Following is from an article in The New Yorker titled, "The Decline Effect and The Scientific Method":
The decline effect is troubling because it reminds us how difficult it is to prove anything. We like to pretend that our experiments define the truth for us. But that’s often not the case. Just because an idea is true doesn’t mean it can be proved. And just because an idea can be proved doesn’t mean it’s true. When the experiments are done, we still have to choose what to believe.Confirmation bias is difficult to assess. Add the "publish or perish" environment in research and you have an environment where even honest scientists can publish incorrect work.
Scientists can get upset when presenting their results because others start picking apart their data. But it is one of the best things that can occur, as another perspective can cause them to see the the truth about their research.