Which One Is Larger – Jastrow Illusion

These days you can’t trust anyone, anymore. This one is called Jastrow illusion. It is an optical illusion discovered by the American psychologist Joseph Jastrow in 1889. Oh, how sure I was that this illusion wasn’t possible, and only another hoax, but after I watched the video I was convinced it’s true. Amazing! As you see these two objects, even though appear different in sizes, they are actually exactly the same! I posted simmilar illusion previously, but now I obtained the video to convince you! Click on the image below to see the video. The video was shot in Hong Kong’s Museum of Science.

32 Replies to “Which One Is Larger – Jastrow Illusion”

  1. Your original post is a real illusion and worth thinking about.

    This video is just a play with the camera lenses – the nearest object looks bigger than the one far away, and thus there’s nothing special on it.

  2. This is a very simple illusion you don’t even need to watch the video….

    The 2 figures here are Trapezoids and they are obviously the same size. They both have one big side and one small side, and in this picture they are matching the small side from the top figure with the big side from the bottom picture and taking the photograph from an angle were it’s not so obvious, but you can still crearly see that the figure on top has its big side sticking out more to the left than the one in the bottom…

    If you were to set both figures with theirbig sides matching, you would crearly see that they are the same size.

  3. um i dont know what slavco means, cause trapezoids are not curved, and there is a chance that the shpaes have different size sides, but to me, it looks like the yellow one is simply further away then the orange one, because of the solid backround you almost can’t tell. however there is some overlap, the red being “on top” of the yellow. however that is just my opinion

  4. I click on the link and it takes me to a video with an alien in it. It does not look like the right video. That is a bummer.

  5. Mike, all fine and well correcting people on their geometrical terms, but it is VERY clear that you didnĀ“t even take the time to watch the video.
    The perspex pieces DO NOT overlap one another.


  6. well… im thinking they are playing with the lenses. i also think that when the dude took away the red peice, he switched it, and when he mtched them up on each other he obviously took a peice away, but playing with the lenses made it seem it wasnt a sepret part. it might be wrong, but thats what i think.

  7. wait, its so simple. they are the same size. the top part is bigger and small part is smaller. look it up on google, look for 2 blue blocks… you will understand that this is a raelly dumb illusion.

  8. This is the dumbest illusion i’ve seen tbh.
    The one on the bottoms the closest to the lense so obviously it’ll be bigger but they are really the same size.(Nothing to do with playing with the lense.)Noobs.

  9. I think its the fact that the side are slanted in giving the shapes a curved rhombus look but the in the picture they seem to be different degree angles and the fact that the bottom curve is the exact degree of the top thus making the shapes seem different sizes when put in those positions if you draw it your self on graph paper you will be able to see it makes perfect sense…yes? no? maybe?

  10. Slavco explained this perfectly, I happen to teach science and we have used this same example to teach perspective.
    To Mike, regarding the trapezoid ‘correction’, trapezoids only require parallel sides, they don’t have to be straight.
    And as for everyone who feels the need to call every illusion ‘dumb’ please just shut up. If the only thing that you have to offer on the forum is “thats dumb” then just don’t post, no one cares to read such a useless statement anyway.

  11. Coolez, we don’t know, and really don’t care. But they are the same size. Practically, I think it’s the curve in the polygonal shapes that makes it look that way. If they put the shapes on top of each other the way they did it at 0:04 and 0:12, and they looked the same length, then put them on top of each other the way they did at 0:17, then one would be longer than the other. I understand if you don’t get my point. But the shadow is kind of obvious that they don’t switch the blocks.

  12. i think the illusion is actually the table the blocks are on…i believe the table curves upwards and outwards near the camera lens, creating the illusion that the pieces are different sizes.

  13. it’s just because the bottom of the blocks are smaller than the top, no matter what angle you look at them it still appears that way! my 7th grade science teacher showed my class this once.

  14. I can’t believe those who can’t believe the pieces are the same size! Just pick two sheets of paper over each other, and with a treasure cut a curved shape like in the video. You can paint them with distinctive colours but it is not necessary (or just turn over one of them if the paper was obtained from a magazine with colourful pages). Can you see it now?

  15. Actually my guidance counselor in 5th grade showed us this and explained it. If you look closely, the tops of those are wider than the bottoms, hence the illusion. It isn’t very noticeable but once you know, you will always spot it.

  16. well then how do you explain this

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