Some folks writing in Frontiers in Behavioral Neuroscience claim to have found a body chemistry reason for feeling of contentment later in life.  I’m a little skeptical, but have a read.  Excerpt:

Helping behaviors and life satisfaction generally increase after middle-age. Identifying the neural substrates of prosocial behaviors in older adults may offer additional insights into these changes over the lifespan. The present study examines the endogenous release of the neuromodulator oxytocin (OT) in participants aged 18–99 and its relationship to prosocial behaviors. OT has been shown to influence trust, altruism, charity, and generosity, yet the effect of age on OT release has not been well-established. Blood samples before and after a video stimulus were obtained from 103 participants in order to examine the impact of OT on prosocial behaviors. We found that OT release following a social prime increased with age (r = 0.49, p = 0.001) and that OT moderated the relationship between age and donations to charity. We tested for robustness by examining three additional prosocial behaviors, money and goods donated to charity during the past year and social-sector volunteering. OT moderated the impact of age on all three prosocial behaviors (ps < 0.05). The analysis also showed that participants’ change in OT was positively associated with satisfaction with life (p = 0.04), empathic concern (p = 0.015), dispositional gratitude (p = 0.019), and religious commitment (p = 0.001). Our findings indicate that the neural chemistry that helps sustain social relationships and live a fulfilled life appear to strengthen with age.

Here’s the summary:

Our analysis has identified a likely neurochemical impetus for prosocial behavior that remains intact with age. The data showed that older participants experienced the largest change in OT in response to an emotional stimulus compared to other age groups. The correlation between neurochemical changes and four measures of prosocial actions suggest that OT impacts prosocial behaviors more strongly in aging adults for small increases in OT. As in previous research, our data show that individuals who dispositionally have high empathic concern have a larger increase in OT after a video prime with social content (Barraza and Zak, 2013; Zak and Barraza, 2013). This dispositional effect partially dampens the age effect on OT from the prime revealing a trait-state interaction that influences the acute donation decision. The “high oxytocin responder” effect has been found for other stimuli and behaviors (Rameson et al., 2012; Procyshyn et al., 2020) and has been previously reported for the video used here (Barraza and Zak, 2009). Nevertheless, the positive age gradient for age on donations was maintained for both low and high ΔOT responders. Note that while there was no average change in OT for the video as in a previous study using the same stimulus (Barraza and Zak, 2009), in most published research using social stimuli to induce OT release, including studies with very large sample sizes, only about 50% of participants will show an increase (Barraza and Zak, 2013; Terris et al., 2018).

Yeah, that’s kind of thick.  And yeah, there’s some tentative language there, but that’s how science is actually supposed to work – it’s tentative, subject to new data.

I can’t talk for people in general, of course.  But I suspect that, even if there’s something to this, that there are much larger and more important factors.  Like me, plenty of folks I know, including my siblings, take a lot of joy in their families.  One of the greater things about growing older is seeing your kids launch, start their own lives, start their own families.  And grand-parenting is just fantastic.  Being a grandparent, after all, is the revenge we get for having been parents.

Us folks who are contemplating those golden years can look back on a lot.  Folks who have led a productive, thoughtful, well-considered life can look back on decades of personal and professional achievement, and that certainly leads to satisfaction.

What I’d like to see studied is this:  Compare these factors named here for measuring life satisfaction, but break out the study groups to analyze them in terms of professional and personal success.  Compare, say, a guy who started as a carpenter and ended up running a successful contracting company, to a guy who languished on odd jobs and welfare through his life.  Compare a woman who started as a switchboard operator and ended up as a regional vice-president of the company (my sister did precisely this) to a woman who gamed the welfare system by downloading six kids she couldn’t afford.

I expect you’ll find some correlations there, too.  Granted this doesn’t necessarily show causation – people who are focused, who work, who learn, who strive, are likely to be more successful and more pleased with their lives at any age, while the purposeless… are purposeless.

Still – that’s a study I’d read with some interest.