I wish I was making up this stuff but in fact all I am doing is posting the link.
I think people with Neanderthal genetics grieve much longer and take a greater deal of time to absorb emotional insults of all kinds. It is because he/she is a small tribe animal designed for lifelong bonds, sincere attachments and genuine friendships. Emotional scars are likely to be deeper and never heal over as they do in Homo Sapiens. I think this is intimately tied in with survival in cold weather climates and smaller social groups that must be absolutely devoted to one another in order to persevere. Homo Sapiens might get over the death of a loved one in two weeks but I believe Neanderthals would definitely define a time period like that as symptomatic of some kind of mental illness for certain. If they knew a woman had lost a child to a predator or to a crack in the ice sheet and she was breakdancing and flirting two weeks later they would assume she had lost her mind.
As with everything, slower, deeper, more meaningful and longer lasting. Everything was like this with the Neanderthals. Bonds with other people were not transient affairs and there was no such thing as a disposable friendship.
I am convinced this is the exact reason that people with "Aspergers" have such a deep conviction that their own kind are "coming back to get them" for the first thirty years of their lives. They knew the Neanderthals never leave a man or woman behind, ever. If somebody was lost, they didn't move on. They camped right there, for years if necessary and searched under every pebble in a hundred mile radius until they found that missing tribal member / child / elder. They would persist in this effort until every soul was accounted for, either dead or alive. Nobody was ever willingly abandoned or regarded as a necessary casualty. To the Neanderthal everybody in the tribe was of the same worth and anybody who got lost could count on all their fellows searching for them ceaselessly until they were recovered or it was known what had happened to them.
In contrast, a tribe with several thousand people in it likely wrote off disappearances on a weekly basis. Homo Sapiens probably had the attitude easy-come, easy-go. "Where's Biff? We are moving camp in the morning. If he doesn't show up, that's his loss. We can't sacrifice our schedule for one meaningless life." Pretty transient connections to each other that were forever changing in real-time. "My kid vanished last week. He probably fell into a ravine somewhere. Ah, I can always make more. I just dumped my wife for a new young girl I've had my eye on, she is plenty fertile."