Interesting Discoveries About The Brain (4)

You see what you believe.  In their book, Sleights of Mind – What the Neuroscience of Magic Reveals about Our Everyday Deceptions, Dr. Susana Martinez-Conde and Dr. Stephen Macknik – both neuroscientists – investigate the manner in which quirks in our brain function can be used by magicians to both fool and entertain us –

The spooky truth is that your brain constructs reality, visual and otherwise.  What you see, hear, feel and think is based on what you expect to see, hear, feel and think.  In turn your expectations are based on all your prior experiences and memories. What you see in the here and now is what proved useful to you in the past.  You know that shadows fall a certain way, depending on time of day, that faces are normally viewed in an upright position, and that gravity exerts a predictable influence on all things…

The fact that consciousness feels like a solid, robust, fact-rich transcript of reality is just one of the illusions your brain creates for itself. (1) 

Explaining more about their research in an interview on the Brain Science Podcast, Dr. Martinez-Conde explains the difference between special effects – which are optical illusions – and visual illusions.

…optical illusions are things that happen because of the physical reality outside. For instance, if you take a pencil and stick it in a glass of water and it looks like it bends in the middle, it’s from the refractive index of the water vs. the air.  It’s an optical effect; it’s not something happening in our brain.  Even a camera would perceive it the same way…

…visual illusions are incredible percepts that happen that don’t match reality, that are due to the way our brain processes visual information.  And by extension then, cognitive illusions are those cognitive illusions that happen because of processing in the cognitive circuits of our brain. So, that’s really the different types of illusions that you can have.  And magicians use all of these all at once…(2)

All of which suggests that many of things we believe are really true in an objective sense, may, in fact, be just what we expect to be true.  Like the ball under the cup in a magician’s act.  Food for thought?


Photograph – Harry Houdini – 1910-1915 – Bain Collection, Library of Congress, USA.

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(1) Sleights of Mind – What the Neuroscience of Magic Reveals about Our Everyday Deceptions, Dr. Susana Martinez-Conde and Dr. Stephen Macknik.  Chapter 1.

(2) Brain Science Podcast interview with the authors here –  –


  1. Definitely food for thought!

    We see the world behind our eyes. We use our memories to quickly pre-judge people, places, and things based on earlier experiences.

    What we focus on grows larger, while the rest fades away to “white noise.”

    If we focus on the “negatives” (the things we don’t like about someone else, or the ways they’ve let us down), that perception shades our future dealings with them. Likewise with the “positives.”

    When we are in an upward spiral (falling in love) or a downward spiral (falling out of love) ~ it’s not always THEM that changed. Sometimes we’ve just realized that the image we created of THEM is inaccurate.

    As a result of our pre-judgments, we seldom see things as they are . . . we see things as we are.

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