Age-related cognitive decline begins in early adulthood, according to a study published in Neurobiol Aging. The research suggests that cognitive performance declines with age, even in young adults aged 18 to 60. However, cross-sectional studies may overestimate age-related decline because they do not account for prior test experience, which can improve performance. Longitudinal studies, which track the same individuals over time, show less decline, indicating that retest effects may distort cross-sectional results. The study found that cognitive decline begins in the 20s and 30s, as evidenced by neurobiological variables such as brain volume, myelin integrity, and cortical thickness, which show age-related declines starting in early adulthood. These findings challenge the notion that cognitive decline begins later in life. The study also highlights the importance of considering retest effects when interpreting longitudinal data, as they can significantly influence results. Overall, the research indicates that cognitive decline begins relatively early in adulthood, and that longitudinal comparisons may underestimate the true age-related changes in cognitive functioning.Age-related cognitive decline begins in early adulthood, according to a study published in Neurobiol Aging. The research suggests that cognitive performance declines with age, even in young adults aged 18 to 60. However, cross-sectional studies may overestimate age-related decline because they do not account for prior test experience, which can improve performance. Longitudinal studies, which track the same individuals over time, show less decline, indicating that retest effects may distort cross-sectional results. The study found that cognitive decline begins in the 20s and 30s, as evidenced by neurobiological variables such as brain volume, myelin integrity, and cortical thickness, which show age-related declines starting in early adulthood. These findings challenge the notion that cognitive decline begins later in life. The study also highlights the importance of considering retest effects when interpreting longitudinal data, as they can significantly influence results. Overall, the research indicates that cognitive decline begins relatively early in adulthood, and that longitudinal comparisons may underestimate the true age-related changes in cognitive functioning.