1. Overview

With leap three, at around 12 weeks (3 months), your baby will enter yet another new world as they undergo the third major neurodevelopmental leap since their birth. You may recall that one of the significant physical developments that occurred around eight-weeks-old (leap two) was your baby’s ability to swipe and kick at objects with their arms and legs. These early flailing movements often would have looked comically puppet-like during that time. However, at 12 weeks this jerky action is about to change. Like Pinocchio, your baby is ready to change from a puppet in to a real child.

Of course, this transformation will not happen overnight and when it does it will entail more than just physical movement, although that is probably what you will notice most. It will also affect your baby’s ability to perceive with their other senses the way things change around them… such as a voice shifting from one register to another, the cat slinking across the floor, and the light in a room becoming dimmer as the sun dips behind the clouds. The world of your baby is becoming a more organized place as they discover the constant, flowing, changes around them.

During the first year your baby will learn things that you find so natural and simple that you no longer notice them. But for your baby, they are the most complex things they can handle and are, therefore, their peak experiences. The perception and control of patterns (leap two) is followed by the ability to perceive smooth transitions (leap three) that enable your baby to move around, appearing less stiff and robotic. That new ability is also reflected in the way that your baby plays with their voice and is the reason that they may love to play ‘airplane.’

This leap in to the perceptual World of Smooth Transitions is age-linked and predictable. It follows a dramatic increase in your baby’s head circumference, around 10 to 11 weeks of age, which indicates that your baby’s brain size has suddenly increased. This leap sets the development of a whole range of skills and activities in motion. However, the age that these appear for the first time varies greatly and depends on your baby’s preferences, experimentation, and physical development. For example, the ability to perceive smooth transitions is a necessary precondition for your baby to attempt to stand up while helped by you, or other caregivers, but this ability can appear anywhere from three to eight months.