psychology

The Height Illusions - 9/52

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I love optical illusions so I thought I would share a few of my favorite and with many people opting to take up 365 day challenges i thought i would try a 52 week challenge in which i will share with you a different Illusion every week. so if you have any you would like me to feature get in touch.

The Vertical-Horizontal Illusion (also known as the Bisection illusion) was created by Johann Joseph Oppel (1815 – 1894), a German mathematician and physicist. The Vertical-Horizontal Illusion was first published in the journal Jahresbericht des physikalischen Vereins zu Frankfurt am Main in 1855.

The vertical line appears longer than the horizontal line, even though both are of the same length.

It works the other way up too, and is sometimes called the T illusion.  It’s one of many illusions for which you’ll find a brilliant interactive demo on Michael Bach’s site.

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The top hat illusion and the famous arc in St. Louis, USA, are considered as variations of the vertical-horizontal illusion since the height of the hat or the arc has the exactly same length as their base

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The Cafe Wall Illusion 7/52

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The café wall illusion is a geometrical-optical illusion in which the parallel straight dividing lines between staggered rows with alternating black and white "bricks" appear to be sloped.

It was first described under the name Kindergarten illusion in 1898,[1] and re-discovered in 1973 by Richard Gregory.[2] According to Gregory, this effect was observed by a member of his laboratory, Steve Simpson, in the tiles of the wall of a café at the bottom of St Michael's Hill, Bristol. It is a variant of the shifted-chessboard illusion originated by Hugo Münsterberg.[3]

The precise cause of the illusion is not well understood, although it appears to involve interactions between the neurons in the visual cortex which code for orientation. It is unclear whether some inhibitory mechanism is at play, or if there is a kind of computational filter acting on input from cells operating at different spatial frequencies, i.e. taking their inputs from larger or smaller areas of the visual field (Takeuchi 2005).

Philosophers have also been interested in what illusions like this illusion can tell us about the nature of experience. For example, in the case of experiencing the Café Wall Illusion, it would seem to be that the one can know that the lines are parallel whilst at the same time one experiences them as unparallel. If so, then this might count against the claim the perceptual states are belief-like, because if perceptual states were belief like then, when experiencing the Café Wall Illusion one would simultaneously believe that the lines were, and were not, parallel. This would seem to entail that one was being irrational, because one would simultaneously be holding contradictory beliefs. But it seems highly implausible that one is being irrational when under going this illusion. For discussion of this general point about whether perceptions are like beliefs, see Crane & French (2016).

 
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The Orbison Illusion 6/52

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The Orbison Illusion 6/52

I love optical illusions so I thought I would share a few of my favorite and with many people opting to take up 365 day challenges i thought i would try a 52 week challenge in which i will share with you a different Illusion every week. so if you have any you would like me to feature get in touch.

The Orbison Illusion was created by William Orbison (1912 - 1952), an American psychologist. Orbison first published the illusion in the American Journal of Psychology, in 1939. 

The Orbison Illusion is one among a number of illusions where a central aspect of a simple line image – e.g. the length, straightness, or parallelism of lines – appears distorted by other aspects of the image – e.g. other background/foreground lines, or other intersecting shapes. These are sometimes called ‘geometrical optical illusions’.

What are the best optical illusions you've found on the web? Do you have more amazing examples you don't see here?

Share your thoughts with us in the comments section below.

The Troxler effect 5/52

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I love optical illusions so I thought I would share a few of my favorite and with many people opting to take up 365 day challenges i thought i would try a 52 week challenge in which i will share with you a different Illusion every week. so if you have any you would like me to feature get in touch.

The Troxler Effect Week 5

If you focus on one tiny point, and the rest of the scene doesn't move, your eyes sort of become desensitised to it, and fade it into the background.

It's called the Troxler effect, or Troxler flading - named for physician Ignaz Paul Vital Troxler, who discovered in 1804 that if he focussed his eyes on a fixed spot, the surrounding image would gradually disappear from view.

So now you know something about the way your brain can lie to you about the information right in front of your eyes. We think there's a life lesson somewhere in there for all of us.

The Troxler Effect is named after Swiss physician and philosopher Ignaz Paul Vital Troxler (1780-1866).

What are the best optical illusions you've found on the web? Do you have more amazing examples you don't see here?

Share your thoughts with us in the comments section below.