My son did a human behavior project in 8th grade on optical illusions. He gathered a sample of maybe a dozen different ones, and included something like this, only with flash cards, as a bonus. (He's 27 now, so that was the only kind of "flash" available at the time.) It was the only one that had right or wrong answers. For the other ones, he recorded what the person saw.

He kept a record of their responses and graphed them according to gender, age, and left- or right-handedness, to see if it made any difference. His thought was, perhaps perception is affected by hand, and by extension, eye, dominance. Left hand / right eye, and vice versa. According to his sample of about 50 people, including an inordinant number of lefties (our family has a lot of 'em), it isn't.

He did find that young children, regardless of gender, had a lot less trouble with the color/word question. It wasn't because they had more agile minds. It was because they mostly didn't read yet, or were new readers. Their minds weren't cluttered up with all that knowledge.