Final answer:
A child considering herself a loser for forgetting to buy movie tickets is engaging in personalization, a cognitive distortion where an individual attributes external events to themselves, negatively affecting their self-esteem.
Step-by-step explanation:
The child who calls herself a loser because she forgot to buy movie tickets and thinks that this mistake means that she is worthless is engaging in a cognitive distortion known as personalization. This is one example of a broader category of cognitive distortions or irrational thought patterns that can lead to negative emotions and behaviors, and it fits within the scope of cognitive-behavioral theories in psychology. Another possible term to describe her thinking might be overgeneralization, where a person takes a single event and generalizes it to their entire self-concept.
It's important for that child to understand that making a mistake does not define her worth as a person. Instead, everyone makes mistakes, and it's part of the human experience. It's how we respond to our mistakes that helps us grow and develop resilience.