Electromagnetism-like Mechanism Heuristic (EM) intends to make an analogy with the attraction-repulsion mechanism for sampling solutions.

However, the electromagnetism mechanism of attraction-repulsion is actually not realized by comparing the fitness of two points. Hence in the Multiagent Optimization System (MAOS), the key behavior of EM algorithm is explained by the Social Impact Theory (SIT), which declares that the likelihood of a person responding to a social influence will increase with: a) strength: how important the influencing person is to you; b) immediacy: how close the person is to you at the time of the influence attempt.