9 thoughts on “Optical illusions—one with a cat”

  3. Really cool. I wonder if the cat would have been as interested in the non-cat illusions.

  4. Does anyone know if that is technically an illusion (in terms of processing in the nervous system) or just how the light refracts?

    1. Good point. I don’t think it’s an illusion as such. Simply the bars of the two slightly differently-spaced grids (as I presume) alternatively adding locally to give solid black, and not-adding. No different in principle from the little pixel dots on my screen adding to give ‘solid’ lines and patches of colour.

    2. The illusion is very simple. The vertical bars leave only parts of the picture visible, and the way the bars are spaced is matched with which parts of the picture correspond to which frame of the animation – as such, is much like a flip book, the movement of the vertical bars corresponding to turning pages.

      The only illusion which remains is how we can see a coherent picture when nine tenths of it is obstructed by the vertical bars. This is a product of how the brain fills in and assumes, which should be familiar from a number of other optical illusions, or for that matter your own blind spot, though it is fascinating that you can get a reasonably high number of frames from a single sheet of paper, because the brain doesn’t mind filling in a lot of guessing from very little signal.

      1. This perfectly illustrates why science and religion are not compatible!

        Religion is based on delusions of the human brain which are filling in the gaps, based on ‘very little signal’ and ‘a lot of guessing’ (even erroneous signals, as in false indoctrination or traditions, etc.). In science, scientists are expected, and generally go to the nth degree, to use intellectual integrity, rational thinking and the scientific method to fill in the gaps.

  5. I wonder how I would feel about these illusions if the music consisted of slide-whistles and kazoos. Cool stuff, but the music tried to infuse a sense of the magisterial that more befits time-lapse metamorphosis or a cheetah sprinting, not B&W lines on a page.

    The Science and Industry museum in Chicago used to have these as an exhibit in the 70s (perhaps they still do). They had big slotted wheels that you could turn to see similar “animations.”

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