running head~psychology

Personality traits that are consistently and strongly associated to SWB are extraversion and neuroticism (Diener and Lucas, 1999). The latter, however, will not be looked at in this particular study, but our interest lies in the direct relationship between extraversion and SWB. .
             Genetics have also been proven to influence most personality traits. Extraverts may seek stimulation because they have relatively low brain arousal in comparison to introverts who may avoid stimulation because their brain arousal is high (Myers, 2001). It would then seem effective to evaluate ones personality with the aid of a PET scan, However, this would be too costly, and alternatively researchers assess personality traits by administering personality inventories-questionnaires on which people respond to items designed to measure a large range of selected personality traits (Myers, 2001).
             In one study by Costa and McCrea (1980), they looked at extraversion and neuroticism's influence on subjective well- being. They used a large sample of male white veterans, and collected data through mailed out questionnaires. However, this technique could have resulted in a loss of substantial amounts of data because there was consecutive decrease in the response rates over the time period the experiment took place. Furthermore, the questionnaires were filled without supervision so the participants could have taken a longer period of time to answer the questions before they permitted, and they might contribute to altered data. Costa and McCrea (1980) took their study another step forward by having it span a period of ten years. This would reinforce that adults are stable in their personalities, and momentary factors like whether or not temporary moods do somehow, affects one's life satisfaction momentarily, but across one's life span subjective well-being remains stable (Diener and Lucas, 1999).
             Another study conducted by Diener and Fujita (1990) ruled out other underlying factors that may cause extraverts to be happier such as: more social contact, societal and environmental influences, and social desirability bias.