Personality is best described as what makes up a person, their traits and individual differences that make them unique. There has been much research undertaken as to what actually causes a personality to develop whether it is nature (genetically inherited) or by nurture (the environment) research has shown that it is a combination of both and this will be examined in this essay.
Human society is complex and this presents researchers with difficulties in measurement of the environmental effect and to define exactly what causes personality. Psychologists and behaviour geneticists have tried to estimate contributions made by genetics and the environment to individual differences through heritiability. Heritability is when research has been carried out to establish the contributions of genetics and the environment to a population sample. This is based on knowing the birth relationship (genetic relatedness), measuring the trait in question and making comparisons between groups with differing levels of genetic relatedness.
The amount of variability in a trait or physical measurement within a population is accounted for to show how much has been inherited (genetically) and the percentage remaining is the environmental contribution.
The study of twins is the most commonly used design in behavioural genetics .Monozygotic (MZ)twins developed from a single fertilized ovum and possess identical genes. Dizygotic (DZ) twins develop from two separate fertilized ovums and have different genes. It would seem to indicate that MZ twins should have more similarities than DZ twins. Researchers use formula to convert associations between twins into heritability estimates. For example the estimated heritability of neuroticism is approximately 30 per cent which indicates the remainder as environmental. This study assumes the environment for each twin is equal, which would probably indicate that each MZ twin had been treated similarly and have closer bonds than DZ. Behaviour geneticists compared MZ...