I think there’s also a trend for academics to date other academics. How come those random forests didn’t detect it?
Likely because all of the people in question were academics, or at least undergraduate ones, so there was no chance to detect differences in how they matched with non-academics:
Sample A consisted of 163 undergraduate students (81 women and 82 men; mean age = 19.6 years, SD = 1.0) who attended one of seven speed-dating events in 2005. Sample B consisted of 187 undergraduate students (93 women and 94 men; mean age = 19.6 years, SD = 1.2) who attended one of eight such events in 2007. Sample size was determined by the number of speed-dating events we were able to hold in 2005 and 2007 and the number of participants we were able to recruit for each event while maintaining an equal gender ratio. All participants, who were recruited via on-campus flyers and e-mails to participate in a speed-dating study, had the goal of meeting and potentially matching with opposite-sex participants. [...]
The present results were obtained with undergraduate samples; a more demographically diverse sample might exhibit matching by sociological factors such as age, socioeconomic status, cultural background, or religious background.
Likely because all of the people in question were academics, or at least undergraduate ones, so there was no chance to detect differences in how they matched with non-academics: