The Wonder Weeks: A Forecast For Your Baby’s Development
By Dr. Katie Gleisner
A child experiences an incredible period of mental and physical growth through the first three years of life. Their nervous system is required to jump over developmental hurdles that play a crucial role on how your baby experiences, interacts, and grows. Babies were designed to learn. It may seem that some evenings you put to bed a completely different baby then the one who wakes up the following morning. What could have possibly happened over the span of a few hours? So much, as a baby is born with 100 billion neurons that are constantly firing and wiring new pathways to recognize faces, coordinate movement, smile, and learn languages.
The brain is designed to be sensitive to new experiences. All babies go through ten mental development leaps throughout their first twenty months of life, The Wonder Weeks. They all go through each of the leaps at the same time. With each new leap, your baby is able to learn new things. However, all of this dramatic development can cause fussy and difficult days for your little one. The Wonder Weeks are based on neurological research and shared parental experiences. We tend to track our babies’ physical milestones—holding their head up, rolling over, sitting, crawling, and walking—more so than their mental leaps. Monitoring your baby’s Wonder Weeks will help you forecast their grumpy days or weeks, and get a glimpse into their new experiences with every leap.
Throughout the first month of life you are getting to know your new family member and in awe of how rapidly they grow. Around five weeks your baby enters their first leap. This leap impacts your baby’s senses. They will experience heightened sensations inside and out. Internally, your baby’s digestive tract is undergoing remodeling and their metabolism fluctuates. Externally, your baby’s visual, auditory, and tactile senses are heightened. As your baby embarks on a rapidly changing world, they may express the three C’s: crying, clinginess, and crankiness. Throughout this fussy phase, your baby will crave more comfort, so the day will be filled with more cuddles, walks, and gentle massages. Your voice, scent, and touch will be soothing and create a sense of ease for your baby as they experience the vibrancy of their new world. At the end of leap one, your baby will be more alert and preoccupied with looking and listening, as well as smiling and gurgling with pleasure.
Now that your little one is able to experience their world in a new way they will jump into leap two. At eight weeks old, your baby’s head circumference dramatically increases and their brain waves change, which allows them to start recognizing recurring shapes, patterns, and structures. If you start to notice your baby having fussier moments, it is likely they are preparing to learn new skills. They will find their hands and feet and explore how they taste and move to grasp an elusive toy. They will be fascinated by the contrast and movement of shadows against the bright wall, as well as colorful books and knick knacks on a shelf. Your baby will gain more control of their body, too. They will explore holding their head up, kicking, and rolling, as well as making silly faces and sounds as they discover their facial muscles and vocal cords, respectively.
At twelve weeks your baby will enter their third leap. This developmental milestone allows your baby to smoothly coordinate their body and perception of their world. You may start to notice that your baby’s sporadic movements become smoother and coordinated. They are able to control their hands, feet, head, eyes, and vocal cords. When they reach for a toy or pull to sit while holding your fingers it will be with a deliberate, controlled motion. They are intrigued by the change of daylight, the pitch of the dog barking, and the movement of family members. With each day your baby’s world is becoming more organized as they are constantly learning new skills.
At four months, babies’ brain waves dramatically change, and their head circumference increases. This primes your baby for their fourth leap at nineteen weeks. Through this leap your baby begins to understand events, or short familiar patterns. For example, a few weeks ago your wee one needed full concentration to grasp an object in front of them, but now they begin to understand that they can grab it, shake it, and put it in their mouth. This movement requires intense focus and coordination. The fourth leap is trying, resulting in more fussy weeks as they grow comfortable with the changes to how they see, hear, smell, taste, and feel their world.
A few weeks of calm pass by as your baby wiggles away to explore before they enter their fifth leap. At twenty-six weeks your baby will begin to understand relationships. The biggest lesson is learning the distance between their parents and themselves. Your baby will cry and fuss to be in your arms, but once they have reached their goal, they will squirm away to discover more interesting things in the world around them. Typically, fussiness during this age is associated with teething. However, it is also related to your baby’s ability to understand and develop new skills with people, objects, sounds, and feelings.
Between the fifth and sixth leaps you may notice your baby’s personality and interests developing. Every baby is different, but they all love anything new. Showing excitement in your baby’s new skills or interest will spark and accelerate their learning process. At thirty-seven weeks your baby will enter their sixth leap, which is focused around investigation and categorization in their world. They are able to recognize people, objects, and animals. Now, they are able to differentiate between items as they categorize them throughout their senses. In addition, their understanding of language will soar, even if they are not talking yet. Through this leap you may notice your baby being grumpy, restless, and impatient as they go through another big change. After the leap, they will be able to divide their world into categories. They will be able to differentiate between a dog, cat, or bird, but also the characteristics that make something small, big, light, heavy, soft, or sticky, as well as emotions.
With each leap your baby’s world continues to expand. In between the sixth and seventh leap you may find that your baby has a knack for destruction. A part of understanding an object is by taking it apart and fiddling. However, around forty-six weeks your baby will enter their seventh leap, which allows them to put things together. After a few weeks of fussy, sleepless nights, your little one will be able to point out and name an item, respond “meow” to your question, “what does a cat say?,” put objects in and out of a container, and push an object to where they want to go and discover next.
A few weeks after their first birthday, around fifty-five weeks, your baby will enter the eight leap. They will begin to understand programs throughout their day including getting dressed, eating lunch, and going to bed. Your baby will be eager to “help” and may insist on doing things themselves. This leap provides them flexibility and independence to discover their world. They may be prone to temper tantrums when their “plan” does not coincide with yours. However, at the end of eighth leap your toddler will initiate activities, be eager to “help,” and study how you and others carry out everyday programs.
Your cheerful and independent toddler will enter their ninth leap at six four weeks. Typically, they will experience a few weeks of clinginess and cuddles before they burst into activity. During the ninth leap they are preoccupied with thinking and strategizing about what they want and what they are doing. As they become more physically and verbally skillful everyday is a new adventure.
With each leap your little one is becoming more independent and developing their personality. Between the ninth and tenth leap you may notice more bouts of moody, obstinate “teenager” behavior. This independent streak continues as they jump into the tenth leap around seventy-five weeks. Your toddler discovers that they control their body and can make choices for themselves. Some toddlers are fascinated by their body and what it can do. Or they are preoccupied with their families, friends, and house. Others may be enchanted by drawing, music, or physics. Every toddler has different mobility, preferences, and talents that allow them to develop into unique individuals.
Throughout infancy and childhood, your child will continue to learn and observe as they develop their outlook on life. Your love, patience, and all those sleepless nights are worth it as you watch this tiny being discover whether they like to talk, build, music, or physical play. The Wonder Weeks provides you insight into their development and variable moods along the way. Use their moods and behaviors as a barometer. If you notice that your baby is clingy, craving cuddles, or fighting sleep watch them closely as there is a good chance they are learning a new skill and need extra support. Following along with The Wonder Weeks Book or app creates an interactive way to track your baby’s development, and give yourself some grace through these hurdles.