14 March 2011

Change blindness

To quote my favorite T-shirt:  Stand back!  I’m going to try Science!

I am a neuroscientist by trade, and I can get quite passionate about it.  So you should expect to learn some brain stuff on this blog.  And change blindness is maybe the coolest brain phenomenon ever.  I’ll probably take that back tomorrow.

Before you go look up what I’m talking about, please view this YouTube video.  This is direct from a scientific study, and I want you to take this test.  There’s kind of a lot going on all at once so be sure to really focus, okay?  Go take the test and come back.

I assume you have taken the test and seen the thing.  You know what thing I’m talking about. 

So see, here’s the thing about brains.  You miss a lot of what’s going on in your world.  Like really big things.  Like obvious things.  Like when I hear of a bicyclist wearing all neon colors with blinking lights and flags on still getting hit by a car, I’m frankly not surprised. 

Yes, I think we all kind of knew we didn’t notice everything in our worlds around us.  But change blindness is funny.  Check out this video about people asking directions.

50%!!!  Almost fifty full percent of people giving directions to a stranger didn’t notice that the stranger was an entirely different person after only a few brief seconds of interruption!  This finding has been demonstrated many, many times since and in many ways.  You can even change the gender or the race of the experimenter and still people won’t notice (okay, it’s a smaller proportion of people not noticing, but still). 

The key ingredient in this experiment, obviously, is that your attention’s diverted in giving directions.  You’re allocating less attention to things like who’s doing the asking, and that’s how you start missing things like gender and race.  And how you stop looking for gorillas and other anomalies.  You hit a bicyclist because you’re really, really concerned about whether you have enough milk in the fridge at home.

But change blindness isn’t always about attention.  You can be dead focused on trying to find a change in a scene and it can still take you forever to finally see it.  I’ll direct you to one more site where you can spend all the time you want trying to find the changes happening between scenes:

I really like the ones under the heading What’s the Difference between Looking and Seeing?” – like the airplane or the sailboats.  In these you’re trying to find the bit of the picture that’s different from frame to frame, like you used to do with Highlights magazine at the pediatrician’s office.  These are supposed to show you that you can be looking for that bicyclist and still miss him.

So your brain’s not all you thought it was, is it?  Don’t get discouraged.  This is your brain doing what it does best: filtering an overwhelming morass of information into a digestible, interpretable package.  It does a phenomenally amazing job at sensing and understanding the world, all things considered, and in light of that you can forgive it its minor slipups.  Keep in mind that these tests are designed to reliably tax your attentional abilities to their very limits. 

And good for you, all those of you who saw the gorilla – but don’t get too cocky.  It’s not that 50% of people are just bad at seeing these things, only that 50% of people got caught up this time.  If you give people lots of these tests, eventually everyone misses some.

I should have warned you this was the post where I was going to talk about gorillas you can’t see.  Sorry.

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