A team led by psychologist Martin Doherty of the University of Stirling in Scotland found that visual illusions that befuddle adults don't effect children as easily. The pair of orange circles in the above illusion are slightly different in size. The blue dots will either accentuate those differences, or mislead the eye into thinking they are bigger or smaller than they are. In an experiment, participants of different ages were asked to identify the circle that looked bigger.
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.
The results suggest that considering context in images is something we learn as we age. Link