Thanks for sharing, Elicia! Fascinating read, I think it's often forgotten that the way animals communicate their desire for sex is typically through the genital regions. When you don't have speech, you haven't really got much else. When we evolved to stand up, this actually benefited the females when looking at males genital region, because standing up makes them more prominent. However, it has the absolute opposite effect on women's.

Inevitably, as you say, this created a problem because it meant the males could easily communicate their desire for sex to the females, and the females could easily read the males desire for sex, but the females lost their ability to easily communicate their desire for sex to the males and as such the males lost their ability to read the females desire or not for sex.

It does seem highly probable that breasts were the solution to this conundrum.

What always fascinates me is those experiments that look into just how often people unwittingly look at male crotches, female breasts and female asses. Shows you how close we still are to our ancestors.