Neurobiological foundations for Socionics/Jungian types
What do you guys think of Dario Nardi and Helen Fisher's work? Nardi did studies using EEG (tracking/recording electrical activity in the brain) to find correlations between use of certain cognitive functions and activity in certain brain regions (summary here). Fisher noticed four main types related to the degree of expression of four hormones/neurotransmitters and posits a theory of attraction based on them (summary here). In broad strokes, it seems to me that serotonin = Si ego, dopamine = Se ego, testosterone = NT, estrogen = NF, though maybe some could be debated or maybe some individuals don't fit perfectly. E.g., an LII stuck in a tertiary loop (in MBTI parlance; basically means overusing Si and underusing Ne) might have more serotonin than testosterone.
Among my friends, I feel like Fisher's theory of attraction explains the relationships that Socionics doesn't explain (though they each explain roughly the same %). Out of my EII friends, I am the one who likes LSEs the most, and even then, I seem to be more attracted to Gamma NTs. I have two EII friends dating LIIs, an LSE dating an SEI, etc. I also have an EII friend dating an SLI, two ILIs dating each other, and SEI who dated an LII for a long time, so I don't think Socionics is wrong, but I think Fisher's theory can add to it.
(My post implicitly assumes that there is a one-to-one mapping between Sociotypes and MBTI types. I think it's as simple as keeping the top two cognitive functions the same. I.e., EII/INFj = FiNe = INFP.)