Winnicott’s overall claim is that previous theories about the roots of aggression fail to account for lessons about destruction that are learned during the object use phase.

He explains that as babies, individuals discover that objects can stay the same despite attempts to destroy them. For instance, consider how he uses the example of breastfeeding. Babies may bite or tug while breastfeeding, but it does not stop them from being able to receive milk. When mothers react calmly to such scenarios, it helps the child begin to understand the world is a safe place.

Winnicott asserts that this understanding of destruction is an essential aspect of human development and is important in developing object constancy. He writes that when individuals are properly supported and cared for during this period “there is no anger in the destruction of the object” (125). Instead there is “joy at the object’s survival” (125). Children who are supported through this phase develop healthy concepts of destruction that tend to exist in fantasy.

However, Winnicott also explains that when children are not guided through this phase well, they can develop problems with aggression. He claims that babies who have not been properly supported during this phase cannot “encompass” aggression (125). For example, some parents do not tolerate any anger or destructive impulses from children, but these behaviors are necessary to learn about the world. Discouraging children’s exploration of their environment may cause these children to be ashamed or afraid of their own anger. As a result, they may grow up struggling with how to express aggression and may express this by acting out at inappropriate times.