Executive Functions across the Adult Life Span: Age-related Differences and Relationships with Intelligence

Abstract

The current thesis is aimed at exploring differences in executive functions (EFs) between healthy adults; additionally, the aim is to examine the relationship between EFs and intelligence through the comparison of younger and older adults. The Executive Functions Module of the Neuropsychological Assessment Battery (NAB), as a measure of EFs, and the Wechsler Adult Intelligence Scale a Fourth Edition (WAIS-IV), as a measure of intelligence, were implemented. Data of 485 NAB participants aged 18-99 were analyzed to examine age-related differences in EFs. Data of 126 NAB participants aged 18-88, who additionally completed the WAIS-IV, were used to investigate the relationship between EFs and intelligence. Decreases in the mean scores and increases in the dispersion of performance on the NAB Executive Functions Module subtests with advancing age were observed. Additionally, age-related relationships between the NAB Executive Functions Module and the WAIS-IV were demonstrated. Age-related differences with regard to the relationship between EFs and intelligence were associated with higher scores in older adults.