Yes, babies can get goosebumps, but the timing and effectiveness of this reflex differ from the response seen in adults. Goosebumps, scientifically known as piloerection, occur when the tiny hairs on the skin stand upright, causing the characteristic bumpy texture. This involuntary reaction serves a purpose related to physical survival and emotional response.
The Physiology Behind Goosebumps
Goosebumps are caused by a reflex action involving a small, smooth muscle called the arrector pili. This muscle is attached to the base of every hair follicle. When the muscle contracts, it pulls the hair follicle upright, causing the surrounding skin to slightly elevate and form the small bump.
This process is controlled by the sympathetic nervous system, the branch of the autonomic nervous system responsible for the involuntary “fight-or-flight” response. Sympathetic nerves release neurotransmitters that signal the arrector pili muscles to contract. Contraction is a reaction to physical stimuli, such as a drop in temperature, or to strong emotional states like fear. This ancient mammalian mechanism was meant to trap a layer of warm air close to the skin for insulation in fur-covered ancestors.
Developmental Timeline of the Goosebump Reflex
The physical structures necessary for piloerection—hair follicles, arrector pili muscles, and sympathetic nerves—are fully formed in a newborn. However, the neurological system controlling the reflex is still maturing after birth. Therefore, the reflex function is often inconsistent or unreliable during the first few weeks of life.
The autonomic nervous system, which governs all involuntary responses, continues to develop rapidly throughout the first year. This maturation is why many primitive reflexes, such as the Moro or startle reflex, disappear within the first few months as the central nervous system gains more control. While piloerection persists into adulthood, its consistent appearance often aligns with the general neurological maturation occurring over the first several months.
Infants may exhibit the reflex in response to cold from birth, but it becomes more robust and reliably triggered by the time they are several months old. Due to the developing nervous system, the infant’s response is generally limited to the physical trigger of cold exposure. Complex emotional triggers, which affect adults, become linked to the reflex later in childhood.
Goosebumps and Infant Thermal Regulation
In the context of cold, the goosebump reflex attempts to provide insulation by raising the hair to create an air layer. However, this mechanism is largely ineffective in babies due to their sparse body hair. The presence of goosebumps is therefore significant as a sign that the baby’s body is actively responding to cold stress.
Infants are highly susceptible to heat loss because they have a significantly larger surface area-to-volume ratio compared to adults. They lose heat to the environment much faster relative to their body mass. Their thin skin and low amount of subcutaneous fat also provide little thermal insulation.
When a baby is cold, their primary defense is non-shivering thermogenesis, not goosebumps or shivering (which is often absent in newborns). This process involves metabolizing brown adipose tissue, or “brown fat,” concentrated around the neck, shoulders, and back, to generate heat. Goosebumps are a clear indication that the body is struggling to maintain core temperature. Caregivers should immediately take action, such as adding layers of clothing or adjusting the room temperature.