject.

    Aren’t there more relevant topics out there?

  5. HHC says:

    Retrophrenology? Yes, if you hit someone on the head with a hammer, you will alter their physiology and their personality. They will get contusions and concussions. If you do it hard enough and often enough you can actually kill someone. I worked with a forensic patient who did just this repeatedly to his roommate. He didn’t like the guy. His story was in the newspapers.:-{}

  6. HHC says:

    The Beatles put out a song called Maxwell Silver Hammer in 1969. This was about Maxwell Edison who majored in medicine who killed his girlfriend with a silver hammer.

  7. HHC says:

    The song was credited to Lennon and McCartney. The song included a double murder of his teacher and his girlfriend.

  8. HHC says:

    The song actually written by McCartney dealt with the downfalls of life, when things are going well and then down comes silver hammer and it stops. By the end of the song, the character Maxwell Edison kills the judge as he pronounces the judgment in the courtroom.

  9. artfulD says:

    Speaking of songs and killing, they wrote one about Lizzie Borden as follows:
    Lizzie Borden took an axe
    And gave her mother forty whacks.
    When she saw what she had done
    She gave her father forty-one.

    It’s a little know fact that all this happened because she ran out of hammers.

    Another little known but highly relevant fact was that Pete Seeger was a frustrated retrophrenologist – so much so that he wrote a song about it:

    If I had a hammer,
    I’d hammer in the morning
    I’d hammer in the evening,
    All over this land.

    He liked hammers so much he would have become a communist except that he ran out of sickles.

  10. Michael Kingsford Gray says:

    # canadia
    Here’s a suggestion:
    Start your own blog, whilst holding down a demanding job, and doing all of the other things that Steve performs, including several other blogs, preparing to attend TAM, conduct and edit two podcasts, try and see your family on odd occasions.
    If you manage to fill your blog it with always on-topic & always captivating posts, even whilst out of your home state, you have earned the right to complain a little bit.

  11. daijiyobu says:

    If anyone watches the show House, M.D. you will notice from time to time shots of the phrenology model he keeps around his office and conference space.


  12. amwalsh@utas says:

    I wonder if there is another form of phrenology that still persists in society; the left brain/right brain idea.

    Inspired by the skeptics movement, and worried about the amount of pseudoscience I’ve seen creep into my children’s education, I’ve walked away from my career as a wildlife management researcher and now I’m studying fulltime at university to become a primary school teacher. In our visual arts module our lecturer waxed lyrical about people’s personalities and abilities based on how left brain/right brain they were, especially as it related to art. We were encouraged to seek out Betty Edwards’ book Drawing on the Right Side of the Brain.

    A little red flag went up in my mind so I did some Googling and found some interesting online references, plus a book that unfortunately I can’t get hold of (Corballis 1999), which I think pretty much slam dunk this myth, but it’s still a controversial topic. Many of my class mates for example have sided with our lecturer and laugh at me for being so skeptical.

    Maybe Steve could do a post on this topic too to put forward his opinion?

    Here’s some references:

    Calvin, W. H. (1983). Left Brain, Right Brain: Science or the New Phrenology? In The Throwing Madonna. Essays on the Brain. Retrieved on May 10, 2009 from http://williamcalvin.com/bk2/bk2ch10.htm

    Corballis, M.C. (1980). Laterality and Myth. American Psychologist, 38(3), 284-295.

    Corballis, M.C. (1999). Are we in our right minds? In S. Della Sala (Ed.), Mind myths: Exploring popular assumptions about the mind and brain. New York: John Wiley & Sons.

    Harrington, A. (1985). Nineteenth-century ideas on hemisphere differences and “duality of mind”. Behavioural and Brain Sciences, 8(4), 617-659.

    Harris, L. (1985). Teaching the right brain: Historical perspective on a contemporary educational fad. In C.T. Best (Ed.), Hemispheric Function and Collaboration in the Child. Orlando: Academic Press.

    Hines, T. (1987). Left Brain/Right Brain Mythology and Implications for Management and Training. Academy of Management Review, 12(4), 600-606

    Milner, B. (1971). Interhemispheric differences in the localization of psychological processes in man. Neurology, 8, 299-321.

    Mitchell, N. (n.d.) Left Brain Right Brain. The Lab. Retrieved on May 10, 2009 from http://www.abc.net.au/science/features/brain/

    O’Boyle, M. (2004, June 26). Left Brain Right Brain: Fact or Fiction? All in the Mind [Radio broadcast]. ABC Radio National transcript. Retrieved on May 10, 2009 from http://www.abc.net.au/rn/science/mind/stories/s1137394.htm

    Springer, S.P., and Deutsch, G. (1998). Left brain right brain: Perspectives from cognitive neuroscience (5th Ed.). NewYork: W.H. Freeman.


  13. HCN says:

    An interesting book on the early history of neurology that touches on phrenology:

  14. daedalus2u says:

    There have been some attempts to infer brain structure, neural development, and cognitive capacities ( such as language) in extinct primates from skull structure. I think a major difficulty has been insufficient specimens.

    Head size is somewhat determined by the size of the brain, many disorders that cause a reduction in brain size also cause reductions in the size of the skull, for example exposure to radiation in utero which limits neural proliferation and brain size and also causes small head size.

    This observation makes the notion of autism being caused by “toxins” quite problematic because one of the most documented symptoms of autism spectrum disorders is a larger brain with more numerous neurons.

  15. HHC says:

    Some cultures are absolutely fascinated by the size of the head. Hence we have artifacts of shrunken heads and documented methods of shrinkage. Of course, the slang for a psychiatrist in the U.S. is a shrink. In fact, forensics patients thought anyone who tried to change their wild ideas was a shrink.

    Did you know that some Indonesian tribes would eat their enemies brains?

  16. “Did you know that some Indonesian tribes would eat their enemies brains?”

    Talk about floating a big ol’ juicy straight line over the plate! But, every punch line that comes to my mind is X rated.

  17. artfulD says:

    Are you perhaps referring to other enjoyable but less lethal ways of getting their brains out?

  18. artfulD says:

    Or to whether or not our “absolute fascination” with the size of the head really matters?

  19. artfulD says:

    Or to the Seinfeld episode about the “shrunken head”?

  20. Joe says:

    I thought phrenology was dead as a result of Mark Twain’s ridicule of it. If anyone is interested in cold-reading, Ray Hyman has a chapter on it in an inexpensive book: http://csi-store.myshopify.com/products/the-outer-edge

    In addition, there are many articles on that and various “personality tests” at http://www.skepdic.com Look at terms Forer effect, and Myers-Briggs. The latter is a test that many people who go to employment councilors pay a lot of money to take. I bet you can find an astrologer that does the same thing for less.

  21. HHC says:

    Joe, the multiple tests are better than astrology if a whole battery is administered by an experienced clinician for assessment purposes. I was appreciative to have had supervisors at the Iowa state hospitals who like myself were assessed as new employees. Illinois didn’t have this requirement. Needless to say, supervisors showed poor judgment skills on the job. Their attitude was like phrenology. Would you like one lump or two??

  22. artfulD says:

    HHC, are you saying that you were given such tests and the fact that you were then hired proved the tests were accurate?
    Wouldn’t this depend on whether they were testing for a particular set of aptitudes or whether they just wanted to be assured you had any level of aptitude at all.
    Like could you recognize a bedpan when asked to fetch one? Or if so, could you then deal with an Indonesian patient who was desirous of eating your brain?

  23. Joe says:

    @HHC on 29 Jun 2009 at 1:25 pm “Joe, the multiple tests are better than astrology …”

    So … cite the reliable literature supporting your assertion.

    However, be careful to check the reference I supplied- I was specific about Myers-Briggs; and one can include enneagrams, graphology and rumpology (the other “side” (so to speak) of phrenology). They all rely on the Forer effect: tell someone what s/he wants to hear and you will be considered a genius.

  24. HHC says:

    Joe, For some reliable literature, try the Mental Measurement Yearbooks, Buros Institute of Mental Measurements, Lincoln, Nebraska.

  25. Joe says:

    @HHC on 29 Jun 2009 at 8:05 pm “Joe, For some reliable literature, try the Mental Measurement Yearbooks …”

    They are not readily available to me- are you asserting that they validate Myers-Briggs, enneagrams, graphology and rumpology?

  26. stewart says:

    Wide-ranging and interesting discussion (sometimes both).
    I was in Greenwich Village years ago, and walked past a shop offering phrenology, so it’s still around, though perhaps fading.
    The history is worthwhile – although phrenology is clearly a pseudoscience, it had a link to the genuine science of the day, and Gall was a scientist, who went off the rails on this one.
    There was a question about the Rorshach – there’s actually a great deal of discussion in the psychological literature on this, for example several issues of the journal Psychological Assessment were focused on this measure. There’s also a book, ‘What’s Wrong with the Rorschach’, by Wood et al., that reviews the issues. Go to Amazon.com and read the reviews – it gets either 5-star or 1-star reviews, which gives a sense of the polarization involved. Google ‘Lilienfeld Garb psychological assessment’ and you can download a book chapter on the topic.
    Some reactions to these measures (Rorschach, MBTI) are scientific, and some are not (and there’s a lot of pseudoscience in education, especially the learning styles discussion – search out John Gregory Geake and his BERA 2005 presentation on ‘neuroscience and education’.

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