---
The triune brain is a model of the evolution of the vertebrate forebrain and behavior, proposed by the American physician and neuroscientist Paul D. MacLean. MacLean originally formulated his model in the 1960s and propounded it at length in his 1990 book The Triune Brain in Evolution.[1] The triune brain consists of the reptilian complex, the paleomammalian complex (limbic system), and the neomammalian complex (neocortex), viewed each as independently conscious, and as structures sequentially added to the forebrain in the course of evolution.
However, this hypothesis has been subject to criticism,[2] and is no longer espoused by the majority of comparative neuroscientists in the post-2000 era.[3]
The triune model of the mammalian brain is seen as an oversimplified organizing theme by some in the field of comparative neuroscience.[12] It continues to hold public interest because of its simplicity. While inaccurate in many respects as an explanation for brain activity, structure and evolution, it remains one of very few approximations of the truth we have to work with
The simple explanatory value makes this approximation engaging and may be a useful level of complexity for high-school students to begin engaging with brain research.

Triune brain - Wikipedia
