Rising verbal intelligence scores: implications for research and clinical practice

Area of Science:

• Psychology
• Cognitive Science
• Psychometrics

Background:

• Intelligence test scores have shown a general upward trend over decades.
• The Wechsler Adult Intelligence Scale (WAIS) is a widely used measure of adult intelligence.
• The specific trend of WAIS Vocabulary subtest scores requires investigation.

Purpose of the Study:

• To determine if scores on the Wechsler Adult Intelligence Scale (WAIS) Vocabulary subtest have increased over time.
• To quantify the rate of change in WAIS Vocabulary scores for different adult age groups.

Main Methods:

• A systematic search of major psychology journals was conducted.
• Data from studies involving healthy younger and older adult participants reporting WAIS Vocabulary scores were collected.
• A meta-analysis was performed on the collected WAIS Vocabulary scores.

Main Results:

• WAIS Vocabulary scores have demonstrated a significant upward trend.
• Younger adults showed an increase of 0.117 points per year (1.52 IQ points/decade).
• Older adults exhibited a higher rate of increase, 0.367 points per year (4.79 IQ points/decade).

Conclusions:

• The Wechsler Adult Intelligence Scale (WAIS) Vocabulary subtest scores are rising, mirroring trends in other intelligence measures.
• This suggests an increase in verbal intelligence, particularly notable in older adult populations.
• The findings have implications for understanding cognitive changes and test norming over time.