Two negative emotions experienced during early childhood are fear
(anxiety) and aggression
Preschool children probably become fearful because of their remarkable fantasy life, and their inability to distinguish between reality and pretending. Childhood fears are usually temporary; these fears normally disappear with time. Preschoolers (ages 2–6) are typically afraid of animals, bodily injury, dark places, loud noises, strangers, and being separated from their parents. Although childhood fears are normal and to be expected, exaggerated or chronic fears should be evaluated by a professional.
Childhood aggression has been a topic of intense study in recent decades. Aggression, which appears by ages 2 or 3, may involve an intentional action to harm another (such as biting another child) or directed hostility to attain particular goals (such as taking a toy from another child). Fortunately, most children become less aggressive at about age 6. Preschoolers probably develop aggression in response to their egocentric perspective. Anyone or anything that frustrates egocentric children by preventing them from getting what they want is likely to trigger a hostile response. The male hormone testosterone may also explain why males are more likely than females to exhibit aggressive behavior. As with childhood fears, exaggerated or chronic aggression should be evaluated by a professional.