If we understand human brain in a simpler way : It is divided into two parts :
Thinking brain is all about analysis, intelligence, thoughts, decision making and all the other activities we can think about in which brain is used. For which the IQ is measured.
However, emotional brain is all about containing emotional memories, reflex in extreme emotions, or anything that comes to our mind which involves emotions or in layman language, any heart related matter.
We always have been measuring IQ as a means for achieving success but the question is : Is it only IQ which is crucial for decision making? Don't our emotions play any role while making any decision? Is thinking rationally only means thinking only using facts and profits and not how that decision can impact us emotionally ?
Our view of human intelligence is very narrow. Our emotions play a far greater role in thought, decision making and individual success than we actually acknowledge.
Emotional intelligence includes self awareness or emotions, impulse control, persistence, zeal and motivation, empathy and social deftness. These are the qualities that mark people who excel: whose relationships flourish, who takes failure in a better way, who are the stars of the workplace, who are liked more in the society.
Even before we knew how to think , we knew how to feel. A kid knows to cry when separated from mother, a kid knows the toy to pick which he enjoys a lot and not the toy which is most expensive or rational.
Emotional lessons a child learns actually sculpt the brain's circuitry and emotional intelligence can be nurtured and strengthened in all of us.
As said by Good housekeeping while reviewing Emotional Intelligence book by Daniel Goleman “Forget IQ. Brains may come in useful, as may social class and luck, but as a predictor of who will succeed in any area of life, EQ is the thing to worry about.”
If I sum up understanding emotional intelligence using an example it would be Aristotle's famous quote:
Anyone can become angry- that is easy. But to be angry with the right person, to the right degree, at the right time, for the right purpose, and in the right way- this is not easy.
This is exactly what emotional intelligence teaches us and guided us about.