Finished Chapter 5

• Quite an interesting chapter, where the author talks about blindspots in our eyes

• Our eyes have a blindspot which happens when we close one eye and are at specific distance from an object

  • The book has few examples to demonstrate that and it works

• This only happens when 1 eye is closed, because if both eyes are open, the other eyes seems to cover that blindspot, which is wonderful if you think about it.

• But the thing more wonderful is that, it is not exactly an “blind” spot, ie we dont see a black patch in front, but our brain is so capable that it fills it with the background of the surroundings

  • ie if you stare at a textured wall and there is a bottle in your blindspot — the brain will replace the bottle with the background texture of the wall
    • So basically you never realise that there is something in your blind spot
  • Author does few experiments in determining what and all can brain basically fill, this process is called “filling in”
    • It can fill in vertical line, vertical lines which dont align — surprisingly brain treats it as aligned when it is in blind spot, somewhat fills in shapes

• He mentions about two types of completion — perceptual and conceptual completion

  • Perceptual completion is fixed by the brain and cannot be altered — this is the completion which happens in the blindspot we have no control over it
  • Conceptual completion is basically our imagination — we can imagine a rabbit beside me, or a gorilla, or Chris Hemsworth.

• Also, one thing he mentions is that our brain is very good at filling things, if we think about a rabbit behind a fence, we dont think of a striped rabbit with fence covering its body, but infact we think about a whole rabbit with a fence in front, we can visualize things in 3 Dimensions

• With some experiments on patients having scotoma (partial loss of vision / blindspot)

  • There were people who were seeing still 2D cartoons in their scotoma
    • A good answer for this by author was that, as mentioned in previous chapter our brain has 2 pathways HOW (related to motion and space) and WHAT (colors and texture)
    • Maybe tha patients HOW pathway was blocked, coz of which they were only being able to render 2D drawings of cartoons with no depth and motion. Fascinating.
  • An experiment where he wrote 1,2,3 at the top and 7,8,9 at the bottom and placed is such that the patients scotoma, aligns the middle gap
    • The patient’s brain was able to fill those numbers in the middle but they were not real numbers, they were just things shaped as numbers and completely gibberish, like heiroglyphs (strange symbols)
      • His brain was rendering textures and colors but was not able to figure out what was it
  • Also in one experiment he was able to deduce, the brain first interprets bg texture, then colors and at end motion — which indicates there are specialized parts in brain to do different things.
  • Some were seeing animals, and vivid objects which they would have never seen before.
    • Which is again interesting because hallucinations usually happens from the things we see, and also is this similar to dreams? 🤔
  • And these kindof hallucinations happens a lot with elderly people with poor eyesight, etc. they can see things which didnt exist in real world
    • Which can also be the reason for people seeing UFOs and Ghosts 🤔