Final answer:
The model developed by Paul and Margret Baltes focusing on the changes and losses in late adulthood is the selective optimization with compensation theory, which highlights personal development through adaptation to aging.
Step-by-step explanation:
The model of successful aging developed by Paul and Margret Baltes is known as selective optimization with compensation. This theory is grounded in the belief that successful development and mastery of everyday life challenges throughout the life course rely on the interplay of selection, optimization, and compensation. In the context of aging, selective optimization with compensation addresses the balance between the losses experienced due to aging and the gains made by focusing on specific, individual goals. It acknowledges that aging involves changes and losses in capabilities, but emphasizes adaptation and personal development, rather than decline.