What triggers Riley's first core memory?

Riley’s first core memory is triggered by scoring a hockey goal.

As a young child, Riley joins her parents on the ice and accidentally—or instinctively—scores her first goal. The moment makes her feel joyful and connects her with her family, producing a glowing yellow core memory in Headquarters.

That memory does more than record an exciting event: it powers Hockey Island, which represents Riley’s love of the sport and an important part of her personality. The sequence introduces the film’s central idea that emotionally significant memories help shape identity.

The film later complicates this simple model. Memories can change emotional color when Sadness touches them, and Riley eventually forms a core memory combining happiness and sadness after being comforted by her parents. Thus, the hockey goal is the first clearly shown core-memory event, while later memories demonstrate that meaningful experiences are not always purely happy.