In: Psychology
discusses trait theories and the evidence for and against the hypothesis that personality traits are inherited.
Traits are relatively stable characteristics that cause individual's to behave in a certain manner.
Trait theories of personality are less concerned with the explanation for personality development and changing personality than they are with describing personality and predicting behviour based on that description.
Gordon Allport scanned the dictionary for words that could be traits. He found 18000 words and then paired them down to 200 traits.
Raymond Cattell defined two types of traits which are source traits and surface traits.
Surface traits are the personality characteristics that are easily seen by other people. Source traits are those more basic traits that underlie the surface traits.
Example: shyness, disliking crowds might be surface traits related to the more basic trait of introversion, a tendency to withdraw from excessive stimulation.
Using factor analysis, Cattell discovered 16 source traits. The Sixteen Personality Factor (16 PF) is based on 16 source traits.
Mc Crae & Costa gave the big five factor model of personality , the 5 dimensions were : Openness, Conscientiousness, Extraversion, Agreeableness and Neuroticism.
The field of Behaviour Genetics is devoted to the study of just how much of an individual's personality is due to inherited traits.
Minenesota twin study have revealed that identical twins are more similar than fraternal twins or unrelated people in intelligence, leadership abilities, the tendency to follow rules, and the tendency to uphold traditional cultural expectations ( Bouchard, 1997), nurturance, empathy and assertiveness (Neale et al.,1986). This similarity holds even if the twins are raised apart.
Adoption studies have confirmed what twin studies have shown: Genetic influences account great deal of personality development regardless of shared or non shared environments (Hershberger et al, 1995).