Once an infant is able to expect the enjoyment of having an object, such as a toy, he will be enraged by being deprived of it. If he is accustomed to pleasurable experiences, such as being rocked in a swing or observing his mother s approach, he will be angered if they are denied him. Anger ensues from instances where expectations of pleasurable events are violated, or what we call frustration. So infants old enough to have expectations are also old enough to be frustrated and to get angry. Now consider the situation where an infant does not express anger and has not been frustrated.
Jealousy works in much the same way.
Frustrated expectations precipitate jealousy just as they might precipitate anger. In the case of jealousy, however, the expectations associated with jealousy are specifically related to what psychoanalysts have named a love object, such as a spouse or parent, and how she gives out attention to other individuals. This holds true for adults as well as infants. Infant jealousy is usually a response to a parent s directing attention toward a sibling. Firstborn children are upset by this because they develop the expectation of receiving exclusive parental attention since there are no other children present during the course of the day.