UNIT 9

• Biological Theories of Aging

  • Evolutionary Theory of Aging
  • Cellular Clock or Telomere Theory
  • Free-Radical Theory
  • Mitochondrial Theory
  • mTor Pathway Theory
  • Hormonal Stress Theory
• Evolutionary Theory of Aging


  Natural selection has not eliminated many harmful conditions and nonadaptive characteristics in older adults
• Cellular Clock or Telomere Theory


  Leonard Hayflick's (1977) theory that cells can divide a maximum of about 75 to 80 times, and that as we age our cells become less capable of dividing
• Free-Radical Theory

  People age because when cells metabolize energy, the by-products include unstable oxygen molecules known as free radicals. The free radicals ricochet around the cells, damaging DNA and other cellular structures. The damage can lead to a range of disorders, including cancer and arthritis.
• Mitochondrial Theory

  Aging is due to the decay of mitochondria, primarily caused by oxidative damage and loss of critical micronutrients supplied by the cell
• mTOR Pathway Theory

  mTOR pathway has a central role in the life of cells, acting as a cellular router for growth, protein production/metabolism, and stem cell functioning
• Hormonal Stress Theory


  Aging in the body's hormonal system can lower resistance to stress and increase the likelihood of disease
• The Shrinking, Slowing Brain
• Healthy aging brain

  • Decrease in brain volume due mainly to shrinkage of neurons, lower numbers of synapses, reduced length and complexity of axons, and reduced tree-like branching in dendrites, but only to a minor extent attributable to neuron loss
  • General slowing of function in the brain and spinal cord begins in middle adulthood and accelerates in late adulthood
  • Aging has also been linked to reduced synaptic functioning and decreased production of some neurotransmitters, including acetylcholine, dopamine, and gamma-aminobutyric acid (GABA)
• Neurogenesis


  Occur in human adults but only in two brain regions: hippocampus and olfactory bulb
• The Adapting Brain
• Physical Appearance and Movement
• Physical changes in late adulthood


  • Both men and women become shorter due to bone loss in their vertebrae
  • Weight usually drops after 60 years of age due to muscle loss, giving a "sagging" look
  • Older adults move more slowly than young adults, and this slowing occurs for movements with a wide range of difficulty
• Sensory Development
• Visual decline in late adulthood


  Linked to cognitive decline and having fewer social contacts and engaging in less challenging social/leisure activities
• Diseases of the Eye

  • Cataracts
  • Glaucoma
  • Macular degeneration
• Hearing decline


  Much greater in individuals 75 years and older than in individuals 65 to 74 years of age
• Health Problems
• Most common chronic disorders in late adulthood

  Arthritis is the most common, followed by hypertension
• Cognitive Functioning in Older Adults
• Cognitive Mechanics


  • Speed and accuracy of the processes involved in sensory input, attention, visual and motor memory, discrimination, comparison, and categorization
• Cognitive Mechanics


  Some researchers conclude that the decline may begin as soon as early midlife
• Cognitive Pragmatics


  Reading and writing skills, language comprehension, educational qualifications, professional skills, self-understanding, and life skills that help us to master or cope with challenges. May actually improve, at least until individuals become very old.
• Speed of Processing


  It is now well-accepted that the speed of processing information declines in late adulthood, likely due to a decline in functioning of the brain and central nervous system
• Attention

  Older adults may not be able to focus on relevant information as effectively as younger adults, and are less able to ignore distracting information, especially as attentional demands increase
• Memory


  Aging is linked with a decline in explicit memory, while implicit memory is less likely to be adversely affected. Older adults think they can remember older events better, but researchers find the older the memory, the less accurate it is. Ability to retrieve very specific information (such as names) usually declines.
• Decision Making


  Despite declines in memory, many older adults preserve decision-making skills reasonably well, though they may be more inconsistent in their choices. Age-related decreases in memory can impair decision making in some cases.
• Metacognition


  Older adults tend to overestimate the memory problems they experience and become more anxious about minor forgetfulness than younger adults
• Language Development

  Vocabulary often continues to increase throughout most of the adult years, but some decrements in language skills may appear in late adulthood. Older adults may have difficulty retrieving words and understanding spoken language in certain contexts. Their speech is typically lower in volume, slower, less precisely articulated, and less fluent, but adequate for everyday communication.
• Cognitive ability


  One of the best predictors of job performance in older adults. Older workers have lower rates of absenteeism, fewer accidents, and higher job satisfaction than their younger counterparts.
• Adjustment to Retirement
• Factors affecting retirement adjustment

  • Older adults who adjust best are healthy, have adequate income, are active, are better educated, have an extended social network including both friends and family, and were satisfied with their lives before retirement
  • Older adults with inadequate income and poor health, and those who must adjust to other stress that occurs at the same time as retirement, have the most difficult time adjusting
• Mental Health
• Depression in older adults

  Not more common and not more often caused by psychological factors, but more likely to be chronic, linked to higher rates of medical problems. Common predictors include earlier depressive symptoms, poor health, disability, losses, low social support, and social isolation.
• Older adults who successfully adjust to retirement


  • Come
  • Are active
  • Are better educated
  • Have an extended social network including both friends and family
  • Usually were satisfied with their lives before they retired
• Older adults who have difficulty adjusting to retirement

  • Have inadequate income
  • Have poor health
  • Must adjust to other stress that occurs at the same time as retirement, such as the death of a spouse
• Depression in older adults is not more common and is not more often caused by psychological factors
• Depression in older adults is more likely to be chronic which is likely linked to higher rates of medical problems in older adults
• Predictors of depression in older adults

  • Earlier depressive symptoms
  • Poor health
  • Disability
  • Losses such as the death of a spouse
  • Low social support
  • Social isolation
• Dementia


  A global term for any neurological disorder in which the primary symptoms involve a deterioration of mental functioning