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THE BIOLOGICAL APPROACH IN PSYCHOLOGY

THE BIOLOGICAL APPROACH IN PSYCHOLOGY. The Biological Approach 1. Sometimes called BIO-PSYCHOLOGY Or Physiological Approach How does your body influence your thoughts and behaviour? EG alcohol or drugs Genes & DNA Inherited… innate Nature, not nurture. The Biological Approach 2.

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THE BIOLOGICAL APPROACH IN PSYCHOLOGY

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  1. THE BIOLOGICAL APPROACH IN PSYCHOLOGY

  2. The Biological Approach 1 • Sometimes called BIO-PSYCHOLOGY • Or Physiological Approach • How does your body influence your thoughts and behaviour? • EG alcohol or drugs • Genes & DNA • Inherited… innate • Nature, not nurture

  3. The Biological Approach 2 • Structure of the brain • Extreme view: thinking just _is_ changes going on in the brain • Hormones • Assumption: human behaviour is dictated by biological processes • DETERMINIST? • “One day, all psychology will be bio-psychology”

  4. The Case of Phineas Gage • 1848, railroad worker, dynamite accident • Iron bar through his skull – but survived • Personality was transformed • Before accident: efficient foreman, well-balanced mind • Now: aggressive and obscene, no respect for workmates, patience or ability to plan for future • Friends: “He was no longer Gage” • Became an aimless drifter • Skull preserved • Damage to prefrontal cortex = moral decision-making

  5. The Hippocampus of H.M. • H.M. suffered from lifelong epilsepsy • William Scoville carried out brain surgery on him • Removed part of hippocampus • Epilepsy reduced • Lost all memories of last 10 years! • Lost ability to store new memories! • Memory span of a few minutes • Became guinea pig for psychologists… • … but never realised it!

  6. Brain scanning • Study the brain without cutting it open • View the brain while it’s working • Identify brain functions – what parts of the brain do what • EG the hippocampus and memory • EG the prefrontal lobe and moral thought

  7. CAT Scans • Computerised Axial Tomography • Take a series of X-Rays 180 degrees round the head • Shows areas of damage • EG good for spotting strokes

  8. MRI Scans • Magnetic Resonance Imaging • Tube-like machine • Powerful magnetic field • Brain atoms change their spin • Detector picks up brain’s radio signals • Computer builds map of brain’s structure

  9. PET Scans • Positron Emission Tomography • Injected with slightly radioactive glucose chemical • Radiation sensors track the radioactive blood moving through the brain • Takes 10-40 minutes • Your brain is radioactive!

  10. Brain scanning 2 • Brain scans show coloured picture of brain • “Hot” areas (red) are busy • “Cold” areas (green/blue) are less active • Shows parts of the brain are active… NOT what it is they are doing

  11. CORE STUDY: MAGUIRE (2000) • Eleanor Maguire tested London cabbies • Used MRI scanning • Focus on hippocampus  spatial memory • Hippocampus same size for taxi drivers and control group… but… • Cabbies had larger posterior (rear) hippocampus, smaller anterior (front) • Correlation over time spent driving!

  12. What about sleep? • The brain does not “shut down” during sleep • Brain activity MORE varied than when awake • What happens when we dream? • Is this related to brain activity too?

  13. Stages of Sleep • AWAKE – brainwaves are beta waves • RELAXED (eg meditating) – slower, regular waves – alpha waves • STAGE 1 and 2 SLEEP – slower theta waves • Very light sleep, easily woken • STAGE 3 and 4 – slowest delta waves • Very hard to wake • Sleepwalking/talking

  14. The EEG • Electro encephalo gram • Device for measuring brainwaves • Electrodes attach to scalp • Bulky and uncomfortable • Similar devices can measure muscle tension (EMG) • And eye movements (EOG) • Why measure eye movements?

  15. REM sleep • RAPID EYE MOVEMENT • Eyes start to dart about (measure with EOG) • Muscles go limp (EMG) • Strange brainwaves – fast and irregular – similar to awake (EEG) • During a night we go through cycles • 1 through 4 (deep sleep) • Then back to 3, then 2… • But then REM instead of stage 1 • Takes about 90 minutes • Several cycles per night • REM gets longer each time, stage 4 gets shorter

  16. CORE STUDY: DEMENT & KLEITMAN (1957) • Is REM the same as dreaming? • Participants in sleep lab, wired up to EEG and EOG • Woken by bell, describe dream into mic • Usually, dreams recalled if woken from REM sleep • Also, eye movements match dream content (watching tennis = side to side) • Also, dreams appear to last as long as REM

  17. One brain or two? • The brain is SYMMETRICAL • Looked at from on top, it’s made of two halves • Called HEMISPHERES • Linked by a “bridge” of nerve fibres • The CORPUS CALLOSUM • Do the hemispheres do different jobs?

  18. Lateralisation of brain function • Left hemisphere controls right eye, right arm • (…but left nostril… weird) • Right hemisphere controls left eye & arm (but right nostril…) • Normally this is OK, because hemispheres “talk to each other” through the corpus callosum • What if there was no corpus callosum?

  19. Commissurotomy • In some cases of severe epilepsy, brain surgery is done (eg H.M.) • Severing the corpus callosum • Creates a person with TWO BRAINS • No apparent big side-effects • Some difficulties with long term planning • Some inappropriate emotions • NB animals suffer behavioural problems after this surgery

  20. CORE STUDY: SPERRY (1968) • Roger Sperry is a Nobel Prize winning neurobiologist • Split-brain patients to test – all had the operation due to epilepsy • Device flashed images on screen to left or right eye • Asked to pick up or name object shown • Seen by left eye  couldn’t name it • Seen by right eye  couldn’t point to it with right hand • Each hemisphere has separate consciousness!

  21. Macbeth: free-will? Minority Report DETERMINISM • Do we have free will or is everything determined for us? • Determinism = things beyond our control determine everything we think and do • Our upbringing (Freud)… our social situation (Behaviourism)… our biology • But we seem to make choices – doesn’t determinism deny our daily experience?

  22. Or no brain at all? • Research by John Lorber • Sheffield student went for routine CAT scan • He had almost no brain • Spinal fluid filled inside of skull, squashing brain round the sides • IQ of 126 (above average) • Went on to get degree in Mathematics • So, who needs a brain?

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