The impact of copying error on change in artifact morphology is studied through a field experiment with three groups of potters, each with a distinct potting tradition (one from France and two from India). The nine French potters and the 12 Indian potters had to reproduce – in five specimens – four different model shapes with two different weights of clay (in total, each potter threw 40 pots). Results show that the variability generated while copying depends on both the difficulty of the task and the cultural learning niches of the potters. We conclude that, even though unintended, the copying error is culturally constrained and therefore its amplitude and directions predictable. This is attributed to the cultural selection of motor skills during apprenticeship.