Evolutionary models of food sharing
Evolutionary biologists have developed various theoretical models to explain the evolution of food-sharing behavior—"[d]efined as the unresisted transfer of food" from one food-motivated individual to another[1]—among humans[2][3][4][5] and other animals.
Researchers have developed several types of food-sharing models, involving phenomena such as kin selection, reciprocal altruism, tolerated theft, group cooperation, and costly signaling.
In other words, kin selection implies that food will be given when there is a great benefit to the recipient with low cost to the donor.
When Hamilton's rule is applied to food-sharing behavior, a simple expectation of the model is that close kin should receive food shares either more frequently or in larger quantities than distant relatives and non-kin.
[14][2][16] Like the kin selection model, food will be shared when the benefit towards the recipient is greater than the costs to the donor, such as a period of surplus.
In 1984, Jim Moore[17] proposed a model for the evolution of reciprocal food-sharing based on evidence from chimpanzees and modern human hunter-gatherer groups.
If other group members witnessed this change in dominance position, then the beggar may demonstrate redirected aggression and attack a lower-rank bystander.
Thus, Moore's model predicted that natural selection would favor aggressive sharing and assertive reciprocation to re-establish status.
[22] This developed in response to variance-reduction models, as reciprocal behavior might have socially related taboos tied to it (such as rules preventing a person to accumulate more wealth).
Variance-reduction models seek to explain why redistribution of large food packages (caches or prey items) occurs in daily practices of hunter-gatherers.
When food packages are small to begin with, then theft is less tolerated as portions have lower returns along the assumed diminishing value curve.
salmon run or agricultural harvest), or when accumulated food no longer follows a diminishing curve (as with financial capital).
Among the Meriam, a family will sponsor a turtle-hunting group to collect turtles for feasting purposes associated with funerary activities.
Since the hunting group does not receive any of the turtles in return, this behavior does not fit within a reciprocal or cooperative food-sharing framework.
The leaders of these hunting groups signal their skills, specialized knowledge, and charisma which allow them to gain widespread social status when they are successful.
The family who sponsored these hunting groups receives all of the captured turtles with no expectation of reciprocal payment in the future.
[32] From this perspective, food-sharing is a form of trade-based reciprocal altruism where privately owned food is used to reward labor.
Bruce Winterhalder[16] incorporates food-sharing among groups into the diet breadth model derived from optimal foraging theory as a means to reduce risk.
Through a series of simulations exploring values of group size and other parameters of the model, the results suggest that risk is effectively reduced by pooling and dividing equal shares of resources.
