Fig. 1: Incentivized and rest trials for the MID task.
From: Trait anxiety on effort allocation to monetary incentives: a behavioral and high-density EEG study
a Structure of the trial until the participant’s response. Each trial begins with a fixation cross followed by the appearance, alongside the fixation cross, of the incentive stimuli (CHF 1, 0.5, or 0.2) or a blurred coin face indicating a rest trial. The stimulus stays on-screen for an anticipatory period of 3.5 s, after which, a red circle appears around the fixation cross prompting the participant to act (except for rest trials) by squeezing the clench. The incentive remains on screen until the end of the trial and feedback about the participant’s response is given, using the color of the circle and fixation cross. b Possible outcomes for the participant’s response. Line colors represent the color of the enclosing circle and arrowheads point toward moments when feedback is given. Once the response is prompted, the circle remains red and participants have 2 s to reach the threshold of 40% MVC. If this is accomplished before 2 s, the circle turns green. Otherwise, a red cross replaces the fixation cross, indicating the failure of the trial. During the 3 s of the maintenance period, the circle remains green unless the exerted grip force drops below the maintenance threshold of 40% MVC—5 kgf, which results in the appearance of a red cross surrounded by a red circle signaling trial failure. If the maintenance period is completed above its threshold, the trial is successful and a green checkmark appears in place of the fixation cross during 1 s
