Bullying is not usually perpetuated by an individual alone, while it is a possibility. Usually however, for the bullying to sustain, the main person instigating or indulging in active bullying may rely on others, who aid the primary person(s) engaging in bullying by acts of reinforcement (laughing, joining in, isolating the person who is experiencing the bullying, condoning and justifying the behaviour) and thus the Bullying expands to include a group.

This is referred to as mobbing. Mobbing has the potential to be more harmful to a worker’s psychological well-being and career than one-on-one bullying.