Research in cognitive psychology has established over the past two decades that decision-making capacity degrades with use. Decisions made at the end of the day, or after a series of complex decisions, exhibit characteristic biases that those made in the morning do not.
What subjects observe in a state of decision fatigue
Reduction of the attentional field: attention, ordinarily capable of a certain breadth, progressively narrows. One perceives only what is immediately functional.
Primacy of automatisms: habitual behaviours and familiar interpretations take over without verification. Discrimination is reduced.
Erasure of the meta-observing layer: the capacity to observe one’s own inner state diminishes precisely when it would be most useful. One knows less that one is tired because the resource that would allow one to know is itself depleted.
Awareness of one’s own cognitive limits is not a depressing conclusion. It is operational data that deserves to be integrated into the planning of observation practices.