The EU foreign policy chief was credited with using great 'emotional intelligence' in the Iran nuclear talks. But what do we know of this relatively new psychological concept? And do women have higher EI than men?

Much of the credit for this weekend's historic defusing of the Iranian nuclear issue, hailed as one of the great diplomatic triumphs of the new century, has rightly gone to Lady Ashton, the European Union's high representative for foreign affairs and security policy, and to the high degree of "emotional intelligence" she is said to have brought to the task of patiently brokering a deal as important as it was considered impossible.

At its most basic, emotional intelligence could be said to boil down to "getting on with people". A relatively recent psychological concept whose precise meaning is still disputed, EI is defined rather more scientifically as the ability to perceive, identify, evaluate and control emotions in oneself and, critically, others. Some experts claim it is at least as important as a person's intelligence quotient; others argue that the key abilities attributed to it are actually skills and should not be referred to as intelligence at all. It follows that there is also dispute about whether emotional intelligence can be learned and strengthened, or whether people are born with it.

The term's first scientific appearance seems to have been in a doctoral thesis in 1985, but the man who really popularised it, in a string of highly successful self-help books starting with the 1995 bestseller Emotional Intelligence: Why it Can Matter More Than IQ, was the New York Times science writer Daniel Goleman.

Goleman defines the five core components of emotional intelligence as self-awareness (recognising and understanding personal moods and emotions and drives, as well as their effect on others); self-regulation (controling or redirecting disruptive impulses and moods, and thinking before acting); motivation (harnessing emotions to achieve goals and persevere); empathy (sensing the emotions of others) and social skills (managing relationships, inspiring others and getting them to respond as you would like). The leading academic researchers in the field, Peter Salovey of Yale and John D Mayer of the University of New Hampshire, use different terminology, defining the four key elements of EI as perceiving, using, understanding and managing emotions.

And do women have higher EI than men? According to Goleman, they do, but not across the board. "There are many tests of emotional intelligence," he says, "and most seem to show that women tend to have an edge over men when it comes to these basic skills." But there is a nuance: the tests show women tend to excel at sensing emotion (empathising), while men tend to be good at managing emotion (ie compartmentalising or, sometimes, ignoring it). Although, Goleman diplomatically adds, that is not true of all men and all women: "There's a lot of overlap." An observation with which Ashton would surely agree.