Your Brilliant Baby in Week 24: Using Primitive Arithmetic

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Baby's Brain in Week 24

Although it's only the basics, babies at six months actually add and subtract. Ok, not in the abstract sense of two plus one equals three, or three minus one equals two. They don't get numerals or plus, minus, and equal signs—even though we do know your smart child pays attention to some number patterns already.

But when a baby sees two objects and then watches as one is taken away, she expects to see one remaining. If the situation is different than what she expects, she looks perplexed. Incredible, right?

Here's how the researchers discovered this phenomenon to be true: Five- month-old infants first saw two objects, say a cup and a glass; then an opaque screen covered the objects. Next the babies watched as an experimenter proceeded to either add another object to the ones behind the screen, or remove one. When the researcher removed the screen to reveal the one added or subtracted item, each baby was interested but somewhat blasé, as they were expecting exactly what they now saw.

If, however, the researcher was able to work quickly and sneak one item away or add one without the baby seeing him do so, and remove the screen revealing one more or one less item than the baby was expecting, each infant looked longer at this situation. Researchers believe this indicates that what the babies were seeing was not what they were expecting, and the children were therefore perplexed. If they saw one item added to a two-item display, they expected to then see three items as before, not one.