3 Months and Up
Starting at around 3 months of age, your baby's motor skills will improve, and he'll figure out all the fun things he can do with his body: roll over or kick at a dangling toy. The previous "good or bad" world of emotional experience is deepening and widening. These new emotions include curiosity ("Wow, I could stare at my hands all day!") and surprise ("Where's Mom? There she is! Peekaboo is fun!"). In addition to increased physical skills, cognitive skills have advanced to the point where he can set goals. This growing emotional intelligence allows him to feel the joy of success or the frustration of failure. Consider an 8-month-old whose hands are reaching toward a desired toy. "If you stop a baby from trying to get something, that is going to make him mad," says Susanne A. Denham, PhD, author of Emotional Development in Young Children (Guilford Press). "They have a goal, and they do not like that you're keeping them from it."
Fear is another emotion that appears before a child's first birthday, usually in conjunction with stranger anxiety. This new emotion is another sign of higher thinking. "It's hard to be afraid of a stranger if you can't figure out whom you recognize," Denham says.