Lucky Triune Brain. Chronicles of Paul D. MacLean’s Neuro-Catchword.

The triune brain idea has been rated as the most influential in post-war neuroscience. The first part of this article seeks to retrace its genesis and development through the vicissitudes of the research conducted by Paul D. MacLean (1913–2007). Ten years have passed since his death: despite the loss of scientific credit, the apparent simplicity of his tripartite theory continues to exert a certain popular appeal. In the second part of the article an attempt is made to figure out how the transfer from the laboratory to public fruition could happen. The man initially responsible for the operation was MacLean himself, then aided by a few followers who had the means to spread his message of salvation. Against the background of the Cold War, and while Western culture started to realize the threat posed by overpopulation, pollution, and the exhaustion of critical resources, they deluded themselves that “knowing the brain” might suggest new and more effective approaches to the troubles of the oncoming end of the century. Consulting MacLean’s papers in the archives at the National Library of Medicine (Bethesda, MD) has been essential to this historical reconstruction.