Can iq change in adults
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Can IQ Change in Adults?
Age-Related Cognitive Decline and IQ Stability
Research indicates that while IQ scores can remain relatively stable throughout adulthood, there are age-related changes in specific cognitive abilities. Studies using the Wechsler Adult Intelligence Scales-Fourth Edition (WAIS-IV) have shown that Full-Scale IQ (FSIQ) and composite scores such as Verbal Comprehension, Perceptual Reasoning, Working Memory, and Processing Speed exhibit normal cognitive developments and declines across the adult lifespan. This suggests that while the overall IQ may not change drastically, the components that make up the IQ score can vary with age.
Longitudinal Studies on IQ Stability
Longitudinal studies have provided insights into the stability of IQ from childhood to adulthood. For instance, the Munich Longitudinal Study on the Ontogenesis of Individual Competencies (LOGIC) found that general intelligence remains moderately stable from preschool to early adulthood, with higher stability observed in individuals with initially lower IQ scores. Similarly, another study demonstrated that IQ scores measured in infancy can predict adult IQ and academic achievement, indicating a continuity of intelligence from early life to adulthood.
Impact of Brain Structure on IQ
Changes in brain structure, particularly cortical thickness and surface area, have been linked to variations in IQ. Research has shown that more intelligent children tend to have a thinner cortex at age 10, which thins faster over time, but by age 42, a thicker cortex is associated with higher intelligence. Additionally, reductions in cortical surface area in specific brain regions have been correlated with lower IQ scores in young adults born with very-low-birth-weight (VLBW).
Cognitive Decline in Older Adults
In older adults, studies have shown that while there is a significant decline in brain volumes such as grey matter and white matter, these changes do not necessarily correlate with a decline in IQ. For example, a longitudinal study of healthy older adults found that despite neuroanatomical decline over four years, verbal and non-verbal IQ measures remained stable. This suggests that cognitive decline in older adults may not always be reflected in IQ scores.
Influence of Health and Socioeconomic Factors
Health conditions and socioeconomic factors can also influence IQ changes in adults. Studies have found that higher IQ scores in early life are associated with lower mortality rates in middle to late adulthood, suggesting that cognitive function can be affected by overall health and lifestyle. Additionally, socioeconomic position in adulthood can mediate the relationship between early-life IQ and later-life outcomes, although this is not a universal finding.
IQ in Adults with Autism
For adults with autism, childhood IQ has been a reliable predictor of cognitive functioning in later life. Most individuals with an average IQ in childhood maintain stable cognitive abilities into mid-to-late adulthood. However, a significant minority may experience severe behavioral disturbances and cognitive decline, often associated with other health issues such as epilepsy.
Conclusion
In summary, while IQ scores in adults tend to remain relatively stable, various factors such as age-related cognitive changes, brain structure, health conditions, and socioeconomic status can influence specific cognitive abilities and overall cognitive function. Longitudinal studies and neuroimaging research provide valuable insights into how these factors interact over the lifespan, highlighting the complexity of cognitive development and decline in adulthood.
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