The New York Times reports that Paul D. MacLean, a neuroscientist who developed the theory that the brain is divided into three broad areas that developed during different phylogentic phases of evolution, died on December 26 at the age of 94. According to Jeremy Pearce, who wrote the Times‘ obituary:
In the 1960s, Dr. MacLean enlarged his theory to address the human brain’s overall structure and divided its evolution into three parts, an idea that he termed the triune brain. In addition to identifying the [mamalian] limbic system, he pointed to a more primitive brain called the R-complex, related to reptiles, which controls basic functions like muscle movement and breathing. The third part, the neocortex, controls speech and reasoning and is the most recent evolutionary arrival.
Although the “triune” theory of the brain was never fully accepted in the scientific community, it became a standard scheme in neuroscience and psychology textbooks in the last quarter of the 20th century.
There is much to say about Paul MacLean. I would like to honor this great neuroanatomist and this great writer on anatomy, with two comments.
The first from his equally great contemporary, Paul Yakovlev,
“MacLean was the first to recognise in his 1949 paper “Psychosomatic Disease and the ‘Visceral Brain'” that Papez’s [referring to James W. Papez, and his last name said Papes, as MacLean often pointed out] tentative ‘propostion’ that emotions have a physiologically explorable and anatomically definable machinery was a true discovery and not a ‘delusion’ as had hitherto been widely held. Since then MacLean has demonstrated experimentally, in depth, the epistemic valditiy of this disocvery.”
P. I Yakovlev (1978); Limbic MEchansims (K. E. Livingston, and O. Hornykiewicz eds). Chapter entitled: Recolections of JAmes Papez and Cmments on the Evolution of the Limbic System Concept, Plenum Press
The second reference to MacLean’s work is from J. R. Durant
MacLean’s work represents an island of accessible and wide-ranging generalizations in an ocean of abstruse and arcane technicalities. Drawing on themes that have been influential in our culture for generations, it provides an ambiotious synthesis of biology and psycholgoy that reinforces everyday or commonsense perceptions of human beastliness and offers apparently authoritative judgments concerning human health and happiness
J. R. Durant , The Science of Sentiment: The Problem of Cerebal Localization of Emotion, Plenum