There are many reasons for this concept some of them related to the cognitive part and others related to personality part.
Trait theories clearly state that "people have certain inherent traits which determine their behavior". (Brooks, 2009, P.45)
The different education and experience relate to the cognitive part while the personality traits differences relate to the personality part.
Personality means "specific characteristics of individuals which may be open or hidden and which may determine either commonality or differences in behavior in an organization" (Brooks, 2009, P.43)
In order to assess the effect of these personality trait differences on the individual behavior an assessment model was developed. It divided the personality traits into five main groups: (Brooks, 2009)
Openness: it is the perception for art, imagination, openness to new experience. People who have high rate in this category are more creative and more aware of their feeling than those with low.
Conscientiousness: it reflects to what extend the person is organized and achieve more than the expectation and has a planned behavior more than the spontaneous behavior. The opposite trait is unconscientiousness.
Extraversion: this trait reflects positive emotions, engagement with external world and being with other people and seeking every opportunity for excitement, showing themselves in groups and attracting the attention of other people to their talks. The opposite trait is introvert.
Agreeableness: is the tendency for people to cooperate with other rather than to be suspicious. Agreeable people tend to go along with other, willing to compromise their interests with others and are friendly. They view other people to be honest, decent and trustworthy. The opposite of this trait is disagreeable people.
Neuroticism:
References: * Rose, R. Ramalu, s., Uli, J. & Kumar, N. (2010), Expatriate Performance in Overseas Assignments The Role of Big Five Personality, Asian Social Science, Vol. 6, No. 9, pp: 104-113, [online] available from http://ehis.ebscohost.com.ezproxy.liv.ac.uk/eds/pdfviewer/pdfviewer?sid=462f7aac-df2b-43ff-910f-80403a0b4d88%40sessionmgr111&vid=2&hid=109, accessed on 5/1/2012 * Brooks, I. (2009), Organisational Behaviour: Individuals, Groups and Organisation, Pearson Education Limited, Fourth edition. * Personality Inventory, (2012), [online] available from, http://test.personality-project.org, accessed on 5/1/2012 * Klaus, T. (2012), Five-Factor Model of Personality and Job Satisfaction: The Importance of Agreeableness in a Tight and Collectivistic Asian Society, Applied Psychology: An International Review; Jan2012, Vol. 61 Issue 1, p114-129, 16p, [online], available from, http://ehis.ebscohost.com.ezproxy.liv.ac.uk/eds/detail?sid=9e846794-1ced-415a-97f1-bbb13d0af80b%40sessionmgr114&vid=1&hid=109&bdata=JnNpdGU9ZWRzLWxpdmUmc2NvcGU9c2l0ZQ%3d%3d#db=a9h&AN=67651075, accessed on (5/1/2012).