DreamsDreams

Nature of DreamsNature of Dreams

Functions of DreamsFunctions of Dreams

Objectives Lesson 1Objectives Lesson 1

• To consider key questions in relation to dreaming.

• To be able to describe common features of the content and duration of dreams

• To begin to consider the purpose of dreaming and what different explanations their might be.

Content of DreamsContent of Dreams

• Dreams frequently involve other people & the dreamer is nearly always personally involved.

• Kahn et al (2000) found that half the characters in dreams were known to the dreamer, about a third were more generic characters. Fewer than one in six were completely unknown or novel.

• Dreams have an emotional content. PET scans taken during REM sleep show that the brain regions most associated with emotions are very active.

Content of DreamsContent of Dreams

• Evidence for gender differences show that males dream about other males more than females dream of males (Martin, 2002). This appears to hold across all different cultures & is present in children & adults (Hall, 1984)

• Cartwright et al (1984) studied 90 people who were undergoing marital separation & divorce. Their dream content gave evidence of a strong correlation .

Different kinds of dreamDifferent kinds of dream

REM dreams• Dement & Kleitman (1957) showed that sleepers

who were awoken during REM sleep reported dreaming 80% of the time.

NREM dreams• People reported dreams during NREM sleep but

far less (7%). They tend to be shorter, more mundane and more like fragments of ideas similar to waking thoughts.

Hypnagogic & Hypnopompic statesHypnagogic & Hypnopompic states

• Dream like experiences that occur in the transitional state between wakefulness and sleep.

• People who play a lot of computer games experience ‘screen dreams’ as they fall asleep.

• Pps played tetris for several hours. Many players later reported vivid dreams about it as they fell asleep.

Lucid DreamsLucid Dreams

Dreamers have self-awareness. Fully aware of being in a dream and can control the events taking place.

Dreams are pleasant and straightforward.

Sex is a common theme.

Duration of DreamsDuration of Dreams

• Every 90 minutes = REM sleep

• Dreams run in ‘real time’, some lasting for half an hour (Horne,1999)

• Dreams fade rapidly unless awoken suddenly

• REM dreams vivid relatively long run through ‘real time’

• NREM mundane short, less intense

Test YourselfTest Yourself

• What do PET scans show about the content of dreams?

• What did Cartwright’s evidence suggest about the content of dreams?

• Is it true that time runs slower in dreams?

• What kind of biological rhythm could we call dream cycles? How long between each cycle?

Objectives Lesson 2Objectives Lesson 2

• To be able to describe Psychological theories of the function of dreams (Freud and Cartwright)

• To evaluate these theories

• To be able to use supporting/opposing evidence to evaluate the theories

Explanations of dreamingExplanations of dreaming

• Psychological theories

(Dreams have meaning)– Ego defence (Freud)– Problem solving (Cartwright)

• Physiological/Neurobiological theories

(Dreams have no meaning)– Reverse learning (Crick & Mitchison)– Activation synthesis (Hobson & McCarley)

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Freud and DreamsFreud and Dreams

• Dreams protect sleeper from irrational urges coming from id. They allow the release of potentially dangerous energy which would otherwise lead to insanity.

• Dreams therefore mainly ‘wish fulfullment’

• Dreams nature made up of manifest and latent content.

• Dreams ‘royal road’ into the unconscious mind

Cartwright and Problem SolvingCartwright and Problem Solving

• Cartwright dreams directly reflect our major emotional concerns

• Problem solving takes place during dreaming—deal with preoccupations of waking life.

• Dreams provide solutions for work-Kekule and structure of benzene

• Dreams provide coping strategies for emotional problems. Mind finds symbols that fit the pressures of the moment.

Commentary Freud Commentary Freud

• Theory difficult to falsify• Theory based on culturally and historically biased

sample of neurotics Viennese woman.• However, PET scans show rational brain switched off

during dreaming while forebrain—centre of motivation memory is fully activated—so no ego but id active.

• Solms shows dreams activated by forebrain not brain stem.

• Dreamwork - Condensation supported by computer simulation research.

• Are all dreams wish fulfillments—i.e nightmares?

Commentary on CartwrightCommentary on Cartwright

• Barrett 1993 studied students who were instructed to solve a problem. Over a week a panel of independent judges found 50% dreamt a solution.

• Stickgold 2000 found Tetris players dreamt solutions to problems connected to the game.

• Cartwright 1984 found couples separating had dreams relating to their waking coping strategies

Objectives Lesson 3Objectives Lesson 3

• To be able to describe Neurobiological theories of the function of dreams

• To evaluate these theories

• To be able to use supporting/opposing evidence to evaluate the theories

Hobson and McCarleyHobson and McCarley

• Activation-Synthesis. Random internally generated signals from brainstem are ‘synthesized’ by frontal cortex.

• Bizarre nature of dreams is the lack of information that brain does its best to interpret and give meaning.

• Conclusion personal but meaningless.

Crick and MitchisonCrick and Mitchison

• Reverse Learning—we dream to forget.

• Parasitic associations clog up our processing mechanisms making us function inefficiently

• Dreaming clears out these unwanted memories• Other unwanted memories are also expelled including

those that might be pathological—that is obsessional.

• Neural networks are kept compact and efficient

Crick and MitchisonCrick and Mitchison

• Reverse Learning—What happens?

• The BRAINSTEM bombards the FOREBRAIN

• This excites the neurons in the FOREBRAIN and loosens the conections responsible for unnecessary “parasitic” memories

• Dreams are the “By-product” of this process

Commentary on Neurobiological TheoriesCommentary on Neurobiological Theories

• Goertzel 1997 estimates 100 billion billion bits of information taken in by brain during a lifetime but brain has only space for 100 billion bits

• Negative correlations between brain size and REM sleep predicted by theory and found.

• Mammals without REM sleep have larger brains.• However, Reverse learning can not explain why dreams

are meaningful• Christos 1996 has shown that computer simulations give

little support for theory• Capacity of storage for human brain may be

underestimated.

• Pet scans give support to Activation-Synthesis—ie. Brain stem active prefrontal cortex not active—frontal lobe active

• Explains why dreams are without ‘smell’ as that part of brain inactive.

• Animal studies show acetylcholine is the ‘firing’ agent in the brain stem. No acetylcholine no dreams.

• However, Solms 2000 found injuries to brain stem REM stopped but dreaming did not.

Essay Plan – Discuss the Essay Plan – Discuss the nature of dreams (25)nature of dreams (25)

• Intro – Briefly discuss the nature and content of dreams. Distinguish between REM and NREM dreams.

• Controversial question is whether dreams have significant meaning or not – explain there are two theories to support both sides of this argument Psychological (Meaning) and Neurobiological (No meaning).

• AO1 Describe Freudian theory • AO2 Evaluate Freudian theory with supporting and opposing evidence• AO1 Describe Cartwright’s theory• AO2 Evaluate Cartwright’s theory with supporting and opposing evidence• AO1 Describe Activation-Synthesis• AO2 Evaluate Activation synthesis with supporting and opposing evidence• AO1 Describe Reverse Learning Theory• AO2 Evaluate Reverse Learning Theory with supporting and opposing

evidence• Summarise points and make point about problem with both theories.