Learning (i.e., operant conditioning)

It is late and 3-year-old Betty is alone in her room. Her parents had just put her to bed not 10 minutes earlier. Her parents are quietly watching television downstairs. Betty begins to cry and after a short time the crying turns into more screaming than crying. Her parents hear her crying and screaming and run up to her room to see what is the matter. Her mother holds Betty in her arms and tells her she is alright. She stops after a few minutes, but when her parents leave her room, she starts crying again. Her father thought that it may be good to bring her down with them and let her lay on the couch while they watch television. Betty is quiet for the rest of the evening, falling asleep on the couch. Betty continues to cry each night for a week and each time her parents take her down to the living room with them until they go to bed or when she falls asleep. Betty's parents are concerned that she will be unable to sleep in her room anymore. Learning (i.e., operant conditioning) has taken place for Betty and her parents. Explain how learning has taken place. If Betty's parents asked you for advice (in operant conditioning terms) on how to get Betty to stay in her room and not cry, what would you tell them?