0-1 month: like to look at shapes, curves and contrasting colors.
1-2 months: like bright colors, and strong black and white contrast.
2-3 months: distinguish yellow, red and orange.
3-8 months: can distinguish two different shades of the same color.
8-12 months: distinguish simple geometric shapes.
1-3 years: began to have more understanding of the near Baby & Toddler Toy and far, front and back, left and right and other three-dimensional space.
3-4 years: can distinguish red, yellow, blue, green, orange, purple and other basic colors.
5-6 years: gradually recognize all the colors, but stereoscopic function is incomplete.
9 years+: be same as adults basically.