Most children start counting after the age of two, after observing much tallying done by parents, siblings and television characters. By watching others count, 18-month-old babies acquire a sense of numbers long before they can speak, according to a study by Michael Siegal of the University of Sheffield in England. The babies heard a voice counting up to six as the video showed a hand either pointing to six fish in turn or moving between two of the fish. They spent more time looking at the sequence showing correct counting, indicating that they preferred it and, therefore, knew how to keep score. “Infants are much more aware of objects than we give them credit for,” Siegal says.