Executive control training reduces rumination.

Rumination (thinking repetitively and passively about negative emotions, focusing on symptoms of distress) is a maladaptive form of self-focus that is a core factor in depression and other disorders of emotion dysregulation. Cohen et al. show that training individuals to exert executive control when processing negative stimuli (to attenuate the effects of emotional content) can alleviate subsequent ruminative thinking and rumination-related sad mood. The training used an arrow version of the flanker task:

In this task, participants indicate the direction of a middle arrow while ignoring two distracting arrows on either side. The distractors are either congruent or incongruent with the direction of the target arrow. Responding to incongruent trials is slower than responding to congruent trials because they present a cognitive conflict and executive control is recruited to resolve this conflict. In each trial, the flanker stimulus is followed by a negative or a neutral picture. The effect of the flanker stimulus type (congruent vs. incongruent) on emotional interference is assessed using a simple discrimination task in which participants are required to indicate whether a square is blue or green. The discrimination task is performed immediately after the presentation of the picture. Our prior work has shown that prolonged RT on the discrimination task following negative compared with neutral pictures was found following congruent but not incongruent stimuli...Participants were assigned either to an experimental group, in which 90% of the negative pictures were preceded by incongruent stimuli, or to a control group, in which only 10% of the negative pictures were preceded by incongruent stimuli. For both groups, the emotional flanker task contained 50% congruent and 50% incongruent stimuli, which were followed by 50% negative and 50% neutral pictures. Thus, the only difference between the groups was the pairing of congruent and incongruent flanker stimuli with negative or neutral pictures. We predicted that compared with participants in the control group, participants in the experimental group (i.e., where 90% of the negative pictures were preceded by incongruent stimuli) would show reduced ruminative thinking and rumination-related negative mood following the training.

Their data show that processing incongruent flanker stimuli prior to the presentation of emotional stimuli (i.e., exercising executive control) can promote inhibition of irrelevant emotional information and reduce its interference. Here is the abstract:

Rumination, a maladaptive self-reflection, is a risk factor for depression, thought to be maintained by executive control deficits that impair ruminators’ ability to ignore emotional information. The current research examined whether training individuals to exert executive control when exposed to negative stimuli can ease rumination. A total of 85 participants were randomly assigned to one of two training conditions. In the experimental condition activation of executive control was followed predominantly by the presentation of negative pictures, whereas in the control condition it was followed predominantly by neutral pictures. As predicted, participants in the experimental group showed reduced state rumination compared with those in the control group. Furthermore, trait rumination, and particularly its maladaptive subtype brooding, was associated with increased sadness only among participants in the control group, and not in the experimental group. We argue that training individuals to exert executive control when processing negative stimuli can alleviate ruminative thinking and rumination-related sad mood.