We all see things differently GGM2 and your definition of low IQ ( post before last one) would seem to apply to Corbyn ( confidently over estimating himself on the Marr Show this morning.)
The man is deluded, because he moves in such limited circles ( his Momentum cabal) he really imagines that most voters think like him, ....wrong!
Don't be silly Roses, it isn't me that looked at this phenomena but psychologists. I cannot define anyone's IQ and neither can you without access to their tests and these have been set up by long research again by psychologists, to do that.
I was just commenting on one possible explanation why people might believe what are actually only their opinions must be right, but it is only one idea and, of course, it may have nothing to do with such entrenched views.
I did not see such "my opinion so it must be right" views from Corbyn in this morning's in the Marr Show interview and I would be hard pushed to describe him as appearing over confident either, but, of course, that may say more about your view of life and mine rather than Corbyn's IQ.