Loyalty to a group can be a force for good, but it can also warp our ethics. Berkeley Haas research co-authored by Angus Hildreth, PhD 16, now an assistant professor at Cornell University, found that students who described themselves as loyal cheated less during the beginning of an experiment. But when the importance of beating rivals to win a cash prize was stressed, a darker side emerged.

Multilevel marketing companies do have some similarities to cults, said Prof. Jennifer Chatman, Paul J. Cortese Distinguished Professor of Management. "It's the way they use personal relationships to recruit as well as target people who are at a vulnerable point in their lives," she said. "Even more than it being a job and a source of income, it's a source of relationship gratification."

As shoppers of the net, we tend to overestimate our ability to be rational in the face of of online nudges and "dark patterns." "It’s common for people to say, 'Oh, I meant to do that,' when in fact they were manipulated," said Prof. Don Moore, Lorraine Tyson Mitchell Chair in Leadership and Communication. But he adds that nudges can be pro-social as well, like reminding people to register to vote.