Nathan is being tutored by one his classmates, sarah. nathan wants to ask sarah to the prom but does not know whether she is interested in him. he looks out for signals of encouragement from her and realizes that she does not have a date for the prom. he also notes that she often calls him on the telephone just to talk and joins him for lunch on most days. this encourages nathan to ask sarah out and when he does, she says yes. according to the signal detection theory, this outcome can best be labeled as a