Marston's other psychological work resulted in the DISC theory, a method of behavioral assessment that is still in use today. DISC stands for the four categories of human interaction: Dominance, Influence, Submission and Compliance. Basically, Marston believes that in a relationship, one person is naturally more likely to either be active (dominant/influential), the other passive (submissive/compliant), which can be good or bad. In a bad situation, the active person forcibly dominates the passive person into complying. In a good situation, the active person lovingly influences the passive person into willingly submitting.
His fascination with the power dynamics of human relationships parlayed into an interest in bondage or "love binding," as he called it, which, if you ever read the WWII-era Wonder Woman comics, is completely obvious. Seventy-some-odd years before 50 Shades of Grey, Wonder Woman was getting tied up in ew and inventive ways at least once every issue. Marston didn't see bondage as necessarily sexual; he believed that bondage was a way to teach people how fun it could be to obey authority. Unwilling bondage by bad guys = bad, Wonder Woman doesn't put up with that. Consensual bondage by her fellow Amazons = fun!