Why do we see this forward motion speed illusion by Akiyoshi Kitaoka?

You may not realize it, but I'm actually a professional illusionist. Not even joking! See TED talk at the end.

This video is an illusion by Akiyoshi Kitaoka.

The more he zooms in, the slower the train seems to be moving. It’s very effective!

Why does this happen?

Here’s what I wrote in a comment to him in February of 2020…

The illusion that speed decreases when zoomed is

because when one focuses on an inner portion of the movie, the optic flow angular speed is slow, and appears to fill one’s entitle visual field, which is consistent with overall lower forward speed.

Note: The more zoomed, the more densely packed the overhead rigging appears. So, even though you appear to be moving forward more slowly when zoomed in, the actual rate of rigging flowing by remains constant, consistent with same forward speed in all conditions.

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By the way, these optic flow dynamics undergird why we see hosts of illusions. The brain generates a perception of the anticipated next moment, thereby correcting for neural delay, as I discuss in this TED talk.

https://www.changizi.com/uploads/8/3/4/4/83445868/pp1.pdf

https://www.changizi.com/uploads/8/3/4/4/83445868/pp2.pdf

https://www.changizi.com/uploads/8/3/4/4/83445868/changizibrain25000chapter2.pdf

https://www.changizi.com/uploads/8/3/4/4/83445868/pp3.pdf

Finally, see Chapter 3 of my best seller, VISION REVOLUTION.