1.   Even in people who are totally blind and have no perception of light, some have normal hormonal responses to bright light, the researchers found.

2.   That means that a mother who is nursing a baby has a very different hormonal response from one who is nursing a toddler.

3.   This triggers a hormonal response that tells them to make lots of flower buds to produce lots of seeds and thus keep their genes going.

4.   When the brain realizes we are smiling, it releases the hormonal response that usually accompanies our state of feeling happy.