Emotional Intelligence (EI), often measured as an Emotional Intelligence Quotient (EQ), describes an ability, capacity, or skill to perceive, assess, and manage the emotions of one's self, of others, and of groups. As a relatively new area of psychological research, the definition of EI is constantly changing.
Defining emotional intelligence
There are a lot of arguments about the definition of EI, arguments that regard both terminology and operationalizations. The first published attempt toward a definition was made by Salovey and Mayer (1990) who defined EI as “the ability to monitor one's own and others' feelings and emotions, to discriminate among them and to use this information to guide one's thinking and actions” 
Despite this early definition, there has been confusion regarding the exact meaning of this construct. The definitions are so varied, and the field is growing so rapidly, that researchers are constantly amending even their own definitions of the construct. . Up to the present day, there are three main models of EI:
The ability - based model
Mayer and Salovey's conception of EI strives to define EI within the confines of the standard criteria for a new intelligence. Following their continuing research, their initial definition of EI was revised to: "The ability to perceive emotion, integrate emotion to facilitate thought, understand emotions, and to regulate emotions to promote personal growth" .
The ability based model views emotions as useful sources of information that help one to make sense of and navigate the social environment . The model proposes that individuals vary in their ability to process information of an emotional nature and in their ability to relate emotional processing to a wider cognition. This ability is seen to manifest itself in certain adaptive behaviors. The model proposes that EI includes 4 types of abilities: 
1. Perceiving emotions - the ability to detect and decipher emotions in faces, pictures, voices, and cultural artifacts- including the ability to identify one’s own emotions. Perceiving emotions represents a basic aspect of emotional intelligence, as it makes all other processing of emotional information possible.
2. Using emotions - the ability to harness emotions to facilitate various cognitive activities, such as thinking and problem solving. The emotionally intelligent person can capitalize fully upon his or her changing moods in order to best fit the task at hand.
3. Understanding emotions - the ability to comprehend emotion language and to appreciate complicated relationships among emotions. For example, understanding emotions encompasses the ability to be sensitive to slight variations between emotions, and the ability to recognize and describe how emotions evolve over time.
4. Managing emotions - the ability to regulate emotions in both ourselves and in others. Therefore, the emotionally intelligent person can harness emotions, even negative ones, and manage them to achieve intended goals.
This definition is part of a series that covers the topic of Emotional Intelligence. The Official Guide to Emotional Intelligence is Reldan S. Nadler, Psy.D. Dr. Nadler, educated as a clinical psychologist, has become a world-class executive coach, corporate trainer and author. He is the president and CEO True North Leadership, Inc. an Executive and Organizational Development firm. Dr. Nadler brings his expertise in Emotional Intelligence to all his keynotes, consulting, coaching and training. A licensed psychologist and Master Executive Coach, Dr. Nadler has been working for more than 30 years with top executives and their teams to become “star performers.” He is the author of two best-selling leadership and team performance books, and is a sought-after speaker and consultant on leadership, emotional intelligence, teambuilding, executive coaching, and experiential learning.
Additional Resources covering Emotional Intelligence can be found at: