Babies go through 8 neurological growth spurts in the first 14 months, and research detailed in "The Wonder Weeks" by Vanderijt and Plooij can even tell you within a few weeks, when these spurts will happen, the new skills baby is learning, and how it may affect them. It also tells you how to help baby to develop the new skills. The spurts in the first year occur at around 5,8,12, 15, 23, 34, 42 and 51 weeks.
Before any of these growth spurts a sudden change in the nervous system occurs bringing a completely new type of perception about the world, and baby has to develop a completely new set of skills to deal with the new perception. During these times babies are understandably confused and need extra attention, and reassurance. Babies cry more, feed more and need you more during a spurt, but rather than see these as difficult fussy times, you can see these as exciting times of growth. There are new skills that you can help her to explore and develop. After all, how would you feel if you suddenly found the world had extra dimensions you never knew about, or you could see things you never saw before, or realised that you were actually completely dependent and defenseless?
I bought The Wonder Weeks when my son was about 4 months old and it was my "go-to" book for a long time when he started to act a bit fussy. It allowed me to understand his development and to relax when he was fussy and understand that I could help him through it without panicking about whether he might be unwell.
At 4-5 weeks baby changes the way he experiences the world, how he feels and how he digests food. Everything sees, feels, hears, smells and tastes different. If you understand this you can pay more attention to what he is perceiving and starting to like and dislike. It's fascinating and can build an even stronger bond between you.
At around 7-8 weeks her brain waves pattern change and she starts to recognise shapes and patterns. She starts to understand that her arms and hands belong to her. She develops more control of her body, eyes and vocal cords. She might start to explore this by hold her body in different positions and moving her arms around more purposefully just to see how it feels. She might watch your mouth when you talk, or start making noises to start a conversation with you.
At around 12 weeks a developmental change occurs that changes the jerky body movements to much smoother transition movements. At the same time he starts to perceive smooth movements, like the light becoming dimmer in the evening, or a voice changing register or a cat slowly stalking across a room. Suddenly everything seems to be moving. The world which was much more static yesterday is changing all around him.
At around 19 weeks she begins to understand how transitions fit together. She starts to reach out for a toy, pick it up, turn it round to inspect it and put it in her mouth - all deliberately. She now understands how this all fits together. She will try to roll over, and to move and try to put sounds together. Understanding how actions fit together is complex, and can take a few weeks for baby to get used to. She starts to learn how to correct movements, e.g. moving a toy slightly to the left so she can see it better etc.
Around week 26 baby starts to understand relationships. Suddenly he starts to realise distance between objects, or between people. This is quite terrifying. Until now he had no understanding that he is very small in a very large world, and has no way to get to something outside his cot, or on a shelf, or to get to mum if she isn't beside him. Suddenly he realises that mum can leave and there is nothing he can do about it. Understandably this is very disconcerting and baby can become extremely clingy. As he starts to lean about distances and relationships he begins to understand the concepts of inside, outside, on top, above, next to, underneath and in between. Isn't it amazing?
Another change in brainwaves happens around 37 weeks, which sees baby starting to understand about categories, e.g. big dogs and small dogs are all dogs, rice and apples are both food. Horses in the field, and horses in a book, and toy horses are all horses, even though one is alive, one is a picture and one is made of clay or plastic. Understanding categories affects every sense. It allows her to start to learn about emotions. Her thinking now starts to become more like an adults, and as such we can start to understand each other better.
The next spurt is around 46 weeks when baby truely starts to put things all together. He now looks at how things go together before attempting them. He may start to look at his shape sorter and try to work out the correct shape for the hole, instead of randomly trying slots. For the first time he may try constructing things and linking things, like aiming a ball before throwing, or building a tower with blocks. He may start to brush his hair or try to undress or dress himself, or point to things so that you can name them for him to build his vocabulary.
Just after his first birthday (around 55 weeks) another big change in understanding occurs. It allows baby to build on the idea of sequences of behaviours and understand how they fit together to meet a goal. She can now start to understand what it means to go shopping, or do the laundry or phone someone. You might go to different shops or phone different people, or use the phone in different rooms, but it meets the same goal. This can start the process of imaginative play with her toys. She can now start to consciously develop her own programs and make decisions, like deciding to have one bite of lunch and then a drink, or start with the drink before eating. She can decide whether to use the spoon or feel the food on her hands. Bet you never really thought about lunch as a decision making exercise before :)
It's an amazing journey from a newborn to a decision making toddler, but the leaps are hard for baby and caregiver. When baby first starts to perceive these new things it's like his world has turned upside down. The things he understood yesterday, no longer fit the world any more - they don't explain what he is sensing. This can start a couple of weeks before the actual spurt. Once the neurological change has occurred, it can then take another couple of weeks for baby to make sense of the change and create a new mental picture of the world. This means that your baby could be unsettled for a few weeks around each growth spurt. Then length of time depends on the temperament of the baby and how easily he adjusts to the change.
During these few weeks baby can have trouble sleeping, be shy, need to be kept busy and demand attention. He can lose his appetite, become less vocal, and clingy to mum. If breastfeeding he may want to comfort feed a lot as that can meet a lot of the needs to help him sleep and keep him close to mum and allow him to have her attention.
This is understandably hard on mum (or other caregiver). Mums complain of being exhausted, feeling trapped, and annoyed, whilst at the same time being concerned that baby is ill, or not herself. It's hard when you are going through these times, but at least if you understand why your baby is feeling lost, it is a little easier to deal with. It is easier to just hold them and show them that you will not leave. It is easier to deal with the night waking, and the clinging behaviour.
So remember folks, when your baby seems to start a sleep regression, or act fussy - maybe they are actually growing. Maybe it is a wonderful sign. Hold them closer. This is not a sign of a sleep problem, or need for training. Have some empathy for what is going on, and shape your play around the growth. If baby is learning about categories, tell them about different things that fit in the same category. If baby is learning about fitting things together, build lots of towers. If baby wants to be fed again, for the 3rd time in an hour, just try to relax. Your baby is growing. He is developing, and growth can be scarey, but you can help. You can create a safe space where he can figure out his world, and know that in a couple more weeks you will understand each other more fully.
"People are not born once and for all on the day
that their mother puts them on to the Earth,
but...time and again,
life forces them to enter a new world on their own"
Love in the time of Cholera, Gabriel Garcia Marquez
(quoted from The Wonder Weeks)
The Wonder Weeks, by Hetty Vanderijt, PhD and Frans Plooij, PhD