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Is it possible that psychedelics brought about human language, our huge brains, and essentially all elements of our modern culture? Well, I made a video recently about what psychedelics do in the brain, but a lot of you felt bothered by the statement I made about this idea, the Stoned Ape Theory, being bad. So let’s talk about it! What is the Stoned Ape Hypothesis, and why exactly is it a bad theory? And if magic mushrooms aren’t the answer to how our human brains evolved, what are some of the theories that have maybe a little more support? Pascal Gagneux, PhD, a professor of anthropology and pathology at UC San Diego, joined us to talk about human origins, our relationship to psychedelic substances, and how much chimps love (ordinary, non-magic) mushrooms.

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Our video on the neuroscience of psychedelics:

Our video on the use of scheduled substances to treat psychiatric illnesses:

0:00 I made some people angry
0:55 My background knowledge
2:25 What is this theory?
5:26 How did this become popular?
8:04 The problem with evo theories
12:03 Supporting evidence
13:04 Contradictory evidence
16:01 Alternative explanations
21:30 Questions the theory doesn’t address
26:09 A caveat
27:19 Brilliant ad
28:36 Closing comments

Catlow, Briony J., et al. “Effects of Psilocybin on Hippocampal Neurogenesis and Extinction of Trace Fear Conditioning.” Experimental Brain Research, vol. 228, no. 4, 2013, pp. 481–491., doi:10.1007/s00221-013-3579-0.
Fischer, Roland, et al. “Psilocybin-Induced Contraction of Nearby Visual Space.” Agents and Actions, vol. 1, no. 4, 1970, pp. 190–197., doi:10.1007/bf01965761.
Center for Academic Research and Training in Anthropogeny
Preller, Katrin H., et al. “Effects of Serotonin 2A/1A Receptor Stimulation on Social Exclusion Processing.” Proceedings of the National Academy of Sciences, vol. 113, no. 18, 2016, pp. 5119–5124., doi:10.1073/pnas.1524187113.
Shao, Ling-Xiao, et al. “Psilocybin Induces Rapid and Persistent Growth of Dendritic Spines in Frontal Cortex in Vivo.” Neuron, vol. 109, no. 16, 2021, doi:10.1016/j.neuron.2021.06.008.

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