Prenatal Form and Function – The Making of an Earth Suit

Learning Before Birth

We know that infants learn: what we don't know is how early and what they learn. Obviously, testing newborns to resolve these questions can pose some problems. They can't fill-in-the-blanks or answer questions. Therefore, researchers have to develop ingenious methods to discern newborn knowledge, making use of normal and observable infant behavior. Researchers test infant knowledge by testing expectations. If a baby has learned about something, he will have certain expectations about what will occur in a situation. If something different occurs, the infant will be surprised. Researchers determine infant surprise by measuring gaze length: keeping track of how long an infant focuses on something before looking away. If the baby is surprised, he or she will stare at something longer than normal. Infants also look at new things longer than they look at familiar things. Researchers use this phenomenon to determine whether an infant recognizes a portion of a story previously heard, by checking to see if the infant reacts to it as if it were a new event.

The amount of time this captivated baby spends staring at her toy is probably proportional to how familiar she is with the toy.

Researchers also test preferences. One way researchers test a newborn's preference is through "non-nutritive sucking." Here the researchers rig up a device attached to a pacifier which measures the intensity with which the infant sucks. Infants even only a few days old quickly learn the cause and effect relationship between their sucking and the stimulus. In one example, if the infant sucked at a certain rate, he heard a passage read in Spanish: if he sucked at a higher rate, he heard an English passage. In this way, an infant can control what she hears or sees, and therefore, researchers can determine what the infant prefers.

¹ Kyra Karmiloff and Annette Karmiloff-Smith, Pathways to Language: From Fetus to Adolescent (Cambridge: Harvard, 2001), 14-17.