Jaden has a horrible pain on his right side, a symptom that is prototypical of appendicitis. Even though he does not have any of the other symptoms of appendicitis, he is convinced he has it and goes to the emergency room. He is mortified to learn that all he had was a bad case of gas. Because Jaden's error was based on the prototype of the symptom he had, he relied on the ______________ heuristic.