The academic definition of emotional intelligence
Emotional Intelligence (EI) was first defined in a scholarly paper by Peter Salovey and John Mayer in 1990. According to their Four-Branch Model, emotional intelligence is composed of four distinct abilities. (1) Perceiving Emotions: the capacity to identify one's own feelings and those of others accurately. (2) Using Emotions: the capacity to harness feelings so that they facilitate thinking, judgment, and problem solving. (3) Understanding Emotions: the capacity to grasp what causes an emotion, how emotions change over time, and how they blend into complex states such as resentment or bittersweet nostalgia. (4) Managing Emotions: the capacity to regulate one's own emotions and to influence the emotions of others appropriately. This academic definition differs from the popular notion of "EQ" that Daniel Goleman spread through his 1995 trade book; the Salovey-Mayer version is deliberately narrow, treating emotional intelligence strictly as a mental ability that can be right or wrong on a given task. Goleman's model is far broader, taking in self-awareness, self-management, social awareness, relationship management, and motivation, and it therefore mixes stable personality traits together with abilities. Keeping the two frameworks apart matters, because claims about what emotional intelligence predicts depend heavily on which definition is being used.
How emotional intelligence is measured, and how people differ
There are two broad approaches to measurement. Ability-based instruments, of which the MSCEIT (Mayer-Salovey-Caruso Emotional Intelligence Test) is the best known, present respondents with emotion-related problems to solve and score the answers for correctness, much as an intelligence test does. Trait-based instruments such as the TEIQue and the EQ-i instead use self-report questionnaires and effectively measure a person's confidence in their own emotional functioning. The two families do not correlate strongly with each other, which suggests they may be tapping different constructs rather than two versions of one thing. In relation to the Big Five, trait EI correlates positively with agreeableness, extraversion, and conscientiousness, and negatively with neuroticism. Ability EI shows much weaker associations with the Big Five and behaves as a more independent construct. As for sex differences, women tend to score slightly higher on ability EI, though the effect size is small. Emotional intelligence also rises gradually with age, which indicates that it is an ability developed through accumulated experience rather than a fixed endowment settled early in life.
Emotional intelligence and the quality of a relationship
Emotional intelligence is an important predictor of relationship satisfaction. People high in emotional intelligence read a partner's feelings accurately, respond to them appropriately, and express their own emotions constructively, so the overall quality of their communication is higher. Emotional intelligence is generally thought to go together with the ability to resolve conflict, and to make it less likely that a couple falls back on Gottman's Four Horsemen. The managing-emotions branch in particular contributes directly to preventing emotional flooding and to recovering from it once it has begun. Where both partners are high in emotional intelligence, constructive patterns of interaction tend to form readily. Even when only one partner is high, that person can serve as a model, and emotional intelligence may develop within the relationship itself. Emotional intelligence is less a fixed endowment that sorts people into winners and losers than a skill two people can build together. When a partner's tone stings, pausing before you answer and naming the one thing you actually reacted to is a small habit, but repeated often enough it changes both how accurately you read feelings and how you convey your own.