Cognitive development refers to your child's ability to learn, think and problem solve. While every child develops at a different rate typically by the age of four your child will be able to recall parts of a story when you read to them. So if you're reading them a story they may be able to tell you what happens in the end which is a lot of fun if you give them the opportunity to do so.
Another thing that they're able to do is they're now able to draw a body with two to four body parts. So usually a smiley face with the eyes, the nose and the mouth. So it's really great to get them drawing and learning through experience. They're also able to complete more challenging puzzles like four to five piece puzzles. Also typically by the age of four your child is able to understand the concept of counting and they will know some numbers.
They're also very into playing board games. In addition, their fine motor skills are also becoming stronger. So this is a great time to introduce games using things such as tweezers or having them use more of their fine motor skills. So games like don't spill the beans where they're picking up the beans and they're trying to balance it on a game or even if you just made a rice bin. You got out a bin and you put rice in it. You threw some beans in it and you had your child digging in the rice and trying to find beans. That's a really fun game that they'll enjoy doing.
Another great thing that your child is able to do at this age is they understand the difference between same and different. So engaging your child in talking to them about, what color hair do you have? Brown hair. What about your friend's hair? What about mommy's hair? And your child will be able to say, mommy has the same hair as me. And it's really a lot of fun to see them know these things and to be able to tell you them.
And a great thing to do would be to take out paper and since they're drawing their little smiley faces and pictures get out some little yarn. Get out you know, yellow yarn for blonde hair and brown yarn for brown hair and try to tell them to say, okay, here's you and here's mommy. Are we the same or are we different? Hair? And you know you could explore more with eyes and so on, but this is really a great time to watch them learn and grow.