For Samuels and Stich: Everything.
Well actually, a lot of their papers repeat the same points. Perhaps as a result of publish or perish, least publishable units, and all that. If you want to read just one article to save time, go with "Ending the Rationality Wars."
For Pinker, I was mainly thinking of chapter 5 of his book How the Mind Works (an excellent book, I'm somewhat surprised few people around LW seem to have read it.) His discussion is based on lots and lots of other peoples' work. Cosmides and Tooby show up a lot, and double checking my copy so does Gigerenzer, though Pinker says nothing about Gigerenzer's "group approach" or anything like that. (Warning: Pinker shows frequentist sympathies regarding probability.)
Samuels et al.'s Ending the Rationality Wars is a good paper and I generally agree with it. Though Samuels et al. mostly show that the dispute between the two groups has been exaggerated, they do acknowledge that Gigerenzer's frequentism leads him to have different normative standards for rationality than what Stein (1996) called the "Standard Picture" in cognitive science. LessWrong follows the Standard Picture. Moreover, some of the criticisms of Gigerenzer & company given here still stand.
I skimmed chapter 5 of How the Mind Works but didn'...
I've spent so much time in the cogsci literature that I know the LW approach to rationality is basically the mainstream cogsci approach to rationality (plus some extra stuff about, e.g., language), but... do other people not know this? Do people one step removed from LessWrong — say, in the 'atheist' and 'skeptic' communities — not know this? If this is causing credibility problems in our broader community, it'd be relatively easy to show people that Less Wrong is not, in fact, a "fringe" approach to rationality.
For example, here's Oaksford & Chater in the second chapter to the (excellent) new Oxford Handbook of Thinking and Reasoning, the one on normative systems of rationality:
Is it meaningful to attempt to develop a general theory of rationality at all? We might tentatively suggest that it is a prima facie sign of irrationality to believe in alien abduction, or to will a sports team to win in order to increase their chance of victory. But these views or actions might be entirely rational, given suitably nonstandard background beliefs about other alien activity and the general efficacy of psychic powers. Irrationality may, though, be ascribed if there is a clash between a particular belief or behavior and such background assumptions. Thus, a thorough-going physicalist may, perhaps, be accused of irrationality if she simultaneously believes in psychic powers. A theory of rationality cannot, therefore, be viewed as clarifying either what people should believe or how people should act—but it can determine whether beliefs and behaviors are compatible. Similarly, a theory of rational choice cannot determine whether it is rational to smoke or to exercise daily; but it might clarify whether a particular choice is compatible with other beliefs and choices.
From this viewpoint, normative theories can be viewed as clarifying conditions of consistency… Logic can be viewed as studying the notion of consistency over beliefs. Probability… studies consistency over degrees of belief. Rational choice theory studies the consistency of beliefs and values with choices.
They go on to clarify that by probability they mean Bayesian probability theory, and by rational choice theory they mean Bayesian decision theory. You'll get the same account in the textbooks on the cogsci of rationality, e.g. Thinking and Deciding or Rational Choice in an Uncertain World.