Annoyance didn't mention this explicitly in his post about frontal syndrome, but these readiness heuristics are related to the frontal lobe of the brain in some way, and can be damaged with interesting results. Damasio describes a patient with a frontal stroke who lost the ability to terminate the decision-making process. He told the story of (I think I remember this right) trying to schedule an appointment with this patient, and told him that either Tuesday or Thursday would work, and the patient spent the next several minutes listing all the possible reasons why one day might be better than the other and balancing them out. When it became overwhelming, Damasio finally just said "What about Thursday?" and the patient immediately agreed.