If a judge learned about a case from any other source he would recuse himself. In Europe, on the other hand, the judge is an investigator. He has a staff of researchers and prosecutors, and learns as much as he can from his own resources. Our reliance on the court evaluator is one example. It is easy to think of others.
Criminal judges receive pre-sentence investigations.
In Family Court, and increasingly in Supreme Court, we as judges turn to social investigations and psychological evaluations commissioned by the court or by a law guardian. And in commercial matters and tort cases decisions are increasingly based on findings outside of the courtroom. One reason is the complexity and difficulty of the facts we must weigh. Science has enhanced our ability to trace cause and effect, but the reasoning that takes us from an instance of negligence to an injury gets harder to follow. It should come as no surprise that many courts have come under criticism for results that lack a solid scientific basis.