Well, your kid now must have begun to see himself as a self-sufficient individual, capable of resolving his own issues. So you as a parent now need to understand that the cognitive phase has started. If your kid has started to do something in an expected manner, there’s nothing to be surprised about as your kid is becoming just more organized.
What you need to know
In fact this is a period when your kid will learn to grasp things mentally in a well designated manner. So as a parent why not lend a helping hand to them and nurture them to come out with the best? You can make your kid even more capable by challenging his reasoning or thought processes. For example, opt for memory games and sit back to see what the outcome is.
Since this is the time when they will learn reasoning abilities as well, try to question your kid as frequently as you can, as this will make a smarter and more capable person out of your kid. So help your kid develop fully during this cognitive period.