Final answer:
The statement is true; researchers measure genetic contributions to personality through studying the temperaments of infants and children, and by conducting heritability studies on twins and adopted individuals, which include analyses like the Minnesota Study of Twins Reared Apart.
Step-by-step explanation:
The statement that researchers measure genetic contributions to personality in two ways is true. These two methodologies are:
- Studying the temperaments of infants and children, and
- Conducting heritability studies on twins and adopted individuals.
Temperament is seen very early in life and is believed to have a biological basis. Thomas and Chess characterized infants into three temperaments: easy, difficult, or slow to warm up, indicating that personality may be influenced by genetic factors. Additionally, psychologists Hans and Sybil Eysenck also linked personality differences to genetics through the dimensions of extroversion/introversion and neuroticism/stability.
Moreover, the results from the Minnesota Study of Twins Reared Apart have significantly contributed to the understanding of genetics and personality. This study, which followed 350 pairs of twins, found that identical twins—whether raised together or apart—exhibited very similar personalities, supporting the idea that some personality traits have a high heritability ratio. Heritability studies in twins, particularly identical twins raised apart, offer valuable insights into how genetics as opposed to environment shapes our temperaments, preferences, and abilities.
Behavioral geneticists utilize twin and adoption studies to discern the impact of genetics and environment on human behavior, leading to an understanding that individual differences arise through this gene-environment interaction.