Support from a TMS/MEP study for a direct link between positive/negative stimuli and approach/avoidance tendencies.

Previous behavioral studies using stimulus-response compatibility tasks have shown that people are faster to carry out instructed approach/avoidance responses to positive/negative stimuli. This result has been taken as evidence that positive/negative stimulus valence directly activates a tendency to approach/avoid, which in turn, facilitates execution of instructed approach/avoidance behavior. In these studies, however, it cannot be excluded that the results reflect a purely semantic link between stimulus valence and instructed responses. According to this alternative interpretation, positive/negative stimuli do not elicit an approach/avoidance tendency, but instead they interact with the positive/negative valence of the instructed responses, and in this way, produce the observed compatibility effect. To circumvent this possible disadvantage of compatibility tasks, we used a novel method for the measurement of early action tendencies: TMS induced MEPs. In two experiments, participants were first trained to abduct the index finger to approach and the thumb to avoid. Then, they observed a series of positive and negative stimuli. Each stimulus was followed by a TMS pulse (at 400 ms post-stimulus onset) and MEPs were measured continuously on the muscles of both fingers. These observation trials were randomly intermixed with response trials, in which neutral stimuli were presented and participants were instructed to approach/avoid the stimuli. In Experiment 1, participants received clear visual feedback on the outcome of their response in the response trials. In Experiment 2, we omitted this feedback to test whether it was necessary for the effect to occur. The results indicated higher MEPs for the approach/avoidance finger after positive/negative stimuli in Experiment 1 but not in Experiment 2. Analyses on the data aggregated over both experiments suggest that the visual feedback was necessary for stimulus valence to elicit action tendencies. Taken together, the results are in line with the results of behavioral studies with compatibility tasks, suggesting that stimulus valence directly elicits specific action tendencies already at 400 ms but they indicate that clear visual feedback is necessary for this effect to occur.

Early Approach and Avoidance Tendencies can be Goal-Directed: Support from a Transcranial Magnetic Stimulation Study.

Dual-process models with a default-interventionist architecture explain early emotional action tendencies by a stimulus-driven process, and they allow goal-directed processes to intervene only in a later stage. An alternative dual-process model with a parallel-competitive architecture developed by Moors, Boddez, and De Houwer (Emotion Review, 9(4), 310-318, 2017), in contrast, explains early emotional action tendencies by a goal-directed process. This model proposes that stimulus-driven and goal-directed processes often operate in parallel and compete with each other, and that if they do compete, the goal-directed process often wins the competition. To examine these predictions, we set up a goal-directed process in an experimental group by rewarding participants for avoiding positive stimuli and for approaching negative stimuli and punishing them for the opposite behavior. We expected this process to compete with a potentially preexisting stimulus-driven process in which positive stimuli are associated with approach and negative stimuli with avoidance. We compared the elicited action tendencies of participants in this group with a control group in which only the stimulus-driven process could operate. Early approach and avoidance tendencies were assessed via motor evoked potentials (MEP) measured in the finger muscles previously trained to approach or to avoid stimuli after single-pulse transcranial magnetic stimulation (TMS) delivered at 400 ms. Results confirmed that positive/negative stimuli led to stronger avoidance/approach tendencies in the experimental group but not to approach/avoidance tendencies in the control group. This suggests that goal-directed processes are indeed able to determine relatively early emotional action tendencies, but it does not show that goal-directed process can defeat stimulus-driven processes.

Demystifying the role of emotion in behaviour: toward a goal-directed account.

The paper sketches the historical development from emotion as a mysterious entity and the source of maladaptive behaviour, to emotion as a collection of ingredients and the source of also adaptive behaviour. We argue, however, that the underlying mechanism proposed to take care of this adaptive behaviour is not entirely up for its task. We outline an alternative view that explains so-called emotional behaviour with the same mechanism as non-emotional behaviour, but that is at the same time more likely to produce adaptive behaviour. The phenomena that were initially seen as requiring a separate emotional mechanism to influence and cause behaviour can also be explained by a goal-directed mechanism provided that more goals and other complexities inherent in the goal-directed process are taken into account.