John suddenly recalled a time he got in trouble with his old…

John suddenly recalled a time he got in trouble with his old high school friend, Tim – someone he had not thought of in years. Later that day, John’s fraternity announced a party hosted by a new pledge named Tim. John declined to go, saying his recent memory was a bad sign there would be trouble at the party. What is the most likely cause of John’s belief?

Smith observes a participant’s brain waves as he sleeps. At…

Smith observes a participant’s brain waves as he sleeps. At one point, Dr. Smith notices that the participant’s brain activity is made up primarily of theta waves, with occasional bursts of electrical activity (spindles) and sharp rising and falling of waves (K-complexes). What stage of sleep is the participant in?