Mental Construction of Reality


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ToK Lesson on Sense Perception, focussing on menatl construction of reality and nature of eye witness testimony

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Mental Construction of Reality

  1. 1. The mental construction of reality What is the link between perception and reality?
  2. 2. Hermann Grid Where are the grey dots? Not on the paper, so where?
  3. 3. What do you see? Where are these ‘non-existent’ shapes?
  4. 4. What is going on? sense data sense data Brain works out what is the best story it can tell your mind based on the sense data
  5. 5. What ‘story’ is your brain telling you? that the central area is curved, three dimensional?
  6. 6. What story is your brain telling you? that the image is three dimensional?
  7. 7. What is the real pattern here? Does your brain ‘flip’ between the diamonds and the rectilinear pattern?
  8. 8. Imagine <ul><li>How can this be as you could not hear the conversations? </li></ul><ul><li>What does this suggest about the way our brains work? </li></ul>You are in a noisy room with lots of people talking, including yourself. You can’t hear the other conversations, but suddenly you hear your name mentioned across the room.
  9. 9. <ul><li>Why do we not see small dark spots there? </li></ul><ul><li>What does this suggest about the way our brains work? </li></ul>In each eye there is a blind spot. The blind spot is a small area near the centre of the visual field where the optic nerve leaves the eye to go to the brain. There are no light receptors in this small area (hence the name blind spot).
  10. 10. <ul><li>How can this be? </li></ul><ul><li>What does it suggest about the way our brains work? </li></ul>Professional tea tasters can distinguish between literally thousands of brands of tea. Wine tasters can tell you the grape, year, country, region, vineyard and even which side of the valley a particular bottle of wine has come from. But these professionals have no more taste buds than you or I do. They have no more nerves in their tongues, and those they do have are not any more sensitive than the norm.
  11. 11. Upside-down glasses <ul><li>What happens when you wear upside-down glasses? </li></ul><ul><li>At first? </li></ul><ul><li>After some time? </li></ul>
  12. 12. The mental construction of reality <ul><li>Previous Experience </li></ul><ul><li>Reason </li></ul><ul><li>Expectation </li></ul><ul><li>Emotion </li></ul><ul><li>Preconceived ideas </li></ul>If the brain has to make sense of the sensory data, what does it use to make sense of this?
  13. 13. Should we trust eye-witnesses?
  14. 14. Case of Ronald Cotton 13 mins
  15. 15. How accurate are memories? 2 mins 2 mins 2 mins Bugs Bunny Effect
  16. 16. The Case of Jean Charles de Menezes, killed at Stockwell Tube, July 2005 <ul><li>Eyewitnesses said </li></ul><ul><li>Dressed in &quot;baseball cap, blue fleece and baggy trousers.“ </li></ul><ul><li>wearing a large winter coat, which &quot;looked out of place“ in summer. </li></ul><ul><li>wearing a &quot;bomb belt with wires coming out.“ </li></ul><ul><li>jumped over the ticket barrier, ran down an escalator and tried to jump on to a train. </li></ul><ul><li>In fact </li></ul><ul><li>Dressed in jeans and light denim jacket, no tool bag or bomb belt </li></ul><ul><li>Used his Oyster card to get through barrier, did not jump over it or run </li></ul>
  17. 17. The Case of Jean Charles de Menezes, killed at Stockwell Tube, July 2005 <ul><li>Eyewitnesses said </li></ul><ul><li>Five shots heard </li></ul><ul><li>Three shots heard </li></ul><ul><li>Police challenged JCM but he refused to obey instructions </li></ul><ul><li>Police shouted “Everybody Out!” </li></ul><ul><li>In fact </li></ul><ul><li>Police issued no warning or instructions </li></ul><ul><li>Police had been following JCM for about an hour as he travelled from home on foot and bus to Stockwell </li></ul><ul><li>was already on the ground, several police officers piled on top of him when shot </li></ul><ul><li>Eight shots, 7 to head 1 to shoulder </li></ul>
  18. 18. This lesson <ul><li>The mental construction of reality </li></ul><ul><li>Should we trust eye-witnesses? </li></ul><ul><li>How is this relevant to us? </li></ul><ul><li>Confirmation Bias </li></ul><ul><li>Coherence test </li></ul>
  19. 19. Homework <ul><li>Read chapter 4 of text book </li></ul><ul><li>Read “Two fish swimming along” by David Foster Wallace </li></ul><ul><ul><li>What are its main points about perception and knowledge of the world? </li></ul></ul>
  20. 20. <ul><li>Once Zhuangzi dreamt he was a butterfly, a butterfly flitting and fluttering around, happy with himself and doing as he pleased. He didn't know he was Zhuangzi. Suddenly he woke up and there he was, solid and unmistakable Zhuangzi. But he didn't know if he was Zhuangzi who had dreamt he was a butterfly, or a butterfly dreaming he was Zhuangzi. </li></ul>
  21. 21. Brain in a vat?