Organism-environment correlations: when an organism selectively shapes its environment, and in turn is affected by the environment's response to that particular organism.

• Specific children may be more likely to seek out environments that improve their reading, such as choosing reading as a hobby over sports, or asking their parents for books as birthday presents.

Passive organism-environment correlations: the relationship between the type of organism and environmental that is not due to the organism’s active selection of the environment.

• One example is genotypes, as some children may be more genetically inclined to be good readers. Additionally, early school environment greatly affects reading experience, which is (typically) not able to be selected for.