Optical Illusions, and Ocular Dominance

We were playing around with some optical illusions in Roy Richards' 101 Science Tricks, in preparation for our stART (story + ART) project, for tomorrow (you'll have to wait to see that one).

The illusions in Richards' book are the type where you place a piece of cardboard between two, side by side images, then look at them, with your nose pressed against the cardboard, so they merge together, into one image.

As we were playing with them, moving the fish into the fish bowl, and spider onto its web, we started wondering what would happen if you merged two dots of color.

After some trial, and error...



...we managed to draw two dots, on either side of a line, so when looked at with a piece of cardboard between them...



...they came together. Of course, they don't come together in the photograph, because it's only an optical illusion, that makes them seem to come together, but hopefully, you get the idea.



What was interesting was, that the dots didn't merge together. Instead, one dot covered the other. I drew several, with different color combinations, and we looked at them.

For me, the dot on the right, always covered the dot on the left, and I realized we'd just moved out of experimenting with optical illusions, and into testing ocular dominance.

The children, and the Man of the House, each took turns looking at the dots, and we recorded which dot covered which, for each of them. My husband, the boys, and I, all seem to be right eyed. E (age 5) couldn't make the dots come together at all, but C (age 4) claimed to see the left hand dot on top, each time. The two older girls went back and forth, between right, and left.

We are all right handed, except for my middle daughter, but it turns out being right, or left eyed, has little to do with whether you are right, or left handed. You can read all about it, here, in the Wikipedia entry on ocular dominance.

Even so, I was uncertain about the results, especially for my four year old. So, I searched around, and found another test for eye sightedness, at Neuroscience for Kids.

Following the instructions there, I handed the children a toilet paper tube, and ask them to look through it, at a spot on the wall. The eye they choose to look through, is supposed to be their dominant side, and it did seem to agree with the results from our color dot test.

At least, it did, for everyone, but me. I was right eyed with the color dots, but I put the tube, very naturally, to my left eye. That actually goes a long way to explaining some of the trouble I had the last time we went target shooting, but that's another story.

It's great to be a homeschooler.