T
Testosterone (”T”) appears to sharpen our focus and concentration on a single task, but it detracts from our ability to attend to several things at once. Although the average guy churns out 8 to 10 times as much testosterone as the average woman, female bodies appear to be much more sensitive to small amounts of the hormone. Because testosterone levels fall in men as they age, and rise in women in relation to dropping levels of the female hormone estrogen, the sexes become more alike as they age.
Men with high levels of T die younger, perhaps because they do more fighting and risk-taking and less consensus-building. T levels are lower among vegetarians, possibly because there are natural estrogens in the plants they eat.
On average, the high-T man is leaner, balder, more self-confident, more rambunctious, and less likely to have friendly smiles, and more likely to favor tattoos and gold jewelry than other men. Football players and construction workers are relatively high in T, whereas intellectuals and administrators are relatively low. Firefighters’ T rises on the way to a blaze and declines once they’re safely away from the fire and headed back to the station.