Justice norms cover the fairness of decisions regarding the allocation of resources.
Allocation of resources regarded as unfair elicit anger in those who believe they have been unjustly treated (Sanfey et al. 2003). Considerable work has examined justice reasoning in the context of cooperation tasks (e.g., the Ultimatum and Trust games). In such games, a proposer suggests an allocation of resources and typically the participant decides whether or not to accept this allocation or punish the proposer for the unfairness of his offer (de Quervain et al. 2004; King-Casas et al. 2008). The greater the difference in the allocation of resources between the individuals, the greater the sense of the unfairness of the offer and the greater the amount that the participant is prepared to pay in order to punish the proposer (e.g. White et al. 2013).
Unfair offers by proposers have been found to elicit activity in participants within both the anterior insula cortex (AIC) and the dorsomedial frontal cortex (DMFC); King-Casas et al. 2008; Rilling et al. 2002; Sanfey et al. 2003; White et al. 2013). There have been suggestions that activity within these regions reflects anger elicited by unfariness to the self (Sanfey et al. 2003). This is consistent with the argument raised above that these regions respond to anger or expectations of anger (including in response to norm violations) and organize changes in behavior (Blair and Cipolotti 2000).
In short, unfair offers make individuals angry and activate regions of the DMFC and AIC/IFG implicated in responding to anger and organizing behavior on the basis of this anger.
R. J. R. Blair, Soonjo Hwang, Stuart F. White, Harma Meffert
(Emotional Learning, Psychopathy, and Norm Development în Moral Brains: The Neuroscience of Morality (coord. S. Matthew Liao), Oxford University Press,2016, la p. 194)