In the early history of science fiction, and indeed fiction as a whole since Mary Shelley’s Frankenstein, there has been a fascination with humans who have been taken over by sinister forces. In one very early TV science fiction program the small American town was taken over by aliens (yet again: why don’t aliens take over towns in other countries?) who did their dastardly alien tricks on upstanding citizens, operating on them and then releasing them to carry out alien orders.
How to distinguish these interstellar traitors from fine, upstanding, 100% Americans? Even as a child I could see the answer: there were clear drill marks on the back of the necks of the zombies, where something had been implanted: Communism, most probably. However, in this drama, possibly because the drill marks were generally obscured by clothing, another test was applied by the besieged townfolk: the aliens implanted into the bodies of Americans were unable to properly flex their little fingers. Ask them to flex their pinky finger, and democracy is saved.
I have not been particularly interested in fingers. I concede that they are useful, and that to be without them would be a human tragedy, but even in my gratitude I have not accorded them high status.
Now young Woodley strides onto the scene, to remind me that much of great import may be derived from the study of finger length ratios. Looking at your hands, palm downwards, you will note that when you compare your index finger (number 2, where your thumb is number 1) with your ring finger (number 4) you will find that….. that finger 4 is visibly longer than finger 2. Or perhaps not. The ratio of finger lengths may be a sensitive measure of pre-natal androgen, or a random variation which should not concern us very much, unless we are intrinsically interested in fingers.
We measured the 2D:4D digit ratios (collected from both hands) and a personality trait known as dominance (measured with the Directiveness scale) in a sample of women attending a feminist conference. The sample exhibited significantly more masculine 2D:4D and higher dominance ratings than comparison samples representative of women in general, and these variables were furthermore positively correlated for both hands. The feminist paradox might thus to some extent be explained by biological differences between women in general and the activist women who formulate the feminist agenda.
They got 25 women at a feminist conference to have both hands scanned (so that finger length ratios could be calculated) and then 24 of them filled in a “Directiveness” questionnaire, which seems to measure dominance and a tendency towards bossiness.
In summary, the feminist activist sample had a significantly smaller (i.e., masculinized) 2D:4D ratio than the general female samples. The size of this difference corresponds approximately to a 30% difference in prenatal testosterone/estradiol ratio, which was the index found to have the strongest association with 2D:4D (Lutchmaya et al., 2004). Directiveness self-ratings also exhibit a large and highly significant difference in the predicted direction. It is notable that the feminist activist sample 2D:4D was also more masculinized than those of the male comparison samples, except for the left hand in the aggregate sample (see Table 2).
This is a small sample, though a big number of feminist activists, given their rarity in the population, and the association with dominance is intriguing.
So what, and what does this have to do with intelligence? Nothing directly. However, there have been claims that the 2d:4d ratio is weakly correlated with intelligence (in another small sample of people).
Marc F. Luxen and Bram P. Buunk. Second-to-fourth digit ratio related to Verbal and Numerical Intelligence and the Big Five. Personality and Individual Differences 39 (2005) 959–966
There may be something in this finger business. It would be worth checking on a much larger representative sample which has already been tested for intelligence or scholastic ability, and ideally on which genomic data is available.