Evidence for a midlife crisis in great apes consistent with the U-shape in human well-being.
Level 5 - mechanism / opinion, no new human data
Animal research studying subjective well-being across the lifespan in non-human primates.
PubMed 23169637 · doi:10.1073/pnas.1212592109
What was done
Researchers evaluated the lifespan trajectory of well-being in 508 great apes across three distinct cohorts (two samples of chimpanzees and one sample of orangutans). Individual ape well-being was assessed using standardized reports completed by human raters familiar with each animal. The relationship between age and well-being was analyzed using both parametric and non-parametric statistical methods.
What was found
The abstract reports no exact numerical values, effect sizes, or confidence intervals. It reports that well-being in chimpanzees and orangutans followed a U-shaped curve across age—starting higher in youth, reaching a minimum in midlife, and rising again in older age—consistent with patterns documented in human populations.
Why it matters
These findings suggest that the midlife nadir in well-being observed in humans is not solely driven by modern human socioeconomic institutions, culture, or societal structures, but may have evolutionary and biological underpinnings shared with other great apes.
Limits
The study relies on proxy assessments of ape well-being scored by human observers rather than direct internal subjective reports. The abstract does not provide exact point estimates, inflection ages, or effect sizes. Generalizability to human psychological phenomena remains an indirect evolutionary parallel rather than direct human evidence.
Cited by
- supports Happiness across the lifespan follows a curvilinear pattern where midlife has some of the lowest levels of happiness and life satisfaction.