Around 5-6 months of age, infants begin looking for hidden objects. Around 7 months, they start to become much better at reaching reliably towards objects they want. Infants seem like they are on a steady march to become better and better at finding and grabbing objects. However, around 8-12 months, infants make a curious mistake. That brings us today’s blog post: the A-not-B Error.
Jean Piaget, the father of cognitive development, did most of his research on his three kids in the early 1900s. Although his theories are no longer in vogue, he is still revered today for the clever tasks he dreamed up for examining how young children think. The Piagetian search task is one of those simple clever tasks. Basically you have two hiding locations (we’ll call them location A and B) and you start off by showing the child that you are hiding a desirable toy in location A. After a pause (just a few seconds), you allow the child to search. Typically around 8-9 months of age, infants readily search in location A and retrieve the toy. Then with the child watching, you clearly hide the toy in location B. After a pause, you allow the child to search. That’s when you see it… the A-not-B error. See cogscibaby in action below!
At the time of the video, cogscibaby had just turned 9 months old.
The nice thing about this error is that it is pretty reliable! So grab a 9-10 month old near you and try this baby trick at home!