Your Child's Crib is Just for Sleeping
Do you put your baby in their crib to play a few times a day? I do not advise putting your child into their crib to play. There are plenty of alternative safe spaces for your baby for playtime and fun.
The crib should be reserved for sleep and only for sleep. Just like a toilet is reserved for going to the bathroom. The goal here is a clear message.
Many sleep books will tell you to do playtime in the crib in order to create a positive association of the crib for your child. In actuality, it does the opposite. Using the crib as a space to play creates a confusing message, and a confusing message is unfair to your child.
Only put your child in their crib to sleep as you are asking them to do one consistent thing in there; sleep.
If you sometimes put your child in their crib to sleep and sometimes put them in their crib to play, you are sending a big mixed message.
You must erase how you see things and get into your baby's brain to see how they may see the world. What makes sense to you often makes no sense to your baby. Why? Babies and kids see things from a behavioral perspective.
Your baby cannot differentiate between sleep time and playtime if they are in the exact same environment. In your case, that environment is the crib. "Hmmm, sometimes my mom puts me in my crib and wants me to sleep. And sometimes, she puts me in my crib to read and play. I don't get it. What on Earth does she want me to do?"
The keyword is "Sometimes". Your baby knows that even if you are putting her to sleep, playing is also a possibility as sometimes she does that! Therefore, she will use her free will and strong will to fight sleep until the bitter end, to get that idea met.
Why? Because she knows it is possible, and she does not know or understand your logic. This is what is called "Intermittent reinforcement". It is a powerful force that drives human behavior and creates great confusion for babies and adults.
Your child does not look and check her mini Apple watch when you put her in her crib with all her toys and think, "Oh yeah, I get it. This makes sense; it is 11:00 AM, so it's playtime. Sleep time is later at 7:00 PM".
Your baby thinks: "My mom is so crazy! Sometimes she wants me to do X in here, and other times she wants me to Z. I have no idea what I am supposed to do."
Children deserve to know what is expected of them. It is through the consistency of your words and actions that they can then understand and learn, and here is the biggie: trust you! Consistency fosters TRUST. The crib must be a pure sleep space—a child-safe mattress with a tightly fitted sheet.
No toys, no books, and just a lovely* (if over age one). Her sleeping environment should stay the same from bedtime to waketime. Her bedtime routine should be the same every night. However, read different books! The same book over and over every night is a total snoozer.
Focus on the sequencing and the bedtime vibe. Your child can then say to herself: "Oh yeah, I get this, and I got this. Here I am, and here is my lovey Fred. I know what to do! It is time to sleep!" Remember, you will never "convince" your child to sleep. Nor should you try. Sleep is a skill for you to teach your child and deserves to be a consistent house rule.
*If your child uses a lovey, please keep it in the crib and only in the crib. Wash it frequently. Taking it to school or on the subway is a recipe for sickness. We want a fuzzy BFF, not a fuzzy petri dish.