Infants often exhibit a consistent lateral preference, favoring looking or holding their head to one side. This tendency, where a baby is seemingly “always on my right side,” results from a complex interaction of the caregiver’s habits, the baby’s developing sensory system, and physical development. Understanding these reasons can help parents ensure their child’s comfort and healthy development.
The Role of Caregiver Dominance and Holding Patterns
The typical tendency across the general population is a “left-cradling bias,” where most caregivers hold the infant on their left side, regardless of their dominant hand. This positioning places the baby’s head near the caregiver’s heart, which was once thought to be a pacifying factor, though that theory has been largely dismissed. Research suggests this bias relates to the right hemisphere of the brain, which specializes in processing emotional and social information. Holding the baby on the left channels the child’s sensory input more directly to the caregiver’s right hemisphere, potentially improving emotional monitoring.
If a baby is consistently held on the right side, it often points to a functional necessity specific to the caregiver. A right-handed caregiver might use their less-dominant left arm to hold the baby, freeing their dominant right hand for tasks like preparing a bottle or opening doors. Conversely, a left-handed caregiver naturally uses their non-dominant right arm for cradling, placing the baby on the right side. Additionally, the specific way a caregiver bottle-feeds or breastfeeds can establish a strong habit of consistent positioning.
This consistent side preference, while comfortable for the caregiver, can inadvertently encourage the infant to develop a habitual head turn toward the center of the caregiver’s body. The baby may be positioning themselves to look up at the caregiver’s face or to access the bottle or breast from that specific angle. Over time, this repeated positioning can create a fixed preference for looking in that one direction.
How Sensory Input Drives Head Preference
The infant’s developing brain constantly seeks and processes social information, driving a preference for turning their head in a specific direction. Since infants are highly attracted to human faces, they position themselves to optimize this visual experience. The human brain, even in infancy, processes social cues with lateral asymmetry.
Some studies suggest that infants display a preference for looking at faces with their left visual field, which projects to the right hemisphere of the brain. This neurological bias prompts the infant to turn their head so the caregiver’s face falls into that preferred visual field. When an infant is held on the right side, they naturally turn their head toward the caregiver’s face, which is a powerful social stimulus.
The baby’s positioning may also be a response to auditory input, as they try to orient themselves toward the source of the caregiver’s voice or breathing patterns. The infant’s desire to look at a face, combined with the consistent position in which they are held, creates a powerful feedback loop. The baby turns their head to the right to see the face, and the caregiver reinforces this position by holding them there, establishing a pattern that looks like a fixed preference.
Developmental Causes of Fixed Preference
When a head preference becomes difficult to change, it often signals a physical or motor development issue rather than just a habit. While a fixed preference can stem from a simple positional comfort adopted in the womb, a stronger, more persistent preference may indicate congenital muscular torticollis (CMT).
CMT is a condition where the sternocleidomastoid (SCM) muscle in the neck is shortened or tight, making it difficult for the baby to turn their head fully to the opposite side. This muscle tightness is often present at birth and causes the baby’s head to tilt to one side while the chin rotates to the opposite shoulder. Because turning the head to the non-preferred side is restricted or uncomfortable, the baby avoids it, reinforcing the preference for the easy side.
A consistent head preference, whether positional or due to CMT, can lead to deformational plagiocephaly, commonly known as a flat spot on the head. Because the infant’s skull is soft and pliable, prolonged pressure on one area while lying down (such as in a car seat or swing) results in noticeable flattening. This condition is estimated to co-exist with torticollis in up to 90% of cases.
To prevent or manage this, caregivers should encourage “tummy time” while the baby is awake and supervised, as this strengthens neck and upper body muscles and relieves pressure on the skull. It is important to seek a professional evaluation from a pediatrician or pediatric physical therapist if the baby consistently struggles to turn their head or tilts it to one side. Early intervention is highly effective; for instance, 98% of infants diagnosed with CMT before one month of age achieve a normal range of motion within six weeks of beginning physical therapy.