Ultradian Rhythms

Question 0

Dement and Kleitman: sleep lab

Answer 0

• Sleep consists of clearly differentiated stages of brain activity.
• 9 ppt up to 61 nights in lab, waking them during each stage.
• All ppts showed quite considerable similarity in their sleep cycles. -Found 80-90% of ppts reported dreams during REM wakening
• Whereas only 7% recalled dreams from NREM awakening.
• Findings stand tests of time; accepted by scientific community in providing ^ES for the 5 stages of sleep.

Question 1

The stages of sleep (Alpha, Theta, Delta, Beta)

Answer 1

• Ultradian rhythms repeat more than once every 24 hours.
• Within SW/c UR of stages of sleep exists.
• 5 stages of sleep each cycle lasting approximately 90 minutes.
• NREM sleep (1-4) progresses from shallow to deep sleep.
• Back through stages 3-2- a short period of REM sleep, get longer during the course of the night.
• Stage 1 and 2 of NREM brain produces alpha and theta waves causing v HR v BT, sleeper in relaxed state and easily woken.
• stages 3 AND 4 of NREM delta waves initiate deep sleep.
• physiological repair/biochem processes take place.
• REM brain produces beta waves resemble the awake brain.
• known as paradoxical sleep as brain, eyes and major organs are active but body paralysed. REM is associated with dreaming.
• Regular 90 min cycle suggests BM/EP alternately cause NREM and REM.
• // the stages of sleep are also influenced by EZ ie alcohol, caffeine and exercise.

Question 2

Dement: v population validity

Answer 2

• lack of population validity, scarcity of middle aged volunteers.
• Dement acknowledges that this is due to them being busy with family and work life hence they find less time for sleep research.
• Ironically, their lifestyles put them most at risk of sleep disorders.
• Making them more valuable subjects for Sleep research.
• Sleep knowledge limited due to inadequate sampling; undermines the 5 stage explanation.

Question 3

Foulkes: 70% NREM

Answer 3

• Regardless, some contradictory R reported figures as high as 70% for dreams during NREM sleep.
• Foulkes attributed this to confusion as to what constitutes a dream
• Dreams are subjective so can be confused with muddled thoughts.
• Although REM identified by objective measure of brain activity there is no objective measure to accurately record dreams all relies on self reports.

Question 4

Psychology as a science

Answer 4

• ^internal validity due to scientific approach in a lab setting.
• offers support to the debate of psychology as a science.
• Evidence is provided for BM behind sleep.
• // to measure sleep physiologically willing ppt wired up to machines which must affect the quality and quantity of sleep.
• Although R = ^ IV it lacks EV as it doesn’t reflect range of factors which influence real-life sleep i.e co-sleeping.
• Exp are undermined by a lack of practical application.