Abuelas, Nanas, Grandmothers

It seems that grandmothers have become popular again, credited with promoting the fitness of their descendants. I don't disagree with that premise. I do disagree with several points.

1.  If the children, when they get old, replicate the cultural/behavioral  strategies of the grandmother, then it becomes an ancestral strategy. I am sure that evolutionary biologists look at it generation by generation, but if  you look at it in terms of everyone the grandmother influences, it seems clear that her influence is copied across generations and at any point in time she is, what the Mongolians would say, the one who founds a lineage, perhaps even a lineage going back as far as Genghis Khan. However, no matter how often I repeat myself, my words fall on deaf ears. We cannot escape from kin selection/inclusive fitness. I have to wonder if it is the sole means of explaining cooperation (other than reciprocal altruism - which has tough requirement and thus is tough to test) even in other species. However, I leave that for future generations to solve.

2.  I also agree that when a mother has more than one child she needs  a strategy to get them to cooperate with her and with one another.  Part of that strategy may involve having the grandmother teach them those skills while the mother tends to breast feeding, foraging, preparing food, keeping her husband happy - all cultural practices that she had been taught by her mother and grandmother. That teaching may have been explicit - "Do this!", or it may have been implicit, perhaps described in a story, or it may have been taught by modeling behavior. The how is less important than the result. 

3. The grandmother did more than teach her daughter (as a child) to find nutritious roots. That was only one thing she might have done, but even that she learned from her mother, who learned it from her mother. To try to make this clear, girls learn certain skills by watching their mothers. They learn other skills - probably social skills - from their grandmothers.