That's a roughly high-school-level misunderstanding of what the Prisoner's Dilemma means, though I suppose it makes sense to be surprised that humans care about each other if you'd never met a human, and it did make sense to be confused by why humans care about each other until we recognized that (uncertainly) iterated dilemmas and kin selection were involved. I believe a great many people on LessWrong also reject the economic consensus on this issue, however; they think that two rational agents can cooperate in something like a classical PD, provided only that they have information about one another's (super)rationality. See True Prisoner's Dilemma and Decision Theory FAQ.
In the real world, most human interactions are not Prisoner's Dilemmas, because in most cases people prefer something that sounds like '(Cooperate, Cooperate)' to '(Cooperate, Defect)'. whereas in the PD the latter must have a higher payoff.
This is what was said:
"It (game theory) assumes actors are more rational than they often are in reality. Even Nash faced this problem when some economists found that real subjects responded differently from Nash's prediction: they followed rules of fairness, not cold, personal calculation (Nassar 1998: 199)"
Yeah, I remember reading that some slightly generous version of tit-for-tat is the most useful tactic in prisoner's dilemma at least if you're playing several rounds.
xkcd's Up-Goer Five comic gave technical specifications for the Saturn V rocket using only the 1,000 most common words in the English language.
This seemed to me and Briénne to be a really fun exercise, both for tabooing one's words and for communicating difficult concepts to laypeople. So why not make a game out of it? Pick any tough, important, or interesting argument or idea, and use this text editor to try to describe what you have in mind with extremely common words only.
This is challenging, so if you almost succeed and want to share your results, you can mark words where you had to cheat in *italics*. Bonus points if your explanation is actually useful for gaining a deeper understanding of the idea, or for teaching it, in the spirit of Gödel's Second Incompleteness Theorem Explained in Words of One Syllable.
As an example, here's my attempt to capture the five theses using only top-thousand words:
If you make a really strong computer and it is not very nice, you will not go to space today.
Other ideas to start with: agent, akrasia, Bayes' theorem, Bayesianism, CFAR, cognitive bias, consequentialism, deontology, effective altruism, Everett-style ('Many Worlds') interpretations of quantum mechanics, entropy, evolution, the Great Reductionist Thesis, halting problem, humanism, law of nature, LessWrong, logic, mathematics, the measurement problem, MIRI, Newcomb's problem, Newton's laws of motion, optimization, Pascal's wager, philosophy, preference, proof, rationality, religion, science, Shannon information, signaling, the simulation argument, singularity, sociopathy, the supernatural, superposition, time, timeless decision theory, transfinite numbers, Turing machine, utilitarianism, validity and soundness, virtue ethics, VNM-utility