Reaction range in psychology refers to how people have different reactions and attributes, although they may have had the same stimuli and environment as others. For example, two twins can grow up in the same environment, yet their IQs can be vastly different.
Environment places a huge role in scoring reaction range. Those in higher-quality environments do tend to perform better than their peers in lower-quality environments. However, this is not always the case. Reaction range can be at the heart of age-old arguments between heredity and environment, also known as nature versus nurture. Behavioral psychologists disagree widely on these issues.