"Newcomblike decision problems" are scenarios in which your choice correlates with the outcome by some pathway other than the direct physical consequences of your act--for example, because somebody else is predicting you; or you're interacting with someone very similar to yourself; or people with different genes behave differently. Newcomblike problems force splits between different decision theories that would give the same answer in more "normal" problems. Perhaps the most realistic Newcomblike problem is voting in elections, where a large population of voters probably contains at least some people similar to you. The class of scenarios as a whole is named after the (less realistic) Newcomb's Problem.