Signalling is the conveyance of information outside of the direct in-band communication channel.
Example: Candidate at an interview for JPL went to Harvard.
This signals that they may have some grit, connections, a good demeanor and interesting traits.
Of course, this signal could be misleading, but this isn’t meant to conclude the investigation of what the signal implies. It’s just an early step in the process.
Now the cooler the signalling attribute, the stronger the signal, right?
Take a look at this panel from the manga “Cromartie High-School”:
This is a signal-paradox.
If you lack an expected signal in a context, then you may actually signal higher on the implied attributes than if you had actually displayed the signal at all.
Example: Candidate at an interview for JPL never went to university at all.
How the heck did they manage to get put in front the interviewer then?
What incredible thing did they do to manage that?