I wonder if it has to do with another part of aging as well, the losing of the fineness of eyesight and touch as well as slowed reactions would make the Elders less able to be effective in grooming another and the olders pull away because they know that they are less able to be effective. So the physical aspects degrade affecting the social ones. Is a possibility

Ms. Fischer hits the nail on the head with, "older monkeys might spend less time socializing because they find social interactions increasingly stressful and therefore avoid them."

As an older human female, not the spunky monkey I once was, I just don't have the energy to deal with drama or tolerance for people insinuating themselves into my personal business.

Maybe it's just me, but I swear I've picked up vibes from members of the opposite sex, relatives and strangers alike, who seem antagonistic for no discernible reason - at least not by me. (If you can't feed or breed you're of no use so need to be cut from the group?)
No way to counter something inexplicable, so for peace of mind just avoid it at all costs.

Furthermore, with age comes wisdom, if you're lucky, and the loss of some hormones of the love-is-blind variety, peels back the veil and brings the opportunists and users into sharp relief. Menopausal doom thoughts sure dampen desire to keep on giving 'til it hurts.

Sharp, taught, deeply insightful perceptions Steelwolf. Condolences Ms. Lineardyna. Truest truths I've seen in a long time I think, if we're right. Methinks the wisdom factor, possibly hormonally (partially) influenced, definitely experientially impacted, may untestabley, therefore
uncertainly be the primary factor in these issues in all living matter.

just hope taxypayers are not paying to study old monkeys! not much science apparently, just people getting money to play with monkeys. how about a cure for cancer, herpes, aids and all that? immortality is also possible. that stuff, i would pay for. psychology types need to stay in family counseling, and stop pretending to be scientists.

very insightful.