Cognitive Bias & Energy
topic
Cognitive biases — the systematic shortcuts (heuristics) that System 1 (fast, automatic, intuitive) thinking uses in place of the slower, more energy-intensive deliberate reasoning of System 2 — are fundamentally energy-saving mechanisms: the brain defaults to biased fast processing to conserve the significant glucose and attentional resources that careful deliberate evaluation requires, with cognitive depletion reliably increasing the use of biased heuristics in proportion to the depletion of deliberate processing capacity.
Role
The relationship between cognitive energy depletion and cognitive bias adoption is the most consequential implication of decision fatigue research — because it means that cognitively depleted people are systematically more biased in their judgments than the same people making the same judgments with adequate cognitive resources. The decisions made in the late afternoon by a fatigued executive are measurably less rational, more confirmation-bias-driven, and more heuristic-dependent than the morning decisions of the same executive — yet the executive has no subjective experience of this degradation because depleted System 2 has reduced oversight of System 1 as part of the depletion itself.