Overview
- The peer‑reviewed study, led by Gilles Gignac of the University of Western Australia and published in Intelligence, integrates data across 16 cognitive, personality and judgment dimensions.
- Across the composite, many people reach their highest overall functioning between roughly ages 55 and 60, with noticeable decline typically not appearing until the mid‑70s.
- Specific traits peak later than raw processing speed, with conscientiousness averaging its high point around 65 and emotional stability around the mid‑70s.
- Moral judgment, resistance to cognitive biases and crystallized knowledge continue improving into the 70s and even 80s, counterbalancing earlier drops in processing speed.
- Using data from more than 5,000 adults aged 19 to 88 across multiple countries, the authors link the pattern to real‑world decisions, suggesting a leadership sweet spot roughly from 40 to 65 and urging employers to judge by ability rather than age.