Which Orientation Does Your Brain Prefer, Horizontal or Vertical?

Peter Tse from Dartmouth College (USA) has re-invented the classic afterimage optical illusion. If you haven’t encountered afterimage illusions before, I strongly recommend visiting #Afterimages category before reading through rest of this entry. So why is this illusion different? By using it, you can reveal if your brain predominantly sees horizontal or vertical lines! To begin, you’ll need to fixate the colored image (one on your left) by looking at the fixation spot for about 60 seconds. Now shift your eyes to the fixation spot surrounded by rectangular outlines. Which afterimage did you see first? You can manually shift which afterimage you experience by attending to one rectangle and then the other. If you attend to the vertical outline rectangle you will see the afterimage corresponding to it, and if you attend to the horizontal outline rectangle you will see the different afterimage corresponding to it. Now wasn’t this great?!

99 Replies to “Which Orientation Does Your Brain Prefer, Horizontal or Vertical?”

  1. I saw the vertical one first. The stripes look pink and white. The horizontal one just looked like a dark shade of gray to my eyes. I couldn’t see the stripes horizontally.

  2. Very interesting! It was HARD to concentrate on the dot for 60 secs, it kept trying to change the colours I was looking at. Then, when I did transfer to the other blank rectangels, they were slightly diagonal, not in the same horizontal and vertical directions. I also found that when I blinked, the other orientation came into view. But I started with the horizontal only.

    1. Same here too. But I saw the vertical ones first. It was only after 10 seconds or so that I could see both vertical and horizontal images at the same time!

  3. i saw horizantal first… but couldn’t the lightness of the blue and yellow and the darkness of the green and black effect this?

  4. I think you instead get the darkest (vertical) lines first in the after image. If the image is rotated 90 degrees don’t the same lines (the darker) appear first?

    1. I actually turned my laptop sideways to see if the color rather than the direction of the lines was what made me see the lines vertical or horizontal. My brain picked up he black lines (which turned to pink/ white) both times! Vertical to start, then horizontal (when the sideways laptop rendered them so). I’m not sure what this expirement actually proves, but it is interesting that everyone sees it differently!

  5. That’s all fine and good (horizonal/vertical illusion) but what does it mean (orientation). Just knowing which your brain prefers isn’t enough, there has to be a reason (no matter how mundane) therefore, a hint as to what it all means scientifically or otherwise should be explained otherwise it’s really useless as far as curiousity is concerned.

  6. I LOVE THIS ONE, first i saw horizontal, but then i could see vertical tooo, and i can switch between them… this is AWESOME!!!!!!!!!!!!!!!§

  7. Nice but isn’t this a bit of a fluke? There are many aspects that affect this such that it is no longer an honest optical illusion. 1st: Human vision is slightly more horizontal than vertical (both eyes cover a circle). Second:there are colours that might affect your preference. Third, the horizontal lines are on top of the vertical lines. 1 and 3 will render a preference to horizontal whereas it is known we actually do prefer vertical since from an evolutionary point of view, vertical objects are of greater importance. I think to get a more honest idea you should also check this with a 90 degrees turned picture.

    1. ironarjen – good point – I turned the illusion sideways – I get dark blue vertically. I got the same dark blue horizontally as presented. The color is dominant over any vertical or horizontal bias.

  8. Cool. At first I saw the vertical bars, then was able to “shift” to the horizontal bars and then back and forth before the effect wore off. At one point I was able to see both in the after image.

  9. Vertical first then horizontal.

    Interestingly, before even getting to the after-image, I began to see the pattern as columns of three dimensional ridges. Initially the “shadowed” side was on the left, but with some coaxing. I could shift the ridge tops over so the shadow was on the right (as if the light source switched).

    With a little more effort, I could switch to horizontal rows of ridges.

    My guess is that which ever way you view the ridges is the way you will view the after-image. That was my experience. And,if I alternated rapidly between vertical and horizontal ridges on the right, I ended up with a checker board after-image.

    This is an excellent, multilayer-ed illusion.

  10. not sure what is supposed to happen here. I see the checkered aftermath illusion, not necissarily one or the other. I see both just as the colored image is. I can then force myself to see one, but i see both if i stare at the dots, moving my eyes to a direction cause only one image to appear. Poor illusion. Im pretty disapointed in the last few weeks illusions.

  11. Alright, I see the horizontal lines first and the vertical followed when I concentrated on that box. But…..what does it mean??

  12. I think it has more to do with the colors, because when I did it the first time I saw the vertical image, then I turned my head sideways and did it again that time I saw the horizotal image.

  13. Horizontal for me to start with, flipping between them was relatively easy.

    The flashing advert started to get annoying whilst looking for 60 seconds :)

    1. I originally saw horizontal, then each time I blinked it switched between vertical and horizontal again. After about 10 blinks, I saw both interlayered at a slightly skewed angle (with the top of the verticals leaning to the right) – haha maybe I stared for too long.

  14. I saw horizontal, then I blinked and it was vertical, and then I blinked and it was horizontal again. After I think 5 blinks it stayed horizontal.

  15. I wonder if the colors have anything to do with what you see first… I saw the horizontal first, but I wonder if I would see the vertical first if the colors were switched (if the horizontal stripes were black and green and the vertical stripes were blue and yellow).

  16. This is one of the best one’s on here! I saw vertical first but was able to shift and see either one at a time! Really concentrate and focus on the white dot for 30 seconds!

  17. WHOOAA! At first I see horizontal and if I blink I see vertical and I blink again and see horizontal and soo on, until the image fades from my eyes! :DDD AMAZING!!!

  18. Well, if I blink alot I see the vertical, THEN if I blink again some more,I see horizontal, but I think the one that stood out the most was the vertical.

  19. I found that I can’t see the lines unless I blink rapidly and in doing so I found that If you blink hard you see the Vertical lines but if you blink not so hard you see the horizontal lines…

    Hope this helped

  20. I saw vertical first. Then I turned the image 90 degrees, still saw vertical lines, but different color. Then i turned the original image 45 degrees, I saw all the lines diagonally.

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