【英文原文】
Smile! You’ ll Feel Better
As the song says,smiling when you’re feeling blue appears to put you in a rosy mood.At least that’s the theory set forth by Robert B.Zajonc,Ph.D.,director of the Institute for Social Research at the University of Michigan.
When you smile,two things happen:You breathe through your nose,and you exert pressure on the veins1) in your face.Both of these activities result in cooler blood entering the region of the brain known a s the hypothalamus2) ――which,Zajonc believes,causes the release of chemicals that can suppress pain and /or help you fee l better.When you breathe through your nose,you bring cool air into your nasal3) passages,which cools the veins and t he blood flowing through them.And when you use the“smile muscles”at the corners of your mouth,you change the direction of the blood flow inside your face in such a way that it causes the temperature of the blood to drop.
Cooling the blood may also inhibit4) the release of serotonin5),thought to be related to depression,and promote the release of endorphins6),which suppress pain and give you a lift.
All this may be one reason we enjoy kissing so much.Notes Zajonc,“When you kiss,you have to breathe through your nose,because your mouth is otherwise occupied.”