For example, if a baby sees two toys being put in an empty box, then three toys taken out of the same box, the baby gets surprised and looks longer at this event than at two toys being removed. So measuring looking time can help us discover babies’ expectations about certain events and the outcomes that violate these expectations. During a looking time study we typically show babies some simple videos on a screen. To get an exact looking time measure, we record the baby’s face on video during the session.