Evolution of intelligence in our ancestors may have come at a cost

https://www.newscientist.com/article/2499487-evolution-of-intelligence-in-our-ancestors-may-have-come-at-a-cost/

Ancient Lead Exposure Influenced the Evolution of the Human Brain

https://bioengineer.org/ancient-lead-exposure-influenced-the-evolution-of-the-human-brain/

Evolution may have capped human brain size to balance energy costs and survival

https://www.psypost.org/evolution-may-have-capped-human-brain-size-to-balance-energy-costs-and-survival/