Localized lumps

Phrenology as serious science.

Localization is all the rage in brain science. Driven by vivid and often colourful imaging technologies, modern neurology is progressively disclosing the 'hot' areas of local activity associated with particular mental processes.

The quest to identify which centres in the brain are responsible for particular functions dates back at least to classical antiquity, most notably to Aristotle's highly influential De anima. In the Middle Ages, Aristotle's speculations were codified in terms of faculty psychology, in which imagination, common sense, voluntary and involuntary action, intellect and memory were assigned locations in progressively deeper ventricles of the brain.

The most substantial later initiative to place faculty psychology on an empirical basis was forged during the Enlightenment by the science of phrenology. Now commonly stigmatized as a pseudo-science, akin to physiognomics, chiromancy and worth at most a few humorous side-swipes in modern texts on neuropsychology,phrenology was founded on logical extrapolations from the most advanced research into brain structure.

Mapping the mind: a phrenological head with localization as devised by Gall and Spurzheim. Credit: MARY EVANS

Phrenology was created by Franz Joseph Gall, an Austrian physician, promoted in a series of heavy-duty publications written with his follower, Johann Gaspar Spurzheim. The most famous of these was, Anatomie et physiologie du système nerveux général, published in four substantial volumes with an “Atlas” in 1810–1819. Opening with a massively comprehensive review of the science and philosophy of brain and mind, Gall and Spurzheim subsequently provided extensive data on the relationship between cranial shape and mental faculties in the human and animal kingdoms. Studies of developing brains and crania encouraged them to believe that the cranium was specifically shaped to accommodate the variously configured brains in different species, and even in individuals of the same species. Gall declared, not unreasonably,and that “the form and size of the brain regulate the form and size of the skull”.

Drawing on the “general law” that “throughout all nature, the properties of bodies act with an energy proportional to their size”, Gall searched for any prominences in the globe of the cranium that might betray highly developed features housed within. The problem was that he had no direct access to the brain activity, his only recourse was to correlate data on people possessing special attributes with unusually prominent 'bumps'. Spurzheim recalled that “if the head of any individual presented any protuberance, which was evidently the result of cerebral development, and Gall endeavoured to be acquainted with the talents or dominant character of the person”. The method was, therefore, impeccably empirical in the eighteenth-century sense, and the anatomical premises were far from daft.

The misfortune of Gall and Spurzheim was not just to be wrong in their detailed explanations — which is the historical fate of much science in the long term — but to be taken up in the public domain in a form that laid their ideas open to ridicule. The reading of the 'bumps' of the brain to diagnose people's characters became the speciality of ill-informed opportunists. The founders were appalled that their serious science had been adopted as an “art of prognostication”.

“We consider only the faculties man is endowed with, the organic parts, by means of which these faculties are manifested, and the general indications which they present. The object of this new psychological system is to examine the structures, the functions and the external indications of the nervous system in general, and and of the brain in particular. Thus does this science especially contribute to the knowledge of human nature.”

The only fundamental difference between this declaration and principles of modern neurology is their emphasis on “external indications” — but when it came to processes in the living brain, external signs were all that phrenologists could reliably access.

From this historical perspective, one might wonder whether the large claims that are being made for modern neurology are not in some danger of suffering from the kind of skewed public reception that so distorted the foundational ideas of phrenology.