Jamie Doward “Black humour is sign of high intelligence, study suggests” https://www.theguardian.com/science/2017/jan/29/dark-humour-high-intelligence-study
The British Psychological Society Research Digest blog*3 reports that the study found three groups of participants. The group with the highest sick humour appreciation and comprehension scored the highest in verbal and non-verbal IQ tests, were better educated, and scored lower for aggression and bad mood.
A second group showed moderate comprehension of the jokes but enjoyed them the least. These were people with average intelligence scores, but had the highest negative mood and the highest aggression levels.
The third group showed moderate sick humour comprehension and preference, had average intelligence scores, but were generally of a positive mood and had moderate aggression scores.
*2:Ulrike Willinger, Andreas Hergovich, Michaela Schmoeger, Matthias Deckert, Susanne Stoettner, Iris Bunda, Andrea Witting, Melanie Seidler, Reinhilde Moser, Stefanie Kacena, David Jaeckle, Benjamin Loader, Christian Mueller & Eduard Auff “Cognitive and emotional demands of black humour processing: the role of intelligence, aggressiveness and mood” http://link.springer.com/article/10.1007/s10339-016-0789-y
*3:Christian Jarrett “If you like sick jokes, maybe it’s because you’re just so smart” https://digest.bps.org.uk/2017/01/18/if-you-like-sick-jokes-maybe-its-because-youre-just-so-smart/
*5:Mentioned in http://d.hatena.ne.jp/sumita-m/20090227/1235705016