Mind Hacks: Familiar faces in unfamiliar places

by Stephanie Chasteen on May 9, 2011

As part of this mini series of cool tricks about the brain (from Mind Hacks), I wanted to write about one neat little trick that I use in a lot of my talks.  It wakes people up.  And the kind of delight that occurs from this simple little Hack makes an audience warm up to you.  Try it sometime.

Here’s the hack.  Look at this picture:

Now scroll to the bottom of this post to see that image right-side up.

Surprised?  We process faces differently from other objects.  If this were just, say, the picture of some buildings, we might have been able to figure out what was wrong.  But we process faces differently from other types of things.  Faces are special, important — being able to recognize who’s been nice to us in the past and who snubs us is important for more than just navigating a party; in times past, that could help us survive by avoiding enemies or recognizing our mates.  And it’s amazing to me how easy it is for us to distinguish between faces.  Once I recognized my housemate from a fleeting glance of his eyes, through his motorcycle helmet, as he was moving, a half a block away.  Astounding.  But even for those of us who have trouble putting faces to names, or knowing when we’ve met someone before, it’s pretty easy (except in some rare cases), to distinguish one person from the other, despite the fact that we all have pretty much the same basic features.  Interesting tidbit:  When I was in Peace Corps in Guinea in West Africa, I had trouble telling people apart from one another — all the normal cues such as hair and eye color were gone, and replaced with cues that I wasn’t used to using, such as skin tone, flatness of the nose, or shape of eyes.  But what surprised me was that they had trouble distinguishing me from my predecessor — even though I am small, with short dark hair and brown eyes, and she had long blond hair and blue eyes.  But confusion works on both sides of the fence; what distinguished me from the previous volunteer were things that they were also not used to using as visual cues.   When I pointed out the hair color difference, they argued that hair color was mutable — that it could change, that’s not a feature you use to identify someone.  (Apparently the big distinguishing feature that they used was our butts — mine was small and hers, well, I guess was a bit of a wider load.   Funny.)

So, why do we not notice that the photo above is strange?  We process faces as a whole (as a gestalt), not as individual pieces.  And we’re used to seeing faces right side up.  Once it’s turned upside down, that holistic processing gets disrupted, so we try to put the face together from the individual features.  According to the book, “this makes it much harder to detect that something is ‘wrong’ than when we are able to use holistic processing”.

There is an Exploratorium snack on this, called Vanna (because the upside down face in the museum exhibit is of Vanna White), but I always found the explanation a bit wanting.

I use this set of images in presentations — showing first the upside down face (but not for too long), while talking about something vague about how we use familiar things to learn.  Then I show the right side up version, and everybody gasps and laughs.  (People usually ask me to switch between the two a few times, so I have a slide where they’re displayed side by side).  You can use this in lots of places — if you’re talking about perception and how the brain tricks us.  If you’re talking about learning, and how it’s important to start with something familiar, or to scaffold student understanding from the simple to the complex.  I often say that you need to start with the equivalent of the right side up, not modified face, in the class.  Move to the right side up, modified face.  And then to the upside down modified face.  This is a nice visual representation of scaffolding of complex ideas to reach something unfamiliar and strange.

Here is the right-side up image.


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