Complex ThoughtsOld thinking: Children don't start to have complex thoughts until the preschool years.
New thinking: High-level comprehension may begin as early as 3 months.
Remember the Sesame Street song "One of These Things (Is Not Like the Other)"? The tune teaches categorization, which involves observing specific features and then noting them in other objects. (Both the blocks and the fire engine are red, for example.) Your 3-month-old could play a version of that game. Researchers at Birkbeck University of London found that 3-month-olds were able to recognize the difference between dogs and cats. When shown a picture of a dog after viewing several cats, the babies in the study looked longer at the dog, a signal that they recognized something different about the object.
What's more, at 6 months a baby can detect differences in a counting sequence. After hearing a tone matched with an object just a few times (the baby sees two objects, hears two tones), a 6-month-old can tell when the number of tones doesn't match the number of objects.
What it means for you: No need to buy those flash cards yet (if ever) -- your baby's brain is fertile ground as is. Even if he can't sort blocks by himself, he might enjoy watching you put all the blue blocks in one pile and the red in another. You can also count them, build with them, or arrange them from smallest to largest.
Old thinking: Boys and girls are similar at birth; their differences emerge as they grow.
New thinking: Although social forces play a role, boys and girls seem to be hardwired differently.
Research has shown that -- much like adult men and women -- boys who are 6 to 8 months old enjoy group interactions, while girls this age prefer individual encounters. When researchers measured how long babies looked at videos of puppets, they found that girls spent more time on a single puppet, while boys directed their gaze at groups.
Studies have also shown that while newborn boys and girls make a similar amount of eye contact with adults, over the next four months girls steadily increase eye contact, but boys progress more slowly.
What it means for you: Don't be surprised if your little girl is less delighted by her first playgroup than some of the boys in the room. Consider helping her to focus on one or two babies or objects rather than introducing her to everyone at once. As for your boy, you may find that he's more stimulated by the playgroup than by single playdates at home. At the same time, remember that while gender differences can help make sense of some behaviors, it's important to respond to your baby's unique personality.