As a guess, I would suspect that the researchers who set up the experiment are more careful about their analysis than NPR is with its reporting. NPR needs to popularize its information, thus ensuring that we, the casual reader, can get a grasp of what's going on. That necessarily dumbs down the content.
Why did they go half way, though? If you're going to dumb down things, why don't just say "scientists found that" instead of giving a distorted view of the experiment, popularizing a wrong idea of what real science actually looks like?
