Personality Traits

Research Project: Genetic vs. Environmental influence on Personality Traits

Reason: Personality traits are different among different people. Some people are introverted and some people are extroverted. Some people are open-minded and some people are close-minded. Some people tend to be happy and optimistic, and some people tend to be sad and pessimistic. Even though now there is a general consensus that personality traits are shaped by both genes and the environment, scientists have debated whether the influence of genes or the environment is greater for a long time. We would like to contribute to our understanding of the genetic and environmental influences on personality traits. In this research, we will try to determine whether genes or the environment have a greater influence on human personality traits by analyzing data from research on personality traits that has been conducted in the past. The most promising research methodology in determining the relative importance of nature and nurture in shaping personality traits is twin studies. Comparing monozygotic twins and dizygotic twins can allow us to assess the importance of genes since monozygotic twins are genetically identical whereas dizygotic twins are only 50% related. Comparing monozygotic twins reared together and reared apart can allow us to determine the relative influence of different environments. Since identical twins are genetically identical, personality trait differences in identical twins that were reared apart must be due to environmental influences.

Hypothesis: Personality traits are mainly shaped by genes rather than the environment.

Null Hypotheses: 1. Dizogotic twins raised together have the same concordance in personality traits as monozygotic twins. 2. Monozygotic twins raised apart have the same concordance in personality traits as digozotic twins. 3. Monozygotic twins raised together should have higher concordance in personality traits than monozygotic twins raised apart.

Procedure:

1. Collect original research papers on twin studies of personality traits

2. Combine data from the various original research papers
3. Perform statistical analysis on the combined data
4. Calculate the relative importance of genetic and environmental influences on personality traits

After this initial research proejct, we will use the following questionnaire to collect original data on personality traits among twins.