Babies, like all humans, cannot see infrared light. The human eye is not equipped to detect this type of electromagnetic radiation. Human vision is limited to a specific range of the electromagnetic spectrum, and this holds true from birth throughout life.
Understanding Infrared Light
Infrared (IR) light is a form of electromagnetic radiation with wavelengths longer than visible light but shorter than microwaves. It starts just beyond the red end of the visible spectrum, with wavelengths typically ranging from about 700 nanometers to 1 millimeter.
Many everyday objects emit infrared radiation, often perceived as heat. Common natural sources include the sun and fire. Artificial sources include heating devices, remote controls, and night vision technology. Despite its pervasive presence, infrared light is undetectable by the unaided human eye.
The Limits of Human Vision
The inability of humans to see infrared light stems from the specific design of our eyes, particularly the photoreceptor cells located in the retina. The retina contains two main types of photoreceptors: rods and cones. Rods are responsible for vision in low light and detect shades of gray, while cones are active in brighter conditions and enable color vision.
These photoreceptors are sensitive only to a narrow band of the electromagnetic spectrum, known as the visible spectrum. This range typically spans wavelengths from approximately 400 nanometers (violet) to 700 nanometers (red). Infrared light falls outside this range because its wavelengths are too long for the proteins within our photoreceptors to absorb and convert into electrical signals the brain can interpret as vision.
How Infant Vision Develops
While babies cannot see infrared light, their ability to perceive the visible world undergoes significant development during their first year. At birth, an infant’s vision is quite blurry, estimated to be around 20/200 to 20/400, and they primarily see in black, white, and shades of gray. Newborns focus best on objects about 8 to 12 inches away, which is roughly the distance to a parent’s face during feeding. They are particularly drawn to high-contrast patterns and faces.
Between one and three months, babies begin to distinguish some colors, with red and green often being the first hues they perceive, and their eyes start to work together more effectively, enabling them to follow moving objects. By four to six months, an infant’s vision sharpens considerably, and they can typically see a full spectrum of colors with improved clarity. Depth perception also develops more fully around five months, allowing them to better judge distances and reach for objects. By eight to twelve months, a baby’s vision approaches near-normal adult levels. They become adept at tracking and grasping objects as they begin to crawl and stand.