Decision Fatigue

Why your evening choices look nothing like your morning ones

Sustained mental effort wears down your decision-making over the course of a day, a phenomenon called decision fatigue. Deliberate choices recruit the prefrontal cortex, and recent research shows that extended cognitive work produces chemical changes in that region, including a buildup of glutamate, that make further effortful thinking harder. The result is a bias toward low-effort options: defaulting, delaying, picking "whatever's fine." This isn't laziness. It's the neurochemical cost of a day of thinking.