A randomized trial says AI may make experienced devs slower while they feel faster — and the gap may be narrowing as tools improve, but the perception/reality bias is still real. A survey of 319 knowledge workers says AI shifts thinking from synthesis to stewardship; a separate 666-person study found a strong negative correlation between AI use and critical thinking. The new HBR/BCG "AI brain fry" study put hard numbers on the agent-supervision burnout pattern. The neuroscience offers one plausi...