alt Hacker NewsThank you, I came here to say so much in less eloquent terms.
It's not surprising to find clustered sentiment from a slice of statistically correlated language. I wouldn't call this a "personality" any more than I would say the front grill of a car has a "face".
Deterministically isolating these clusters however, could prove to be an incredibly useful technique for both using and evaluating language models.
It's not even really the researchers' fault, academic psychological personality research is in general philosophically very weak / poor, in that they also almost always conflate "models of / talking about personality" with actual personality, and rarely actually check if things like the MBTI or Five-Factor Model actually correlate meaningfully with real behaviours.
Those that do find correlations between self-reported personality and actual behaviours tend to find those to be in a range of something like 0.0 to 0.3 or so, maybe 0.4 if you are really lucky. Which means "personality" measured this way is explaining something like 16% of the variance in behaviour, at max.