Does calling users ignorant really increase readership?

It is quite common to see websites advertising lists like "The 10 most amazing ___ you never heard of!"

enter image description here

What is common among them, besides the sensationalism, is that they all claim that the readers are ignorant, or outright stupid (especially if the list is about things average educated people should know about)

It's obvious that the titles are formulated this way for clickbait, but does it really increase readership, to put such phrases at the end of every article?

  • ... you never heard of
  • ... you had no idea about
  • ... they don't want you to know
  • ... you never learned
  • ... nobody talks about
  • ... bigger / newer / older than you realize
  • ... you believe in but they just made up

It should be easy to test: you could randomly present visitors a title with such a phrase half the time, and without it the other half, then compare clicks. Were such studies done?

Note: I'm not interested in using such a scheme, I'm just curious whether there is any research behind it.