Older adulthood can be divided into three periods: young-old (60-69), middle-aged-old (70-79), and old-old (80-89). Physically, the body undergoes declines in most major systems as a result of earlier life events and lifestyle choices. Mentally, cognition and reaction time slow although dementia is not normal aging. Personality development focuses on adjusting to retirement, family/social roles, and government policies around increasing lifespans.