Sensory manipulation. As with ritualization, sensory manipulation involves two stages. First, a coercive behaviour emerges. Then, that behaviour may become a signal, and the interaction may become communicative, if the coerced individual (the reactor) gains from being coerced. In contrast, if being coerced is costly, then the system will collapse. If being coerced is neutral, then the system will remain stable, but we cannot label it communicative.