Parents do not always give money to their adult children out of pure altruism. Studies have shown that the traditional idea of parents giving money to their children based on their income is not always true. Parents actually consider their children's future income when deciding how much money to give. This means that past studies may have been too limited in their approach. Additionally, the amount of money parents give can change over time, and is often linked to how much money their children are making at that moment. This shows that dynamic models can help us understand why parents give money to their adult children better than static models.