I want to start today by putting up a bright yellow caution sign on the ground ahead of us.

When we explain something scientifically, some people, maybe not you, feel we've stripped

it of meaning, I want to say that this is not true. Why you evolved to feel a certain way in most

contexts has minimal bearing on the worthiness of the feelings themselves.

You already know this in some scenarios. For example, you know the reason you like the taste of fruit is because you are an ape.

And apes evolved to adore the taste of fruit because, in our ancestry, the apes who really liked eating fruit

were more motivated to forage for it, and therefore less likely to starve. So fruit-adoring

apes survived to reproduce at a higher rate, and now almost everybody quite likes a fruit salad.

You already knew that.

And yet, this evolutionary knowledge has never affected your enjoyment of an apple.

Today, I've brought on an expert who is going to fully explain romantic love for all of you.

This is an appropriately timed episode, recorded just a week before Valentine's Day,

and we're publishing it now a week after.

And by the end of this episode, I promise you are going to understand the evolved reasons you fall in love, the same way you already understood the evolved reasons you like fruit.

So here's the caution sign.

Don't let this knowledge affect the meaningfulness of romance for you.

Just enjoy the apple.

And I guess I'll put up another caution sign before we go too deep, obviously.

And talking about romance and love from a biological perspective,

we're going to have to touch some adult topics.

Now, I don't believe any of this is particularly scandalous,

but I do believe that it's up to parents to decide what their kids get to hear.

...