Unit V: States of Consciousness Module 23-Sleep Patterns & Sleep Theories AP Psychology

Circadian Rhythm Circadian rhythm and age Circadian rhythm-our “biological clock,” regular body rhythms 24 hour cycle Temperature changes Body temp rises in the morning, peaks during the day, dips in the early afternoon, & drops in the evening Circadian rhythm and age Typically, teens/young adults are at their peak as the day progress Older adults tend to see their performance decline as the day progresses This shift usually occurs around 20 (slightly sooner for women)

Brain Waves Alpha Waves-relatively slow brain waves of a relaxed, awake state Beta Waves-brain waves during a heightened states of alertness, logic and critical reasoning can translate into stress, anxiety and restlessness Delta Waves-usually associated with the deep stage 3 of NREM sleep Theta Waves-present during deep meditation and light sleep REM dream state

Sleep Stages Two distinct types of sleep: REM Sleep-rapid eye movement sleep; also known as paradoxical sleep, because the muscles are relaxed (except for minor twitches) but other body systems are active Vivid dreams are typical during this stage of sleep NREM Sleep-non-rapid eye movement sleep; encompasses all sleep stages except for REM sleep.

Sleep Stages We typically go through 4 sleep stages every 90 minutes: NREM1 slow eye movement. sometimes referred to as relaxed wakefulness Alpha waves begin to disappear People aroused from this stage often believe that they have been fully awake NREM2 no eye movement occurs dreaming is very rare The sleeper is quite easily awakened

Sleep Stages We typically go through 4 sleep stages every 90 minutes: NREM3 deep sleep dreaming is more common in this stage than in other stages of NREM sleep (though not as common as in REM sleep) REM rapid eye movement, increased heart beat, irregular breathing vivid dreams commonly occur Also known as paradoxical sleep, because the muscles are relaxed (except for minor twitches) but other body systems are active

Sleep Stages Although the stages are numbered NREM 1, 2, 3, REM; they don’t occur in that order: Typically, NREM 1 occurs first NREM 2 NREM 3 REM The cycle repeats every 90 minutes or so As the night goes on, NREM 3 sleep becomes shorter & disappears REM & NREM 2 periods get longer

Sleep Stages

What Affects Our Sleep Patterns? Suprachiasmatic nucleus (SCN)-a pair of cell clusters in the hypothalamus that controls circadian rhythm. In response to light, the SCN causes the pineal gland to adjust melatonin production, thus modifying our feelings of sleepiness. Melatonin-hormone that induces sleep

HW-Using your textbook and/or other sources, identify and explain the 5 reasons psychologists believe that sleep might have evolved in humans.