FIGURE 7.7 Infants’ understanding of addition On the task used by Wynn (1992) to examine whether infants have a rudimentary grasp of addition, 5-month-olds saw (1) a single doll placed on a stage, (2) a screen raised to hide the doll, (3) a hand with a doll in it move toward and then behind the screen, and (4) the hand return empty after having been behind the screen. Then the screen dropped, revealing either the possible event of two dolls on the stage (5 and 6) or the seemingly impossible event of one doll on the stage (5* and 6*). Infants younger than 6 months looked for a longer time at the seemingly impossible event, suggesting their surprise at seeing one doll rather than two.