• Intelligence: the global capacity of the individual to act purposefully, think rationally, and deal effectively with his environment (Wechsler, 1939). • g: general intellectual capacity.
Intelligence Age Changes in Overall Intelligence • Cross-sectional studies: gradual decline in IQ from age 30. • Longitudinal data: maintenance of overall IQ age 60, after which there is a decline. Age Changes in Components of Intelligence • Crystallized intelligence: rises or shows stability into the 70s. • Fluid intelligence: begins to decline earlier.
Short-term memory: information held for 30 seconds. • Primary memory information is passively stored for immediate recall. • Shows only small age-related declines. • Working memory actively performing mental operations on information. • Shows substantial declines with age.
Long-term memory: encoded information is stored and can remain for years. • Semantic memory: stored facts. • Relatively stable with the exception of word-finding errors. • Episodic memory: ability to recall events. • Shows declines that can be improved with environmental support.
Procedural memory: skill learning and retention. • Implicit memory processes: well-learned, automatic mental processes. • Explicit memory: conscious, effortful process of recalling details of events. • Generally, there is little change in procedural memory over time.
Health • Poor health can affect cognition. • Declines in vision and hearing are related to declines in IQ scores. • Common cause hypothesis • Chronic diseases • Terminal decline • Medication
Genetics • Cognitive abilities are among the most heritable of behavioral traits. • Genetics explain 60 percent of individual differences in general cognitive ability.
Demographics and Sociobiographical History • Women have slight advantage over men in episodic memory, verbal tasks, and maintaining brain weight. •Sociobiological history (level of professional prestige, social position, and income). • Rate of cognitive decline the same regardless sociobiological history.
Intellectual Activity • Adults who read books, take classes, travel, etc. seem to fare better intellectually over time particularly in terms of crystallized intelligence.
Physical Exercise • Causal link between physical exercise and intellectual skill. • Exercise helps maintain cardiovascular fitness, which is linked to mental maintenance.
Subjective Evaluation of Decline • Strong relationship between age and subjective reports of cognitive decline. • However, there is not a relationship between subjective report and actual decline.
