Violation of expectation research was conducted by Baillargeon in order to see whether young infants actually have object permanence (i.e. they know that objects out of sight still exist), but are unable to search for them because they do not have the necessary motor abilities. The violation of expectation technique is based on the idea that infants will show surprise when witnessing an impossible event. For example, in one study, infants were shown a large or small carrot moving along a track and passing behind a screen with a window in it. It should have been possible to see the large carrot pass by the window, but not the small one. Infants as young as three months old showed surprise when they saw the impossible event (e.g. the large carrot did not appear in the window) but not when they saw the possible event (small carrot did not appear).