Personality is often described as simply one's distinctive personal character. However, personality is a much more complex area in which biologists and psychologists have pondered over for many years. It can be defined as the relatively unchanging and distinctive patterns of one's thoughts, behaviors and feelings, which in turn produce a person's own style of interacting with the physical and social environment. There are two main factors that affect one's personality, environmental and biological factors (commonly referred to as the nature versus nurture approach to personality). Lets then focus on the latter, and attempt to find out to what extent personality is biologically based. In order to this, certain evidence such as the field of behavioral genetics, studies of frontal lobe brain damage, and Eysenck's well accredited theory are required to be reviewed and evaluated. .
The first point that needs to be addressed is the field of behaviour genetics. Behavioral geneticists study the inheritance of behavioral characteristics by combining the fields of psychology and genetics. Their studies show us that psychological traits and characteristics can be transmitted from parent to offspring. These characteristics include such things like aggressiveness, anxiousness and the ability to reason. A research study called the Minnesota Study of Twins Reared Apart, involving 30 pairs of identical twins, began at the University of Minnesota in 1981. It was believed, based on the fact that these twins had the exact same genetic makeup, they would in fact have similar personalities, despite being raised in different environments. .
This was evident in the vast majority of the identical twins, but perhaps no more than Jack Yufe and Oskar Stohr. This pair had been raised in dramatically different environments, yet still displayed remarkable similarities.