OCR AS Psychology Physiological Approach

Basic information on each of the studies and the approach

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Physiological Approach

  • The approach assumes that all our behaviour has a biological basis and is the result of our genes, hormones, biochemistry etc
  • It takes the nature side in the nature/nurture debate
  • Strengths of this approach include: it gives us a greater understanding of the brain, scientfic - uses objective measurements, highly controlled and establishes clear cause and effect
  • Weaknesses include: it oftens relies on self report, there can be errors in technology, it's reductionist and has low ecological validity
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Dement and Kleitman (1957)

Aim

  • To see if physiological aspects of REM sleep related to the subjects' psychological experience of dreaming

Hypothesis

  • Association between REM and reported dreaming
  • Significant positive correlation between estimated time of dreaming and measurement of REM sleep
  • Relationship between pattern of eye movement and reported dream content

Method and Design

  • Lab experiment
  • Repeated Measures (same condition for 61 nights)
  • 9 participants (7 males and 2 females)

IV

  • Woken up during REM sleep or not
  • Woken up after 5 minutes or 15 minutes

DV

  • Dreams recalled
  • Estimated length of dreaming
  • Eye movements
  • Dream content

Procedure

  • Each participant reported to lab just before bedtime
  • Were not allowed caffeine or alcohol
  • Electrodes were strapped to heads and faces
  • Slept alone in a dark room
  • EEG simultaneously recorded brain activity
  • Particpants were woken up by a doorbell and asked to recall their dream (if they had one) into a tape recorder
  • Participants that were in REM sleep were woken up after either 5 or 15 minutes and asked to state how long they were dreaming for
  • Partcipants were also woken up after one of four eye patterns movements were observed: Vertical, Horizontal, Vertical and Horizontal and Little or No Eye Movement 

Results

  • REM: Recall 152 VS No Recall 39
  • Non REM: Recall 11 VS No Recall 149
  • Participants on average correctly estimated how long they had been dreaming for
  • Strong association between dream content and pattern of eye movement eg. horizontal eye movement during a dream about watching two people throwing tomatoes at each other

Conclusion

  • REM is the time when we are most likely to dream
  • Dreams progress over time rather than happen simultaneously
  • The pattern of eye movement was related to the visual imagery of the dream
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Maguire et al (2000)

Aim

  • To find out if there are any changes in the structure of the brains of London taxi drivers due to their well-developed spatial navigation, especially in the hippocampus

Method

  • Quasi experiment
  • Independent Measures
  • Date collection through MRI scanners

IV

  • Whether the subject was a taxi driver or not
  • Time spent as a taxi driver

DV

  • VBM - identifies grey matter intensity in MRI scans
  • Pixel Counting - count of pixels within three regions of the hippocampus; body, anterior and posterior

Participants

  • Taxi drivers - 16 right-handed males, London taxi drivers, mean age of 44 years, all had been driving for 1 and a half years, all psychological and medically healthy
  • Control group - 50 right-handed males, non-taxi drivers, all psychologically and medically healthy

Procedure

  • Structural MRI scans were obtained

Results

  • There was significantly more grey matter volume found in the posterior hippocampus of the taxi drivers
  • However, there was more volume in the anterior hippocampus of the controls than the taxi drivers
  • Positive correlation was found in the volume of the posterior hippocampus and time spent as a taxi driver
  • Negative correlation was found in the volume of the anterior hippocampus and time spent as a taxi driver

Conclusions

  • Taxi drivers have a larger posterior hippocampus and a smaller anterior hippocampus
  • Correlation shows this is as a result of being a taxi driver, not a pre-existing structure which predisppses a person to become a taxi driver
  • Brain structures can change depending on input/function - brain plasticity
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Sperry (1968)

Aim

  • To study the psychological effects of brain hemisphere disconnection in order to understand the functions of the left and right hemispheres

Method

  • Quasi experiment

IV

  • Presence or absence of split-brain

DV

  • Naming of objects
  • Recognition of objects
  • Moving hands into positions
  • Drawing objects

Participants

  • 11 split-brain patients
  • All right handed
  • All advanced epileptics who didn't respond to drug therapy
  • All had received split-brain operation prior to experiment

Procedure

  • 1. Visual Task
  • 2. Tactile Task
  • 3. Visual and Tactile Task
  • 4. Test of the Right Hemisphere

1. Visual Task

  • Partcipants had images presented to both or one visual field and asked what they could see

2. Tactile Task

  • Verbal identification of objects placed into hands
  • Finding the object in a scrambled bag of objects

3. Visual and Tactile Task

  • An image of a hand with a black dot marked on it was presented to either RVF or LVF
  • The participant would then have to try and touch where the dot would be on their own hand
  • The left thumb would try and touch the same place on the left hand and the right thumb would try and touch the same place on the right hand

4. The Test of the Right Hemisphere

  • Geometric shapes were presented to both visual fields
  • In the middle of the presentation a nude image was flashed to the LVF only
  • The nude image would therefore only be seen by the right hemisphere
  • The participant was then asked if they had seen anything other than geometric shapes
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