[Update: Steve Williamson says in comments the lack of communication started much earlier. If that's right, then I think my theory fails empirically in this case.]
If you are in a position of power and responsibility you need advisers. The main job of your advisers is to stop you saying something stupid in public. You say it to your advisers first, in private. If it's stupid, your advisors should tell you it's stupid. That's their job. If they fail to tell you it's stupid, and you say it in public, and the public tells you it's stupid, and you realise the public is right, you should fire your advisers. They have failed to do their job.
Update: you don't fire your advisers because they disagree with you; you fire your advisers because they didn't disagree with you when they should have disagreed with you.
In August 2010, the President of the Minneapolis Fed said something stupid in public.
In May 2013 he again said something stupid in public.
There may be other examples I don't know about.
That's OK. Even very intelligent people sometimes say stupid things. But it's the job of their advisers to stop them saying stupid things in public. And in these two cases, any halfway competent macroeconomist could have advised him that he was about to say something stupid in public. By saying something like this, and this, like I did, only in private.
Noah Smith thinks that [update: Noah in fact says we can't tell whether] Narayana Kocherlakota fired his advisers because he has seen the saltwater light and his advisers are freshwater. Maybe that's part of it. But it's good to have some advisers who see things differently from you, because they might see things you would miss. Provided they do their job.
I think it's much more mundane than that. I think he fired his advisers because he realised they had failed to do their job.
If you model the central bank as setting a nominal rate of interest, then if the natural rate of interest falls, and the central bank does not change the nominal interest rate in response, then there will be excess supply of labour and goods if nominal wages or prices and their inflation rates are sticky. The inflation rate would need to rise to reduce the real interest rate to restore equilibrium. But the inflation rate would actually fall, if there is excess supply of labour and goods. This is a problem with central banks setting nominal interest rates and not responding to shocks. Wicksell knew about this problem. Any halfway competent macroeconomist knows about this problem. If his advisers had been halfway competent macroeconomists, they would have told him about this problem. If they failed to do that, they should have been fired.
This is like a bus driver saying you need to turn the steering wheel clockwise to turn left, and his advisers not pointing out the problem.
In May 2013, he wrote: "I thank participants in a FRB-Minneapolis bag lunch for comments." Unless those comments included something similar to what I have said above, they were useless.