Emotions have attracted much interest in the Multi Agent Systems community, mainly due to their significance in creating simulations that more accurately predict crowd behaviours. Undoubtedly, infusion of agents with artificial emotions has to be supported by current psychology theories. The present work describes a formal model of artificial emotions based on the dimensionality theory, together with simulation results of an initial experimental evaluation. The model includes interesting aspects of emotions, such as emotion changes due to perception, long term affects due to mood, and emotion contagion due to social interactions.