The cognitive miser theory suggests that the human brain is evolved to conserve energy by defaulting to fast, low-effort mental shortcuts (heuristics) instead of taxing, analytical thinking. Because deep reasoning is metabolically expensive—consuming significant glucose and oxygen—we naturally act as “misers” to preserve these finite resources. This leads us to prioritize efficiency over accuracy, often resulting in biases like motivated reasoning or identity-protective cognition to avoid the “cost” of changing our minds.