P. Walker is working on direct current stimulation as a cure for sleeplessness in the aging brain. Which of the following statements is most likely TRUE about Professor Walker's research?
1. Adults over the age of 60 don't need eight hours of sleep each night, so Professor Walker is examining how little sleep is adequate for optimal functioning if a patient has poor sleep.
2. Professor Walker is considering drug therapies, as elderly patients already take plenty of medications, so an additional prescription should not be a problem.
3. Professor Walker is considering the impact of sleep deprivation on health, as elderly individuals who have poor sleep will have impairments due to it.
4. Adults over the age of 60 rarely experience any form of poor sleep, so Professor Walker is studying the daytime napping schedules of the elderly so he can help younger individuals to improve their functioning.