[Rickasaurus]

It seems to me if they modeled it as an infinite series of games instead of a single game they might find it's about denying your opponents resources for the next round. You also should consider things proportionally in terms of the resources of each group, one may be willing to take a bigger total loss that is smaller proportionally to disarm another group.

(I admit I only read through the abstract though)

[ohCh6zos]

That was my thought. If I thought my opponent could only survive a few turns I might be willing to take losses to prevent them from surviving more turns.

[nerdponx]

This is the same strategy as a company operating at a loss in order to put competitors out of business.

I think a lot of people will be tempted to say "that's obvious, you dummy!" but that's what good social science research does: it gives us a systematic explanation and principles of understanding for how people behave in groups.