Schizophrenics 1, Hollow Mask 0

2 comments April 7th, 2009at 08:34pm Posted by Eli

It’s ironic that at least in this one small way, schizophrenics have a firmer grasp on reality than the rest of us.

Schizophrenia sufferers aren’t fooled by an optical illusion known as the “hollow mask” that the rest of us fall for because connections between the sensory and conceptual areas of their brains might be on the fritz.

In the hollow mask illusion, viewers perceive a concave face (like the back side of a hollow mask) as a normal convex face. The illusion exploits our brain’s strategy for making sense of the visual world: uniting what it actually sees — known as bottom-up processing — with what it expects to see based on prior experience — known as top-down processing.


This powerful expectation overrides visual cues, like shadows and depth information, that indicate anything to the contrary.

But patients with schizophrenia are undeterred by implausibility: They see the hollow face for what it is…. Some psychologists believe [their] dissociation from reality may result from an imbalance between bottom-up and top-down processing — a hypothesis ripe for testing using the hollow mask illusion.


When healthy subjects looked at the concave faces, connections strengthened between the frontoparietal network, which is involved in top-down processing, and the visual areas of the brain that receive information from the eyes. In patients with schizophrenia, no such strengthening occurred.

Dima thinks when healthy subjects see the illusion, which is somewhat ambiguous, their brains strengthen this connection such that what they expect — a normal face — becomes more influential, overpowering the actual, though unlikely, visual information. Schizophrenia patients, meanwhile, may be unable to modulate this pathway, accepting the concave face as reality.

It makes sense.  The brain uses all kinds of behind-the-scenes processing and shortcuts to (usually) simplify and manage our perceptions – anyone whose brain is unable to do that is necessarily going to experience the world in a very different way.  In some cases malfunctioning filters might make someone more perceptive, but it’s more likely that they’ll be flooded and overwhelmed (the filters are there for a reason, after all).  This was actually the explanation for the Joker’s insanity in the Arkham Asylum graphic novel: He’s mad because he perceives everything.

Entry Filed under: Coolness,Science,Weirdness


  • 1. Ol'Froth  |  April 8th, 2009 at 8:12 pm

    Well! That clears something up. Whenever I view satelite images of craters, they look to me as if they are rising up, like a pimple, instead of a depression.

    That, or I’m just f’d up.

  • 2. ::matthew  |  April 8th, 2009 at 10:43 pm

    the video on the link is hella cool. One psychological diagnosis down…

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