That's not what I read! I'll try to explain this with logic. (PS: A good read will be Allan and Barbara's pease book on body language. Good manual for everyone, got me started 2 years ago, covers the basics, and it's funny too.)
To illustrate my point, first you must admit that:
The brain has a mirror... neuron. (Idk the name!

)
Basicly what it does is that it mirrors what you see. Frequently.
That's why you mirror a smile or a yawn...
And second:
It is predefined in your brain that dilated pupils are more attractive then normal ones! Need an explination? Use google images and see for yourself!
Nice secret, eh? That's why people tend to like blue eyes... It's easier to notice the pupiles dilactate in them. Just a theory. :crazy:
So that is the explination why candle light dinners are a perfect atmosphere for romance!
Pupils dilactate from low light... And it makes you look nice!
And what if you are attracted to a girl and keep making EC?
She will mirror you... And her pupils will dilactate too!
Which will make you even more excited!
Don'te believe me?
Search for dilacted pupils and look at them for 1/2 mintues and look at yourself in a mirror. And notice your wide pupils!
Then look at non dilacted pupils... Yours will shink too!
A nice cycle! Nature helps us!
So they come from:
You're attracted.
You need more light. (In dark places.)
You're mirroring someone.
Effects:
You can see her IL.
You look sexy!