How Alice's tears are for you, as well as for her

Sitting here jetlagged to hell in San Diego (more later) looking at the heavy grey sky, I've decided it's time to talk tears.

While many mammals and most primates have tear ducts and use them to heal, salve or clean the delicate surfaces of their eyes only Humans cry tears of emotion.

Somewhere in the last hundred or so millenia, we have developed this ability to amplify our ability to communicate what our body reveals of our sensations and internal experiences (primates also howl or skulk when in pain or scared etc) so that it is visible on our streaky faces.

Crying is both a sign to the cryer that things are past the worst (they deliver certain emotional/physiological benefits for the cryer which heal and soothe - ref when I get home) and also a sign to the observer that things are as bad as they seem for the crier. It adds another layer of sophistication to the body- (and other) language which can't help but reveal information about those arounds. In other words, crying is a social or Herd function, enabling more accurate information about what is going on in the primary context of our lives.

It also has a behavioural imperative contained within: it tends to encourage us to respond with empathy, sympathy and comfort. We all know the experience of feeling the necessity to dry and wipe away a child's tears and so it is with adult ones. Of course, just as with small children, we learn that some individuals get tearful at lower levels of pain/distress while others almost never get to big wet salty tears; some again, try to manipulate us with their tearfulness...

However good we are at telling real from crocodile tears, the interesting thing about the salty secretion dripping down your cheeks is its primarily Social - or HERD - Function