Overall cognitive status can vary across an individual's life span in response to factors that promote either positive or negative neuroplasticity. Positive neuroplasticity refers to the physiological ability of the brain to form and strengthen dendritic connections, produce beneficial morphological changes, and increase cognitive reserve. Negative neuroplasticity refers to the same physiological ability of the brain to atrophy and weaken dendritic connections, produce detrimental morphological changes, and decrease cognitive reserve. Factors that promote positive neuroplasticity include physical activity, education, social interaction, intellectual pursuits, and cognitive remediation. Factors that promote negative neuroplasticity include poor health, poor sleep hygiene, poor nutrition, substance abuse, and depression and anxiety. Implications for promoting positive neuroplasticity and avoiding negative neuroplasticity across the life span are emphasized to facilitate optimal cognitive health and ensure successful cognitive aging.