Final answer:
Middle-aged individuals are most likely to report declines in life satisfaction, according to Rocke and Lachman (2008), while older adults often experience higher levels of happiness.
Step-by-step explanation:
According to Rocke and Lachman (2008), middle-aged individuals are most likely to report declines in life satisfaction. This finding may be associated with various life challenges often occurring during midlife, such as career plateauing, changes in family dynamics, and the onset of health issues. In contrast, research such as by Levy et al. (2002) and expert opinions by professionals like Louise Aronson, MD, suggest that older adults often report higher levels of happiness and satisfaction, reflecting positive self-perceptions of aging and likely benefiting from the resolution of earlier life-stage challenges.