Tuesday, May 31, 2011

Summer School - Psych 304 - Interesting Facts

On my last post about my summer course icey posted:
"post some things you've learned if that's legally ok please. behaviour is a very interesting topic."
I have decided to detail some of the interesting things I have learned thus far and don't worry icey, it is legal.

1. Eye Movement
How your brain interprets movement is quite extraordinary. Consider these four cases and try it out for yourself!
  1. Both object being viewed and eye are stationary. (Hold out a pencil, is it moving?)
    Result: Object appears to not be moving.
  2. Object is stationary but eye is moving. (Scan from the top to the bottom of the pencil, is it moving?)
    Result: Object appears to not be moving.
  3. Object is moving down but eye is stationary. (Move pencil downwards while keeping eye focused straight ahead, is it moving?)
    Result: Object appears to be moving.
Now here is where it gets a little bit complicated. Consider case two and three. In both of these the pencil changes its place on the back of the retina. When you move your eyes up the pencil but the pencil is stationary, the retinal image ends up hitting higher on the back of your eye. Yet the same thing occurs when the pencil moves down but your eye stays staring straight ahead (the focus ends up on the eraser in both cases). Why then does your brain interpret one of these as movement and the other as not movement. Well let us make a hypothesis and then test it. Perhaps when your brain moves your eye it subtracts this movement from the change in retinal image and so even though you move your eyes, your brain can tell the world is stationary. How then could we test this? Well try this:
  1. Stare off into the distance as far away as possible.
  2. Close your right eye.
  3. With your left finger gently push on your bottom eyelid to push your eye upwards.
  4. Continue to apply pressure, then release it in an alternating pattern.
  5. With enough pressure applied you should see the world tilt downwards!
It can be tricky to get this effect to work as people aren't usually comfortable with prodding their own eyeballs. I find that alternating pressure/no pressure helps you to better visualize the downward movement (it can be quite blurry). So what does this mean? Well you tilted your eyeball up, just like you did when you looked at the tip of the pencil. This time though, your brain did not initiate the movement of the eyeball so it was unable to subtract this movement, thus your brain said "The world is tilting down!".

I just realized this does not have much to do with behaviour so I will have to do another post tomorrow about behaviour. Dangit. Hope this is interesting icey!

25 comments:

  1. Luckily I wear contacts, so I have no problem touching my eyes.

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  2. it's damn interesting! and thank you for the shout out.
    after following steps 1-5 and actually holding it for some time i actually realized that (i believe my brain) got used to the fact that the world is suddenly slightly tilted ... kinda funny too.

    I'm definitely looking forward to your next post!
    cheers,
    -icey

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  3. This is WACK, please do keep coming up with this stuff lol!

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  4. Keep it up. I found that I knew the ones you were posting but I'd like to see other different ones.

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  5. Eww I cant touch my own eye! ^.^

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  6. very interesting. the brain is a mysterious thing.

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  7. Haha just for clarification you should be touching your eye THROUGH your bottom eyelid! No need to press your actual eye :S

    Also icey the reason your brain got used to it has to do with your reticular formation. Maybe I will do a post on that structure (it is really neat!).

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  8. haha, not a fan of poking my own eyeball so I dont think I'll be doing this

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  9. It's cool to see that you're so interested in the material, it must be a good course (and it sounds like you have a great instructor).

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  10. This is crazy! Perception is an interesting thing!

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  11. Really interesting. I like that you even included a do it yourself test! Awesome stuff.

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  12. wow, that's pretty interesting. My left eye feels funny now, but still interesting.

    I'm also interested in behavior, there was a PBS special about kids and sweets. They sat a kid at a table filled with candy, popcorn and the like. They ask the kid what he wants, but before giving it to him they leave the room for some made up reason. This leaves the kid alone with all the candy, however before actually leaving, the adults tell the kid that if they refrain from eating anything in their absence, they'll give him two of his choosing when they return.

    Turns out the kids who are not allowed to eat candy at home had no self control, they devoured everything. The kids who were allowed to eat candy at home just sat and waited the one or two minuets and were rewarded with twice what they were promised.

    I forgot what it was called, it dealt a lot with babies and kids. Very fascinating. Ooof, this is a long comment...

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  13. Yeah this is like the left side and the right side of the brain confusing each other isn't it?!

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  14. very interesting.good job on the blog.

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  15. Don't like touching my eye but this is very interesting!

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  16. Summer school sucks. You should be out chasing girls.

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  17. yeah, interesting things. I glued down my f5 key waiting for new content.

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  18. Very nice read. Please post more.

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  19. this post is ok, if you don't feel like posting tomorrow then wait for it :)

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  20. very interesting!
    keep it up!

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  21. i have definitely read about this before. itsamazing the different ticks we all have at a base level.
    follow ;)

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