Infants Can See Image Differences That Adults Cannot, Study Finds

Babies may be able to see image details that are invisible or imperceptible to adults. According to a recent study [PDF] from Japanese scientists Jiale Yang, So Kanazawa, Masami K. Yamaguchi, and Isamu Motoyoshi, three- and four-month-old infants may view certain images differently because they lack perceptual constancy. That means they can see small image differences that are invisible to adults because of changes in lighting conditions.

For example, when adults see the same objects in different lighting, their brains automatically adjust to those lighting conditions. If your friend steps in front of a blue spotlight, they might appear blue, but you still recognize them. That’s perceptual constancy in action: Your brain recognizes that, though your friend is bathed in blue light, they aren’t suddenly a totally different blue person. Young babies who haven’t yet developed perceptual constancy, meanwhile, are able to see subtle images differences that adults ignore, but may be unable to recognize the same objects in different light.

In the study, 42 babies between three and eight months old looked at images rendered from 3D objects like snails and teapots. Since the babies were pre-verbal, scientists tracked their eye movements to determine how they interacted with the images. According to Scientific American, previous studies have shown that infants spend more time looking at new objects than those they’ve seen before, so the scientists in the study measured infant recognition of different objects by recording how long they looked at each image. They found that infants up to four months old recognized image differences caused by changes in illumination that weren’t visible to adult viewers. At five months old, however, the infants lost that ability, and by seven or eight months, began to develop perceptual constancy.

Current Biology

In the above image, for example, adults generally see snails A and B as the most similar because of their glossy finish. In reality, B and C are most similar with regards to pixel intensity—a characteristic that three- and four-month-old infants recognized.

According to the scientists, “These findings support the notion that acquiring perceptual constancy leads to a loss of sensitivity to variant information, which is negligible for constant surface material perception.”

That is, as we develop, we lose the ability to see certain information, but that loss makes it easier for us to understand the world around us. As Scientific American explains, “The loss of sensitivity to variant information that we all experienced as babies created an unbreachable gap between us and the physical world. At the same time, it served to tune our perception to our environment, allowing us to navigate it efficiently and successfully.”