The impact of positive and negative affect on aperiodic EEG activity: evidence for a shared neural basis of metacontrol and emotion

Metacontrol refers to the ability to dynamically adjust cognitive-control strategies, ensuring a balance between persistence and flexibility. Empirical findings point to a strong link between metacontrol and emotion, but the mechanistic underpinnings of this link remain unknown. Here, we had two goals. First, we hypothesized that metacontrol and emotion are mechanistically linked through aperiodic EEG activity, in the sense that both positive emotion and metacontrol flexibility come with increases, and both negative emotion and metacontrol persistence with decreases of aperiodic activity. Second, we tested whether and to what degree emotional stimuli affect behavior and aperiodic activity automatically. In a large sample (n = 120), we examined EEG and behavioral data from three tasks in which we systematically varied the task-relevance of the emotional information presented to participants. As hypothesized, positive pictures resulted in higher aperiodic activity than negative pictures. Task context and, more specifically, the relevance of emotional stimuli significantly influenced overt behavior but had no effect on aperiodic activity. We conclude that positive and negative emotions may represent the phenomenal "feel" of metacontrol biases towards flexibility and persistence, respectively, and that the degree to which processes are affected by emotional content automatically depends on the process under consideration.