Suppose you observe a baby sitting in front of a mirror. You now place a dot of rouge on the baby's nose. You see the baby look at the mirror, and then he crawls around the mirror to find the baby on the other side. Your best guess is that this baby is about how old?
◦ about 6 months of age
◦ about 12 months of age
◦ about 18 months of age
◦ 24 months of age