The two types of explanations attempt to account for this difference are instrumental theories and temperamental theories.
The instrumental theory suggests that extraverts end up making choices that place them in more positive situations and they also react more strongly than introverts to positive situations.
In other words, the study focused on the benefits and drawbacks of introverts (people who are shy, socially inhibited and non-aggressive) acting extraverted, and of extraverts acting introverted.
After acting extraverted, introverts' experience of positive affect increased whereas extraverts seemed to experience lower levels of positive affect and suffered from the phenomenon of ego depletion.
Ego depletion, or cognitive fatigue, is the use of one's energy to overtly act in a way that is contrary to one's inner disposition.
When people act in a contrary fashion, they divert most, if not all, (cognitive) energy toward regulating this foreign style of behavior and attitudes.Personality is not stable over the course of a lifetime, but it changes much more quickly during childhood, so personality constructs in children are referred to as temperament.Temperament is regarded as the precursor to personality.Many approaches have been taken on to study personality, including biological, cognitive, learning and trait based theories, as well as psychodynamic, and humanistic approaches.Personality psychology is divided among the first theorists, with a few influential theories being posited by Sigmund Freud, Alfred Adler, Gordon Allport, Hans Eysenck, Abraham Maslow, and Carl Rogers.It measures personality based on Cattell's 16 factor theory of personality.Psychologists also use it as a clinical measuring tool to diagnose psychiatric disorders and help with prognosis and therapy planning.Trait-based personality theories, such as those defined by Raymond Cattell define personality as the traits that predict a person's behavior.On the other hand, more behaviorally based approaches define personality through learning and habits.The Big Five Inventory is the most used measuring tool because it has criterion that expands across different factors in personality, allowing psychologists to have the most accurate information they can garner.Personality is often broken into statistically-identified factors called the Big Five, which are openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism (or emotional stability).