Examines tasks from the heuristics and biases literature in light of the understanding/acceptance principle of P. Slovic and A. Tversky (1974). Shows how the variation and instability of responses can be analyzed to yield inferences about why descriptive and normative models of human reasoning and decision making sometimes do not coincide.…

Proposes a probability heuristic model for syllogistic reasoning and confirms the rationality of this heuristic by an analysis of the probabilistic validity of syllogistic reasoning that treats logical inference as a limiting case of probabilistic inference. Meta-analysis and two experiments involving 40 adult participants and using generalized…