Is there a more common term for that? I think it's a huge problem in polling. I googled and I didn't make much progress. I found this...
There is considerable debate about whether survey respondents regularly engage in "expressive responding" – professing to believe something that they do not sincerely believe to show support for their in-group or hostility to an out-group.
The problem is that "expressive responding" is a technical term. At Wikipedia I searched for "expressive responding" (in double quotes) and I got zero results.
Of course that mental mindset is big deal when it comes to Trump. A recent example - Lots of Republicans suddenly think the economy wasn't that bad after all. There's not exactly a "debate" when it comes to Trump and republican voters. They always do it when Trump is involved. It's not a coincidence that the election always causes a rapid change in what they say they believe.
I'll go with that. It seems really good and it's far better than any polling term like "expressive responding" because that stuff reeks of polling guru dork jargon speak. It's crazy to me how American politics tends to be devoid of basic concepts like in-group signalling, margin of error, etc. Polling is considered some kind of augury producing magic numbers that can divine the future.
I wonder how much time I'd have to spend at the 538 website to find their explanation of in-group signalling and I wonder what ridiculous term they use instead.