In the context of sleep and circadian rhythms, what is the primary role of melatonin as discussed in AP Psychology?

• A. Melatonin directly causes vivid dreams during deep sleep.
• B. Melatonin increases alertness and energy levels during the day.
• C. Melatonin helps regulate the sleep-wake cycle by signaling the body when it is time to sleep.
• D. Melatonin is responsible for initiating rapid eye movement (REM) sleep.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the context of the question, which is about the role of melatonin in sleep and circadian rhythms as covered in AP Psychology.
2. Step 2: Recall that melatonin is a hormone produced by the pineal gland, primarily involved in regulating the body's internal clock or circadian rhythm.
3. Step 3: Recognize that melatonin levels typically rise in the evening, signaling to the body that it is time to prepare for sleep, thus helping to regulate the sleep-wake cycle.
4. Step 4: Differentiate melatonin's role from other sleep-related processes, such as vivid dreaming or REM sleep, which are influenced by different mechanisms and brain activities.
5. Step 5: Conclude that the primary role of melatonin is to help regulate the sleep-wake cycle by signaling the body when it is time to sleep, rather than causing dreams or increasing daytime alertness.