Final answer:
The twin-study method is used by psychologists to discern genetic and environmental influences on personality traits. The method has shown that genetics play a significant role. However, personality is shaped by a combination of genetic factors and environmental influences.
Therefore, d) all of these are correct.
Step-by-step explanation:
Psychologists interested in studying personality might use the twin-study method in order to a) separate environmental from genetic influences, b) determine how much of our personality is inherited from our parents, and c) determine how much of our personality is the result of experience. Therefore, d) all of these are correct.
The twin-study method is crucial for understanding the relative impacts of nature and nurture on personality traits. Studies like the Minnesota Study of Twins Reared Apart have revealed that identical twins, whether reared together or apart, often exhibit very similar personalities, which indicates a genetic component to personality. However, while this suggests a strong genetic basis, it is also clear that no single gene is responsible for any trait; rather, a complex interplay of genetic factors and environmental influences shapes our personality.