Illusions Fool Adults, But Not Kids

realtive sizes optical illusion - aI have prepared a little longer article than usual for today, but if you have nerves going through it (specially if you are a kid or have one), I believe you will learn something worth knowing. So let’s begin – take a cup of coffee, sit back in your favorite easy chair and we are ready to start…

Point of this post is to explain how sometimes seeing means deceiving before believing, depending on your age. There is a new study suggesting that children and adults size up objects differently, giving youngsters protection against a visual illusion that bedevils their elders. This unusual triumph of kids over grown-ups suggests that the brain’s capacity to consider the context of visual scenes, and not just focus on parts of scenes, develops slowly. Even at age 10, children lack adults’ attunement to visual context. Paper suggesting so was published online November 12th in Developmental Science. This research was done by psychologist Martin Doherty of Stirling University in Scotland and his colleagues.

realtive sizes optical illusion - bYou may see three different versions of Ebbinghaus Optical Illusion test accompanying this article. Visual context can be experimentally manipulated to distort adults’ perception of objects’ sizes. But strangely, Doherty’s group finds that children, especially those younger than 7, show little evidence of altered size perception on a tasks such as Ebbinghaus illusion. Other investigators have noted that children with autism don’t succumb to visual size illusions, consistent with the idea that autism involves an excessive focus on details. (more…)

But visual context largely eludes all young children, not just those with autism. Doherty’s team studied 151 children, ages 4 to 10, recruited from a Scottish primary and nursery school. Another 24 volunteers, ages 18 to 25, were college students. You may see the test we are talking about presented in the example below:


Participants viewed a series of images containing pairs of orange circles in which one circle was 2 percent to 18 percent larger than the other. An experimenter asked participants to point to the circle that looked bigger. Control images showed only two orange circles. In other images, each orange circle was surrounded by gray circles intended either to hinder or aid accurate size perception.

realtive sizes optical illusion - c

Misleading images showed the smaller orange circle surrounded by even smaller gray circles to boost its apparent size. Large gray circles surrounding the larger orange circle were intended to shrink its apparent size. In helpful images, large gray circles surrounded the smaller orange circle to make it appear smaller than it actually was. Small circles surrounded the larger orange circle to magnify its apparent size.

4-year-olds correctly identified the larger circle in 79 percent of control images. That figure rose with age, reaching 95 percent in adults. For 4- to 6-year-olds, accuracy of size perception for misleading images remained at about what it was for control images. Misleading images increasingly elicited errors from older children and tricked adults most of the time. Adults made almost no errors on helpful images. Kids from age 7 to 10 erred on a minority of helpful images, while 4- to 6-year-olds performed no better than chance.

47 Replies to “Illusions Fool Adults, But Not Kids”

  1. Why is there a (more…) in the middle of the post?

    Well, if this is what you call “long”, just keep posting lng stories then.

  2. yah it was a long artical, but a cool illusion. it must really work because I am a kid and I knew exactlly what it was as soon as i saw it

  3. My 9 year old obviously looks at your website too much because her perceptions were the same as mine (incorrect answer on the orange dot with the misleading context)I had to use a ruler to prove to her that the left hand circle was actually bigger. But my 4 year old gave the correct answer! Very interesting research. Maybe you should have a minimum age recommendation on your website as little kids just won’t get it.

  4. as a psycology student and as a normal person (if i can be classed as normal =D) i found this post very intresting and the lengh of it was not a bad thing thanks for all the illusions so far and please keep up the excellent work :)

  5. Vurdlak, I think it’s shocking that you keep presenting this “adult” material on your website. What if an innocent child was to see these images? Shame on you!

  6. What is so so adult about the images? can someone please tell me? if they are, then please give me a title for porns.

  7. Wonderful!! I saw the iGoogle-widget and thought “/care.” But then I read the title “Illusions Fool Adults, But Not Kids” and you got my attention.

    I’m sorry for doubting you! I will start to read the page every time, from now on, no matter what!

  8. Cool research… But. Just tried it on my 4-year-old son… He pointed to the dot in the “small” context as being bigger, just as an adult would think…
    No question in his mind, the dot in the small cube/surrounded by the smaller dots is definitely bigger!
    I wonder if that says something about the research, or about my 4-year-old’s brain… :D

  9. Tried it another time… (Read the instructions better this time… :-) )
    Now he identified the orange dots correct!
    Last time he doubted, this time he was sure, especially in the Misleading Context.
    Pfew, almost had me worried there! ;-)

  10. I am 44 and I am not fooled by the illusion. I am an dyslectic person. Maybe this is why? Somethimes I don’t even get the idea. I just cann’t see the illusion. I have to read the whole instruction to get it.

  11. This was fantastic! This is the sort of information that turned me on to this site! Stay away from the advertising…. and keep giving us more about the science and psychology of the reasons why we perceive the world the way we do!
    Very interesting!
    Our perception is not only the oldest form of psychology but to some philosophists the only thing that actually exists! I understand that will be a bit deep for some… but it makes you think hey?…..
    Nice job!
    Give us more of this!

  12. I’m of reasonable age (teen) and I could locate which one was bigger on each picture without a ruler. Really it wasn’t that hard.

  13. Nice article! I’ve been looking at your site for about a year now and wonder if you have described the most fundamental illusion of them all. People see the lines drawn on the paper as a cube! It is not. Once the context has been “fantasized” the rest follows logically; of course one dot is bigger than the rest; it is a direct result of the original illusion. By the way this works in politics as well.

    Thanks for the good work. Michael

  14. I’m a teenager and I understood half of those illusions. Even after pondering the no context one I still got it wrong. :( Maybe I’m getting old.

  15. One of the most difficult problems in AI is providing machines with sight. It was originally thought to be an easy problem. Hook up a camera to a computer, let it interpret the image and away we go. The problem is what you really have (and its also true for the human eye) is a mass of pixels that need organizing so that what is seen can be accounted for. I have to mentally organize what I see right now so that I know what I’m looking at is a monitor, then I can look at the details on the monitor (which then asks that the brain provide even more context). Organizing the feedback from light is the heavy lifting of sight.

    I’m not trying to give a lecture. What I’m curious about is would computers also be vulnerable to optical illusion if sight was routine for them.

  16. omg! i just figured sonething out! when looking at the last picture (the one with lots of dots) scroll up and down the dots appear to be getting smaller and larger!
    but, maybe im just a freak…

  17. Rev Mattumagala Chandananda
    Sri Vinayalankaramaya,

    Dear Mr Vurdlak ,

    I am a thirty eight years old Buddhist monk (priest) from Srilanka. I started to learn psychology just one year ago. I am inspired by your optical and perceptual illusions. For me most illusions reveal a spiritually valuable truth. For an example how many crimes occur in the world due to wrong perception or due to believing too much in our eyes, years ……. and mind? How much human conflicts and suffering arise due to distorted views
    I use some of your illusions to teach people how much erroneous our way of thinking can be. Then we can encourage them to improve mindfulness and vigilance, to practice patience and to achieve quality of forgiving others. I struggle to promote humanity in the society , by preaching, counseling, writing etc. Unfortunately many people in our country do not know English and internet facilities also very poor, because it is a third world country. I am going to write a small booklet, which is for free distribution, for the above mentioned purpose.
    So dear sir , could you please grant me the permission, to use few of your illusions for my book? I promise you to include citation
    May you have more creative intelligence and peace of mind to serve the world. May the god bless you.

    Thank you
    Yours sincerely,
    Rev. Mattumagala Chandananda

  18. This optical illusion is REALLY amazin!

    BTW,My fave catagory that u do are “Spot The Object” even though i cant do many of them, i find it good all the same =]

  19. I’m 13 and the illusion, I think is that the dots appear to be different sizes but really aren’t. Am I under thinking this or over thinking it?

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