What examples of correlational studies & statistics are cited in the sources

What examples of correlational studies & statistics are cited in the sources why are they correlations and not experiments (remember, correlation does not equal causation)?

3.  Some of the sources allude to the use of classical and operant conditioning and schedules of reinforcement in social media usage. How do learning theories apply to social media usage? Address each of the following and cite specific examples from the sources:

a.     Classical Conditioning

b.     Operant Conditioning