• Question: how do optical illusions work?

    Asked by maevelewisxo to Damien, Rachael, Simon, Suzi, Tim on 20 Jun 2011. This question was also asked by oliviaeganx, lucysmith, chloetaylorx, morgansheridan, kaboom2.
    • Photo: Suzi Gage

      Suzi Gage answered on 20 Jun 2011:

      Hi everyone!
      Great question!
      When I studied psychology optical illusions were one of my favourite parts of it!
      Different ones can operate in different ways. Some are to do with the way our eyes work, and some the way our brains work.

      Some illusions show you a lot of movement one way, and then a static (non moving) object, which will look like it’s moving the other way. When you’re looking at the moving object, certain neurons in the ‘detect movement’ area of the brain will fire. These neurons get tired, and so when the object stops moving, they need a while to recover. A still object normally causes both ‘up’ and ‘down’ neurons to fire, so if the ‘down’ neurons are recovering, only the ‘up’ ones will fire, making it seem as if the object is moving up.

      Hope this answers your question – let me know if you’d like more info.

      What’s your favourite optical illusion?

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