Developmental leaps in a baby - Leap 1-10

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Hanna Pauser
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Have you noticed that your baby sometimes becomes extra fussy or clingy, only to suddenly surprise you with a new skill? This is often referred to as a developmental leap. Here, we’ll cover everything you need to know.

What is a Developmental Leap?

A developmental leap refers to a period when a baby undergoes a phase of intense mental or motor development. During these periods, it is common for the baby’s behavior to change. Your baby might become fussier, cry more often, and seek more closeness. Afterward, you may sometimes notice that the baby has gained new skills or insights.

There are theories suggesting that developmental leaps occur at specific times in a baby’s life. However, this is not a recognized theory within healthcare.

Developmental leaps and The Wonder Weeks

In the book The Wonder Weeks (1992), three Dutch researchers presented a theory that babies go through ten distinct developmental leaps at fixed times during the first 20 months of life.

Critics argue that The Wonder Weeks is based on studies that are too small to be replicated and that the theory does not account for individual developmental rates or the brain's adaptability.

Despite lacking scientific support and not being used in healthcare, the theory is popular among many parents who feel that the descriptions and timing align with their experiences.

Developmental leaps vs. milestones

In healthcare, milestones are instead used as tools to assess whether a child is developing normally. Milestones are skills that most children demonstrate by a certain age.

Healthcare professionals emphasize, however, that every child develops at their own pace and that it is important to consider the overall picture when assessing normal development.

Developmental leaps according to The Wonder Weeks Leap 1: “Sensations” (4–5 weeks from due date)

According to the authors of The Wonder Weeks, the first leap occurs around five weeks old. After this leap, you may notice that your baby is more interested in their surroundings and responds more during interactions with you. They also see slightly better at distances of about 20–25 cm.

The authors suggest that while babies are more interested in new sensations, they are also more sensitive and easily overstimulated.

New abilities after the leap:

  • Can focus on objects for longer periods.

  • Pays more attention to sounds and can turn their head toward the source.

  • Follows movements and faces with greater interest.

Leap 2: “Patterns” (7–9 weeks or around 2 months from due date)

During this leap, babies develop the ability to notice simple patterns in their environment and their bodies. This changes how they see, smell, taste, and feel.

The leap is also marked by less reflexive and more deliberate movements, even though control is still limited.

New abilities after the leap:

  • Can focus their gaze better.

  • Has discovered their hands and feet.

  • Explores making short, sudden sounds like “ah,” “uh,” and “ehh.”

  • Makes movements that seem more deliberate, though still jerky.

  • Shows greater interest in objects and people.

Leap 3: “Smooth Transitions” (11–12 weeks or around 3 months from due date)

The third leap, occurring around 11–12 weeks, involves developing smoother transitions in both motor skills and perception of the environment. Babies begin to move more fluidly and gain a more nuanced understanding of their surroundings.

New abilities after the leap:

  • Smoother and more controlled movements.

  • Increased understanding and awareness of their environment.

  • Better ability to track moving objects with their gaze.

  • Greater need for stimuli and variation.

Leap 4: “Events” (18–20 weeks or around 4 months and 3 weeks from due date)

During this leap, babies begin to understand sequences of events and perform movements in a more continuous flow, improving their coordination.

New abilities after the leap:

  • Better coordination of movements.

  • Improved ability to reach for and grab objects.

  • Starts exploring movements like rolling over or attempting to crawl.

  • “Babbles” in longer strings of sounds.

  • Understands that actions lead to results.

Leap 5: “Relationships” (26 weeks / 6 months from due date)

At this stage, babies start understanding relationships between people and objects. They begin to grasp distance, which may lead to separation anxiety but also motivates them to crawl or move toward things.

New abilities after the leap:

  • Interest in stacking or grouping objects.

  • Looks for hidden objects and understands where they might be.

  • Stronger reactions to people coming and going.

  • Noticing deviations in routine, such as something falling.

Leap 6: “Categories” (37 weeks / 8 months and 1 week from due date)

During this leap, babies start to group objects into categories. They understand similarities and differences between items and may begin recognizing these relationships.

New abilities after the leap:

  • Investigates objects thoroughly and with focus.

  • Recognizes items in photos or images.

  • Shows preferences for certain toys or objects.

  • Understands that items with similar functions (e.g., spoons) belong to the same category.

Leap 7: “Sequences” (46 weeks / 10 months and 2 weeks from due date)

This leap involves understanding sequences—knowing that certain actions must follow in a specific order.

New abilities after the leap:

  • Awareness of the order of tasks, such as putting socks on before shoes.

  • Following step-by-step actions, like moving a toy car along a track.

  • Interest in simple puzzles or building toys.

  • Increased frustration if expected sequences are disrupted.

Leap 8: “Programs” (55 weeks / 1 year and 3 weeks from due date)

Babies begin to plan and execute a series of actions, understanding how to complete tasks like setting a table or simulating everyday activities.

New abilities after the leap:

  • Exploring options within a task and their outcomes.

  • Planning steps, such as gathering items for setting the table.

  • Beginning to resist tasks like dressing if they predict what’s coming.

  • Playing games that mimic real-life situations.

Leap 9: “Principles” (64 weeks / 1 year and 3 months from due date)

At this stage, babies start to understand that certain actions are governed by rules or principles, enabling them to act more freely within these guidelines.

New abilities after the leap:

  • Stronger expression of personal will.

  • Engages in imaginative play with more detail and finesse.

  • Tries out different ways to achieve a goal.

  • Becomes more protective of toys or possessions.

Leap 10: “Systems” (75 weeks / 1 year and 5 months from due date)

The final leap involves recognizing systems and how they interconnect. Babies now adapt principles learned earlier to make decisions and act more flexibly.

New abilities after the leap:

  • A stronger sense of self, using words like “I” and “you.”

  • Keen interest in doing things independently.

  • Chooses whether or not to apply moral principles.

  • Fascination with animals and insects.

  • Can explore how to manipulate their environment with a clearer understanding of cause and effect.

1. Plooij FX, van de Rijt H, Plooij X. The Wonder Weeks: How to Stimulate Your Baby's Mental Development and Help Them Turn Their 10 Predictable, Great, Fussy Phases into Magical Leaps Forward. Kiddy World Publishing; 2017.