The American psychologist, Gordon Allport (1937) looked at these two major ways to study personality, the nomothetic and the idiographic. Nomothetic psychology looks for general laws that can be applied to many different people, such as the factor of sensing, or the trait of openness.
Personality is thought to be determined largely by both genetics and nature, by environment and experiences, or by combination of the two. There is evidence for all possibilities. Modern research suggests that most personality traits are based on the influence of both nature and nurture.
The nomothetic approach in regard to the nature-nurture debate assumes that personality is mainly inherited, as opposed to being nurtured. The approach involves the study of types or traits of one's individual in personality research and assessment.
A trait is a repetitive pattern such as always being untidy or late. Theorists generally assume that traits are fairly stable over time, and that traits are different among individuals.
A type is defined by the dominant preference. People are either extrovert or introvert. The two traits are discontinuous, i.e. there is no in between. This means people may be extrovert or introvert on a continuous scale. The idea is that we all possess personality traits in pairs of opposite characteristics.
The nomothetic approach sees people as unique in their combination of traits, only within a certain paradigm. People differ only on the amount they have on each trait.
References: Huczynski, A. A. and Buchanan, D. A. (2007) Organizational behaviour: An introductory text. 6th ed., Harlow: Financial Times Prentice Hall. Google book search. An introduction to theories of personality. [online] (accessed 01/12/2008) http://books.google.co.uk/books?id=Ks0DzfrQIW8C&pg=PA262&lpg=PA262&dq=nomothetic+approach+personality&source=web&ots=Oi10-hTY5e&sig=ToUWUQOv8zJqTflPBl3kT5_50Kc&hl=en&sa=X&oi=book_result&resnum=1&ct=result#PPA263,M1Simply Psychology. Psychological debate. [online] (accessed 01/12/2008) http://www.simplypsychology.pwp.blueyonder.co.uk/nomotheticWilderdom. Personality Traits: Idiographic vs. Nomothetic. [online[ (accessed 02/12/2008) http://wilderdom.com/personality/traits/PersonalityTraitsIdiographicNomothetic.htmlCran Psyche. Idiographic versus nomothetic approaches to psychology. [online] (accessed 02/12/2008) http://www.cranepsych.com/Psych/Idiographic_versus_nomothetic.pdfCrozier, G. (2000) Test Your Personality., London, Hodder & Stoughton