If you want an exciting first date this Valentine's Day, forget dinner and a screening of "Wuthering Heights".
Try zip-lining instead.
This is the advice of Justin Garcia, an evolutionary biologist and head of the Kinsey Institute,
one of the world's best-known centres of research into sex.
A day of climbing hills to throw yourself off cliffs lets you "walk and talk
while experiencing something novel and thrilling together".
Thus, you will get to know each other better.
And because of a psychological principle known as "misattribution of arousal",
your companion may start to associate you with thrilling feelings.
"Yes, this is how sexologists approach first dates," says Dr Garcia.
Many species reproduce sexually.
Homo sapiens is the only one to write books worrying about how the process is changing.
Humankind is facing an "intimacy crisis", argues Dr Garcia in "The Intimate Animal".
Globally, one person in four is lonely.
Without strong relationships, people live less cheerfully and die earlier.
A survey in America found
that 98% of people believe good, intimate relationships are a key element of a satisfied life.
Part of the problem is the mismatch between the world
in which our brains evolved and the one in which people now search for love, contends Dr Garcia.
In his telling, the two greatest changes to human courtship