There is ongoing debate about whether control-related processing related to cognitive conflict and emotional conflict operate independently. This study manipulated the proportion of congruent to incongruent trials to determine the domain specificity or generality of these two types of conflict control. Two experiments were conducted in which spatial Simon conflict was combined with emotional face-word conflict. In Experiment 1, the proportion congruency (PC) of spatial conflict was manipulated, and in Experiment 2, the PC of emotional conflict was manipulated. The aim was to determine whether control-related processes elicited by cognitive or emotional conflict show domain-specific (within cognitive or within emotional control-related effects) or domain-general effects, where control elicited by cognitive conflict benefits emotional control processes and vice versa. Behavioral findings indicated that spatial and emotional conflict exhibited within-domain PC effects. For event-related brain potential (ERP) activity, PC effects were primarily reflected in a late slow potential, rather than an early negativity, suggesting that control-related adjustments impacted conflict resolution rather than conflict detection. Furthermore, the results did not show evidence of PC effects across domains for behavioral or ERP data, indicating that proactive control elicited by PC manipulation does not transfer across cognitive and emotional conflict. This study supports the modular nature of proactive control for processes related to cognitive and emotional control.