Joe Rogan on evolution: what the evidence says · JRE #2152
SUBJECT: EVOLUTION
Not a true/false call. Every claim is logged with its sources; read the exhibits below.
I think most biologists will agree that the biggest mystery in the entire fossil record is the doubling of the human brain size over a period of 2 million years.
What the evidence says 01 / RECORD
Hominin brain size did roughly triple (not merely double) from early Australopithecines to modern Homo sapiens over several million years, a rapid change relative to typical mammalian encephalization rates, and the precise causal weighting of contributing factors remains an active research question. However, paleoanthropology does not treat this as an unsolved mystery: peer-reviewed work has proposed and quantitatively tested multiple, non-mutually-exclusive drivers, including ecological problem-solving, social/cooperative demands, and cultural transmission, with a 2018 Nature study modeling brain-size evolution as driven by a combination of roughly 60% ecological, 30% cooperative, and 10% between-group competitive pressures, further promoted by culture. This body of research explicitly aims to "refine, refute and unify" competing hypotheses rather than treating brain growth as an inexplicable anomaly. The claim that "most biologists" regard this as the single biggest mystery in the fossil record is an overstatement not supported by the current scientific literature, which frames it as a well-studied, multi-causal phenomenon with ongoing debate over relative contributions rather than a total mystery.