It's been my very
unscientific observation that :
Left-leaning men tend to be less overtly masculine. Less interested in sports, competition, less handy with tools, fixing cars and so forth. All the things we tend to think of as manly. They are less aggressive and less likely to demonstrate anger or show any willingness to thump your ass should you do anything to threaten them. They are more likely to insult rather than swing a fist. I can USUALLY guess within a few minutes of meeting a MALE whether or not he's left-leaning or right-leaning. But - I have been wrong about this occasionally.
Moderates are harder to guess. Sometimes I think moderates are either unwilling to discuss their opinions if they're not well received, or maybe they seriously just don't care. One moderate friend of mine is supremely calm about issues, believing that God will work it out; the other seriously, profoundly doesn't care at all, saying that in the final analysis, there's not a lot of difference on either side.
Left-leaning women - again, MY observation, not based on anything scientific - tend to be less feminine, and less attractive. This is a generality - I have very left-leaning relatives who are super model gorgeous. Among my right-leaning and left-leaning female relatives - the right-leaning ones look better, seem happier, their intelligence leans toward the practical, pragmatic - they're what their friends would call - "wise".
Even after reading the references, I'm still not sure this was ever written in earnest. None of the "science" accounts for why people change their minds on issues.