Much research in the last 2 decades has demonstrated that humans deviate from normative models of decision making and rational judgment. In 4 studies involving 954 participants, the authors explored the extent to which measures of cognitive ability and thinking dispositions can predict discrepancies from normative responding on a variety of tasks from the heuristics and biases literature including the selection task, belief bias in syllogistic reasoning, argument evaluation, base-rate use, covariation detection, hypothesis testing, outcome bias, if-only thinking, knowledge calibration, hindsight bias, and the false consensus paradigm. Significant relationships involving cognitive ability were interpreted as indicating algorithmic-level limitations on the computation of the normative response. Relationships with thinking dispositions were interpreted as indicating that styles of epistemic regulation can predict individual differences in performance on these tasks.