Overview
- A peer-reviewed paper in the journal Intelligence introduces a composite Cognitive‑Personality Functioning Index built from nine markers tied to life success.
- Two modeling approaches applied to lifespan data both indicated the highest overall functioning in late midlife, roughly ages 55–60.
- Fluid abilities such as reasoning, processing speed, and memory span tend to crest in early adulthood before declining, whereas crystallised intelligence strengthens for decades.
- Traits including conscientiousness, emotional stability, moral reasoning, financial literacy, and resistance to sunk‑cost bias reach later highs, supporting effective decision‑making.
- The authors propose that high‑stakes roles typically suit candidates about 40–65, while stressing that population averages do not dictate individual trajectories.