They then examined the anthropological literature and counted the number of cultures in which this collection of features was described. To their surprise they found that it was described in 90 per cent of the cultures on record. The philosopher Paul Griffiths has argued that there are not two kinds of emotion but three. This is fine so long as we realise that these categories are not black and white. They are not so automatic and fast as basic emotions, and nor are they universally associated with a single facial expression.
Love is a case in point.
Although love at first sight is possible, it is relatively rare. It seems much more common for love to grow gradually over the space of several days. Contrast this with the emotion of fear, which typically overtakes a person in a matter of milliseconds. And, while fear is easily recognisable by its typical facial expression, there is no specific facial expression associated with the emotion of love. This perhaps explains why some of us are incapable or not very good at expressing our love.