Game theory offers an alternative approach of measuring a sample population's behavior in a suite of games with varying payoffs. The study below suggests most people's behavior patterns fall into just 4 major groups, with a 5th group (~20%) that seems to just make random choices. Even more surprisingly, these patterns seem to be established early in life and to be independent of socio economic factors. In that study, the largest cohort was found to be willing to experience a loss as long as the counterparty suffered a greater loss, and I suspect that would probably correlate well with the 'sadistic' cohort mentioned in OP's study.