Children’s Use of Everyday Artifacts: Learning the Hidden Affordance of Zipping

The everyday world is populated with artifacts that require specific motor actions to use objects as their designers intended. But researchers know little about how children learn to use everyday artifacts. We encouraged 44 12- to 60-month-old children to unzip a transparent pouch to retrieve a small toy during a single 60-second trial. Although unzipping a pouch may seem simple, it is not. Preliminary kinematic data from 6 adults showed that unzipping requires a set of precise role-differentiated bimanual actions—one hand must stabilize the pouch below the slider while the other hand applies a pulling force on the tab opposite to the first hand and parallel to the direction of the teeth. The tolerance limits for applying the forces are relatively narrow (stabilizing the pouch within 4 cm of the slider while pulling the tab within 63° of the zipper teeth). Children showed an age-related developmental progression for the unzipping action. The youngest children did not display the designed pulling action, older children pulled the tab but applied forces outside the tolerance limits (failed to stabilize the pouch in the correct location, pulled in the wrong direction), and only the oldest children successfully implemented the designed action. Findings highlight the motor requirements in children’s discovery and implementation of the hidden affordances of everyday artifacts.