Devan and ava are studying for their test in u. s. history. devan asks ava, "who was the fourth president of the united states? " ava pauses for a few seconds and then answers, "james madison." as soon as she answers, her cell phone rings. it is her friend carla, and ava talks to her for about ten minutes. when she gets off the phone, devan says, "ava, i didn't hear you. who was the fourth president? " ava thinks for a few moments, and then realizes that she has forgotten. this illustrates the importance of memory: