{"id":1798,"date":"2026-07-16T13:42:39","date_gmt":"2026-07-16T11:42:39","guid":{"rendered":"https:\/\/brainhelpdesk.nl\/en\/?post_type=vraag&p=1798"},"modified":"2026-07-17T13:06:38","modified_gmt":"2026-07-17T11:06:38","slug":"do-we-really-have-a-reptile-brain-a-mammal-brain-and-a-human-brain-inside-our-heads","status":"publish","type":"vraag","link":"https:\/\/brainhelpdesk.nl\/en\/vraag\/do-we-really-have-a-reptile-brain-a-mammal-brain-and-a-human-brain-inside-our-heads\/","title":{"rendered":"Do we really have a reptile brain, a mammal brain, and a human brain inside our heads?"},"content":{"rendered":"\n

What is the Triune Brain Theory<\/strong><\/h2>\n\n\n\n

In 1949, Paul MacLean introduced the triune brain model (\u201ctriune\u201d being an old, almost biblical term meaning \u201cthree-in-one\u201d), describing the brain as made up of three parts: a primitive \u2018reptilian\u2019 region associated with survival behaviors and basic bodily functions; a \u2018paleomammalian,\u2019 or limbic, region linked to emotions and additional cognitive processes; and a \u2018neomammalian\u2019 region, including the neocortex, responsible for integrating emotion and thought and supporting advanced abilities such as language and abstract reasoning. This theory proposes that our human brain evolved in successive layers: with the limbic (mammalian) and neocortical (human) regions built on top of an older reptilian core. <\/p>\n\n\n\n

You will still come across this explanation in popular psychology textbooks or online blogs (like this one: https:\/\/bureausnugger.nl\/reptielenbrein-zoogdierenbrein-neocortex\/<\/a>) that suggest this is how our ‘brain’ or ‘mind’ works. However, in this article, we will explain why neuroscientists consider this view not only oversimplified but also plain wrong.<\/p>\n\n\n\n

Evolution is not a straight line!<\/strong><\/h2>\n\n\n\n

To unlock the mysteries of the human brain, many neuroscientists turn to the brains of other animals in a field known as ‘comparative neuroscience’. At the lab of Professor Gilles Laurent at the Max Planck Institute for Brain Research in Frankfurt (https:\/\/brain.mpg.de\/laurent<\/a>), we study uncommon animals like central bearded dragons and cuttlefish (see Figure 1<\/strong>). These are creatures with brains shaped by unique ecological challenges, from rapid camouflage to complex social signaling. While these species share some brain structures with humans, their solutions to survival and cognition are strikingly different!<\/p>\n\n\n\n

Their cognition isn’t about stacking brains like layers of an onion. Instead, evolution has taken parallel, divergent paths: each species building a brain suited to its own world. By studying these diverse systems, we uncover fundamental principles of brain function that are hidden when we only look at humans.<\/p>\n\n\n\n

\n
\n
\"\"<\/figure>\n<\/div>\n<\/div>\n\n\n\n

Figure 1<\/strong>. Photos of a central bearded dragon (Pogona vitticeps<\/em>, left) and a couple of cuttlefish (Sepia officinalis<\/em>, right). These evolutionarily distinct animals serve as key models for understanding how neural circuits and behavior adapt to unique ecological challenges. Image by Stephan Junek (Max Planck Institute for Brain Research).<\/p>\n\n\n\n

Shared brain features?<\/strong><\/h2>\n\n\n\n

One thing that\u2019s true about evolution is that we all share common ancestors that had similar kinds of brains. Sometimes, our most distant shared ancestor is very far back in the evolutionary tree, like with the cuttlefish: a mollusk and invertebrate (species without \u2018vertebrae\u2019, or \u2018backbone\u2019), while we are mammals and vertebrates (we have backbones). In other cases, our shared ancestor is much closer, such as with primates like chimpanzees or macaques. This is reflected in how similar our brains are. With birds and reptiles, we share key brain regions involved in emotion and movement, such as the amygdala and basal ganglia. This is because humans, birds, and reptiles all share a common vertebrate ancestor.<\/p>\n\n\n\n

The neocortex (this is a six-layered structure that we use for complex thought) is unique to mammals. Both birds and reptiles lack a neocortex. To compensate for this, however, birds have evolved another highly developed region we call the pallium, while reptiles have a simpler three-layered cortex. Remarkably, birds like crows and parrots show very complex behaviors, despite their different brain layout! Think about crows using sticks as tools or parrots that imitate speech. Nature seems to have found more than one route to a clever mind. Octopuses, for instance, evolved their nervous systems on a separate branch of the tree of life from ours, yet they still display remarkably sophisticated behavior. It’s a reminder that you don’t need a brain built like ours to be smart. For more on how animal brains can diverge from our own, see our answer to “<\/a>Are there people or animals with more or fewer than two brain hemispheres?”<\/a>.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

(A)<\/strong> A diagram showing the evolutionary tree of vertebrates, with a focus on different reptiles. On the right, drawings of vertebrate brains (side view, facing the left side of the brain) show examples from different species: a fish, an amphibian, a reptile, a bird, and a mammal. Key brain regions are present in all species, though in different sizes. (B) <\/strong>A view inside the right hemisphere of brains from different vertebrates: a fish, an amphibian, a reptile, a bird, and a mammal. The colours represent shared brain regions that have been conserved across species. Figure originally from Naumann et al., 2015 in Current Biology<\/em>.<\/sub><\/p>\n\n\n\n

Why each brain is an \u2018end-product\u2019 not a \u2018building block\u2019<\/strong><\/h2>\n\n\n\n

Brain regions have evolved together and are deeply interconnected: areas responsible for emotions, reasoning, and survival constantly interact, which is crucial to any animal\u2019s ability to survive and reproduce. It\u2019s more accurate to think of the brain as an integrated network, shaped by millions of years of natural selection, both in humans and in other species. Yes, we share certain brain structures with other animals. But sharing is not the same as inheriting. Think of it like a family recipe that gets tweaked with every generation: the dish your grandmother made and the one you make today may share the same basic ingredients, but they are not the same recipe. In the same way, brain structures that look similar across species have each been shaped by millions of years of independent evolution. A human’s emotional brain is not a lizard’s emotional brain with a thinking cap on top! <\/p>\n\n\n\n

So rather than thinking of the human brain as a series of layers stacked through time, think of it as a completely unique system that happens to share some deep roots with other animals. Each brain (including ours) is a fully functional end-product of its own evolutionary story. So, the next time someone claims they’re using their ‘reptile brain’ or ‘instinct’, you can throw in a little evolutionary wisdom and prove them wrong!<\/p>\n\n\n\n

Read more?<\/h2>\n\n\n\n

[English] <\/strong>https:\/\/scienceandculture.com\/2023\/06\/reptilian-brain-myth-is-still-alive-and-kicking\/<\/strong><\/a><\/strong><\/p>\n\n\n\n

[English] <\/strong>Naumann, R.K., Ondracek, J.M., Reiter, S., Shein-Idelson, M., Tosches, M.A., Yamawaki, T.M. and Laurent, G., 2015. The reptilian brain. Current Biology<\/em>, 25<\/em>, pp.R317-R321<\/p>\n\n\n\n

[English] <\/strong>https:\/\/www.sciencedirect.com\/topics\/neuroscience\/triune-brain<\/strong><\/a><\/p>\n\n\n\n

[English] <\/strong>Zaremba B, Fallahshahroudi A, Schneider C, Schmidt J, Sarropoulos I, Leushkin E, Berki B, Van Poucke E, Jensen P, Senovilla-Ganzo R, Hervas-Sotomayor F, Trost N, Lamanna F, Sepp M, Garc\u00eda-Moreno F, Kaessmann H. 2025. Developmental origins and evolution of pallial cell types and structures in birds. Science 387:eadp5182. DOI: https:\/\/doi.org\/10.1126\/science.adp5182<\/p>\n\n\n\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

What is the Triune Brain Theory In 1949, Paul MacLean introduced the triune brain model (\u201ctriune\u201d being an old, almost biblical term meaning \u201cthree-in-one\u201d), describing the brain as made up of three parts: a primitive \u2018reptilian\u2019 region associated with survival … Lees verder…<\/span><\/em><\/a><\/em><\/p>\n","protected":false},"author":7,"featured_media":0,"template":"","meta":{"_acf_changed":false,"footnotes":""},"categories":[40,35],"class_list":["post-1798","vraag","type-vraag","status-publish","hentry","category-physiology","category-intelligence"],"acf":[],"_links":{"self":[{"href":"https:\/\/brainhelpdesk.nl\/en\/wp-json\/wp\/v2\/vraag\/1798","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/brainhelpdesk.nl\/en\/wp-json\/wp\/v2\/vraag"}],"about":[{"href":"https:\/\/brainhelpdesk.nl\/en\/wp-json\/wp\/v2\/types\/vraag"}],"author":[{"embeddable":true,"href":"https:\/\/brainhelpdesk.nl\/en\/wp-json\/wp\/v2\/users\/7"}],"version-history":[{"count":14,"href":"https:\/\/brainhelpdesk.nl\/en\/wp-json\/wp\/v2\/vraag\/1798\/revisions"}],"predecessor-version":[{"id":1820,"href":"https:\/\/brainhelpdesk.nl\/en\/wp-json\/wp\/v2\/vraag\/1798\/revisions\/1820"}],"wp:attachment":[{"href":"https:\/\/brainhelpdesk.nl\/en\/wp-json\/wp\/v2\/media?parent=1798"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/brainhelpdesk.nl\/en\/wp-json\/wp\/v2\/categories?post=1798"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}