Happiness and Anger
"Babies coo early on -- which is how we think that they are feeling well," says Dr. Cole. "Out of this eventually come a smile and a laugh." While a newborn's "smiles" are the result of involuntary neurological activity, at around 3 months of age babies typically develop a "social smile." Instead of their smile being the result of an internal state, babies can now react to external stimuli -- particularly faces, which babies this age love to look at, says Dr. Cole. "An important milestone is when babies are smiling in relation to someone and coordinating their behavior with the other person's." What form does this take? Usually, a face-to-face "conversation" with a caregiver in which the baby coos, the caregiver responds (perhaps by smiling and saying something like, "Yes, you are happy!"), and the baby responds by smiling and cooing some more.
A wailing, red-faced baby may seem angry, but is that an accurate assessment of what he's feeling? Maybe not. What adults might see as anger, a very young baby (under 6 months) feels as the sensations of an unpleasant state -- he could be wet, hungry, or tired, for example. During the first six months of life, it's important for a baby to discover that when he has these sensations -- which will later become emotions -- things will get fixed. Discovering this helps give him a sense of security.
In order to reach the point where they can feel anger as adults do, babies have to go through a building-block process in which they develop the experience and expectations to feel anger and frustration. Between 3 and 6 months, babies are gaining experience with relationships and objects in the world, and as their memories develop, they begin to form expectations of what they think will happen. For example, experience may tell a baby "When I can't reach the ball, Mommy will roll it toward me." If, for some reason, Mommy is delayed in handing over the ball, baby might get angry. "When babies form expectations about what is supposed to happen and it doesn't happen, then they experience distress from not getting what they want," explains Dr. Cole.