Psychology - Sleep and Dreams

• Circadian Rhythm is where all species have a timing mechanism, or internal body clock that controls periods of activity and inactivity across a day, a season, or a year. The circadian rhythm is 24 hours long.

  The SCN is the main controller of many circadian rhythms and acts like an internal pacemaker. Used to reset the biological clock.
• Without zeitgebers, the body can not entrain (reconnect) itself properly to the day-night cycle. Zeitgebers are environmental triggers that refer to environmental signals that affect our circadian rhythm. When all-natural light cues are removed, these body clocks begin to operate on their schedule.
• Siffre (1962) spent 6 months underground with no cues as to time. His circadian rhythm extended to 25 hours which shows that zeitgebers keep us entrained to a 24 hour period.
• Factors that affect sleep: drugs, alcohol, and light.
• Drugs are a stimulant drug which has the effect of making people more alert or keeping them awake and can reduce the quality of sleep. Example; caffiene.
• Alcohol usually makes people feel sleepier. Drinking in the evening changes the proportions of REM + nREM sleep.
• Light will boost your ability to sleep
• Stages of sleep. sleep begins in stage 1 and progresses into 2,3, and 4 and after stage 4, stage 3 and 2 are repeated before entering rapid eye movement (REM)
• stage 1, is the light stage of sleep. Can be considered a transition period between wakefulness and sleep. The brain produces high-amplitude theta waves (very slow brain waves). Stage one lasts between 5-10 minutes.
• Stage 2, lasts 20 minutes. The brain begins to produce bursts of rapid, rhythmic brain wave activity known as sleep spindles. Body temp starts to decrease and heart rate slows down.
• Stage 3, Deep, slow brain waves known as delta waves
• Stage 4, delta sleep. Lasts about 30 minutes and is known as deep sleep, bed wetting and sleep walking.
• Stage 5, is REM (rapid eye movement) and its were most dreaming occurs.
• Three types of brain waves = Alpha, Theta and Delta
• Alpha and theta waves are found in stages 1 and 2. Starting with alpha and progressing into theta
• Alpha waves are known to calm down and promote feelings of deeper relaxation and content. High level of alpha waves can lead to day dreaming.
• Theta waves are involved in restorative sleep. Usually classed as suggestive waves because they are the waves that are seen when someone is being hypnotized. Also links with us feeling deep, raw emotion.
• Delta waves are associated with deep levels of relaxation and restorative sleep. Occur during sleep stages 3 + 4.
• The restoration theory of sleep was proposed by Oswald(1966) and he proposed that sleep is the period of inactivy necessary for the body and brain to replenish themselves, to repair any damage sustained during the day. Oswald said that short-wave sleep is for restoring the body in terms of physical activity and whilst REM sleep is for resting the brain functions.
• Case of Peter Tripp: New York DJ who set a world record for sleep deprivation in 1959. He went 201 hours which is 8.4 days without sleep. He became psychotic in which he hallucinated that he could see spiders he also became paranoid. By 110 hours there were signs of delirium. Tripp saw a suit of worms.
• Lavie et al (1984): 33-year-old man who experienced almost no REM sleep for the past 13 years. This was a result of a traumatic brain injury. Thirty-five years later he was re-examined and this showed he was still experiencing no REM sleep. Yet he showed average to high cognitive functioning normal memory.
• nREM sleep is new tissue growth, muscle repair, and removal of waste chemicals. REM sleep is to replenish neurotransmitters and keeps us alert.
• Can also be linked with the following studies.

  Shapiro et al(1981) - ultramarathon runners

  Rat study - healing process

  Horne and Harley(1988) - hair dryer method
• Restoration theory could be compared to the reorganisational theory.
• strengths and weaknesses of the restoration theory:

  Strengths: backed up by evidence and real-life

  Weaknesses: to simplistic
• Activation-synthesis theory: the biological process believes the restoration theory explains why, but it looks to the activation-synthesis theory for an explanation for why we dream. This theory sees dreams as essentially random and meaningless.

  Horban and McCarley (1977) believe that dreams are just randomly activated messages
• Dement and Klietman (1957):

  Lab experiment

  Procedure: 9 participants, 7 being male and 2 being female.

  Method: participants came to the lab just before their usual bedtime. They were asked to avoid caffeine and alcohol on the day of the study. They went to bed in a dark quiet room. An EEG was used to record signals and they were woken at various times to test dream recall.
• Strengths: high level of control due to the participants being asked to avoid caffeine and alcohol, also done in a lab.


  Weaknesses: lacks ecological validity because of the unnatural sleeping location which could have effected their sleeping patterns and the sample size was not equal so could be generalised.
• Cognitive Process Relating to Sleep and dream: focuses on the role of sleep in memory and thinking. The mind is a processor of information. During sleep, the mind can clear up unnecessary items.
• Strickgold(2009) - investigated the processes by which memories develop during sleep. According to his research sleep can be of benefit to every type of memory.
• Mendrick et al (2003) - found that for a preception task, the same benefits were found after a 90-minute nap (containing all sleep stages).
• Seehagen et al (2015) - found that when babies were learning s new action those who had taken a nap showed better recall.
• Reorganisational theory: Crick and Mitonison (1983) suggest that the role of dreaming is to delete unwanted memories"reverse learning." It would predict links between what we think about during the day and what appears in our dreams.
• Parasitic memories = bad like parasites

  Apative memories = good they help survival

  we keep the adaptive and throw away the parasitic.
• In conclusion reorganisational theory suggest that dreaming is purely to unlearn useless information.
• This theory implies that our dreams are random and meaningless.

  Strength of reorganisational theory = gives a clear reason

  Weakness of reorganisational theory = not enough evidence
• Shift work - negative results of shift work are sleep deprivation, poor quality, job stress, and risk of heart disease.
• Cziesler et al (1990) -

  aim - to evaluate exposure to bright lights at night and darkness during the day.

  method - 8 males, 2 conditions, control + treatment, 2 weeks of nightshift. Treatment group with extremely bright lights, control group with normal lights

  results - treatment group slept 2 hours longer and were more alert

  weakness - biased sample, could not be generalised
• Bovian et al (1996) - put 31 male participants on an inverted sleep pattern, each day when they woke they were sat in front of dim lights for 5 hours and then placed in one of four conditions:

  • very bright lights
  • bright light
  • ordinary room light
  • continued dim light
• Bovian et al (1996) - core body temp was recorded and used as a measure of how well they were adapting to the new rhythm after 3 days.

  findings -

  • group 1 - advanced by 5 hours, adapted the best
  • group 2 - by 3 hours
  • group 3 - by one hour
  • group 4 - drifted back by one hour