From the moment of birth, babies are taking in sensory information from the world around them — and while the senses are immature at birth, they are already functional and actively shaping the development of the brain. The richness of sensory experience in early childhood is not incidental to development; it is one of the primary drivers of the neural connection formation that underlies learning, thinking, and behaviour throughout life.
Understanding how each sense develops in the first three years, what the normal range of development looks like, and what parents can observe for helps families support sensory development and identify any concerns early.
Healthbooq supports parents in tracking their child's sensory and developmental milestones with age-appropriate guidance from birth through the early years.
Vision
At birth, vision is the least mature of the senses. Newborns are effectively short-sighted — they see most clearly at about twenty to thirty centimetres, which is approximately the distance between a feeding baby and their parent's face. Faces are disproportionately interesting to newborns, and the high contrast of hairline against face, eyes, and mouth are the features most visually engaging. Colour vision is limited in the first months; the high contrast between black and white is more engaging than pastel colours.
Visual acuity improves rapidly over the first year. By four months most babies can track a moving object across their full visual field and begin to reach accurately for objects they see. By six months, binocular vision — the ability to use both eyes together to perceive depth — is established. By twelve months, visual acuity is approximately 20/50 (adult normal is 20/20) and continues to improve through early childhood.
Squint (strabismus) — where one eye turns in or out — should be assessed by a GP if noticed at any point, but is particularly important to address before three to four years, before which amblyopia (lazy eye) is most effectively treated with patching.
Hearing
Hearing is more developed at birth than vision. The newborn has been hearing sounds in the womb from around twenty-four weeks of gestation, and is born already familiar with the rhythm and prosody of their native language, their parents' voices, and sounds that were prominent in the intrauterine environment. The newborn hearing screening test (offered to all UK newborns) identifies significant hearing impairment early; the first year of life is a critical sensitive period for auditory development and language acquisition.
By six months babies respond to their name and show clear startle responses to sudden loud sounds. By twelve months they respond to quiet sounds across the room and are actively turning to locate sources of sound. Hearing concerns — the baby who does not startle, does not respond to voice, or who is significantly delayed in babbling — should always be followed up with formal audiological assessment.
Touch and Proprioception
Touch is well developed at birth — the newborn responds to gentle touch, to temperature, and to pain. The proprioceptive system — which gives the body a sense of its own position and movement — is already functional and is stimulated by being held, carried, rocked, and moved through space. This proprioceptive input is calming and regulating for infants, which is why movement-based soothing (rocking, swaying, walking) works so effectively.
Tactile experience through play — sand, water, playdough, varied textures — continues to develop and refine the sensory processing systems throughout the toddler years.
The Vestibular System
The vestibular system in the inner ear provides the sense of balance and spatial orientation. It develops through movement — being carried in different positions, rolling, crawling, sitting up, spinning, and the eventual transition to upright walking. Physical play that involves movement in multiple planes (swinging, rolling, climbing) provides rich vestibular input that supports postural control, coordination, and eventually balance.
Sensory Sensitivity
Some children show unusual responses to sensory input — either hypersensitivity (strong aversive reactions to sounds, textures, lights, or tastes) or hyposensitivity (seeking more sensory input than typical, apparently not noticing pain, craving vigorous physical sensation). Either pattern, when it significantly affects everyday functioning, is worth discussing with a health visitor or GP, as sensory processing differences can be a feature of autism, developmental coordination disorder, or other conditions that benefit from early support.
Key Takeaways
The senses — vision, hearing, touch, proprioception, vestibular, taste, and smell — are present but immature at birth and develop rapidly over the first three years. Sensory experience is not merely pleasant for babies and toddlers but neurologically essential: it drives the formation of neural connections during a period of extraordinary brain plasticity. Vision and hearing are the senses most amenable to early assessment, and early identification of sensory impairment is important because interventions are most effective when begun in the sensitive periods of sensory development.
