Brayden was a highly overstimulated baby due in large part to my excellent entertaining skills. Once I started to back off, he chilled out. I had, however, trained him to need entertainment. When it came time for independent playtime, he had a rough go getting started. We had to start with 5 minutes and work our way up over time. He did get there, but it took time.
When Kaitlyn came along, I was not the entertainer to her that I was to Brayden. Part of the reason is that with a 22 month old child, I didn't have the time available to me to entertain her like I had Brayden. But the main reason for it is that I had learned my lesson with Brayden.
Babies don't need the stimulation we need in order to be entertained. Everything is new and interesting. It takes very little to teach and interest them. With Kaitlyn, I learned to just let her sit there. She could be in the room with me and be fully fascinated by the normal happenings of the household. I didn't need to be constantly singing, touching, bouncing, performing, showing toys, etc. She was not an over-stimulated baby. She was content and happy. And in case you read that and worry that if you do the same your child will be less intelligent...Kaitlyn (now 14 months) is proving to be ridiculously smart.
When we started independent playtime with Kaitlyn, it was easy. I put her in the playpen, expecting to have her cry or fuss for a full 5 minutes before I got her. Well, she happily played for 15 minutes before I decided that was long enough for her age and got her out. We have never had a problem with her and independent playtime.
So no matter the age of your baby, try to provide proper stimulation for his needs. Over-stimulation is not going to do anyone any favors. If you find your baby has become overstimulated, take note of what waketime was like and adjust waketime activities in the future. Just because your child is awake doesn't mean you need to be in front of his face putting on a show. Let him have some time to observe. Let him have time to himself. Realize that even a diaper change for a newborn is quite the stimulating activity.