These themes could be described in a variety of ways and other themes could be added to the list. Regardless of how one describes the core principles of attachment theory, the key insight is that the same principles of attachment apply to close relationships throughout the lifespan. The principles of attachment in adult relationships are fundamentally the same as the principles of attachment between children and their caregivers. Some researchers, however, have criticized the theory of attachment in adult relationships and claim that adult attachment theory is simply an assumption that the principles of attachment during childhood continue to have an effect on an individual in adulthood.