They dilate in response to stimulation by the sympathetic nervous system.
My teacher told me that once, I believe that it is all bullsh*t
They also dilate in response to darkness, alcohol, and many types of drugs. So perhaps you were just drunken, stoned, and in a room with inadequate lights :p
Do people's eyes really dilate when you love someone?
I never really believed it but I was at my girlfriends place and I went to the bathroom and I got freaked out... my pupils were the size of cannon... Show More