Increasingly dependent on habit? A study on the electrophysiological mechanisms of goal-directed and habitual control in internet gaming disorder

Abstract

Background: Public health issues arising from excessive online gaming have garnered significant research interest. Existing studies indicate that, within the framework of the dual-systems theory, the equilibrium between the goal-directed and habitual control systems is disrupted in patients with Internet gaming disorder (IGD). Nevertheless, the understanding of how this imbalance manifests within the brain is limited. This study aims to investigate real-time brain activity in individuals with IGD during the activation of both the goal-directed and habitual systems using electrophysiological techniques.

Methods: Twenty-four individuals with IGD and twenty-three matched recreational game users (RGUs) underwent electroencephalography (EEG) data collection while completing an outcome devaluation task. Differences between the two groups at the Fz, Cz, and Pz electrodes were compared using repeated measures ANOVA.

Results: The behavioral results revealed that the RGU group exhibited higher accuracy than the IGD group during the learning phase (t(45) = -3.08, p < 0.001, η2 = 0.42). During the slip-of-action test, the IGD group made more action-slip responses for devalued outcomes than the RGU group (F(1,45) = 6.22, p = 0.016, η2 = 0.12). The EEG experiment results indicated that, upon stimulus presentation during the slip-of-action test, the IGD group had significantly more negative average amplitudes at the Fz and Cz electrodes compared with the RGUs (-7.26 ± 6.28 μV; -5.18 ± 5.49 μV; F(1,40) = 5.54, p = 0.024, η2 = 0.12; F(1,40) = 4.92, p = 0.032, η2 = 0.11). Concurrently, the single-group analysis based on RGU revealed that habitual control appears to be associated with greater N2 and P3 amplitudes during the stimulus-locked phase.

Conclusions: The goal-directed system of individuals with IGD is impaired, manifesting in the increased cognitive resources required to activate the goal-directed system when they need to disrupt habitual responses. This suggests that the imbalance due to IGD within the dual systems may originate from an impaired goal-directed system rather than the overactivation of the habitual system.

Keywords: electroencephalography; goal–directed; habitual; instrumental learning; internet gaming disorder.

Fig. 1.

The outcome devaluation task. The figure shows the process of the outcome devaluation task, which was developed to differentiate between goal–directed control and habitual learning. (A) During the instrumental learning phase, participants learn stimulus–response–outcome associations, which is stimulated by reward points. (B) In the behavioral test of action-outcome learning, one of the two displayed outcomes is devalued (indicated by a red cross in the image). The participants are instructed to respond with the correct response that is associated with the outcome. (C) In the slips-of-action test, all outcomes are displayed to the participants. Two of the outcomes are devalued. After outcome presentation, the stimuli appear one by one on the screen. Participants are required to respond with the correct learning response, unless the outcomes related to the stimulus are devalued. At this point, participants with strong habitual tendencies will automatically respond to stimuli with learned responses, regardless of the value of the relevant outcomes. IGD: Internet gaming disorder; RGU: recreational game user

Fig. 2.

Stimulus-locked ERPs during the slips-of-action test between IGD (black line) and RGU (red line). ERPs at Fz, Cz and Pz time-locked to stimuli preceding responses to valuable outcomes preceding slips of action and preceding inhibitions to devalued outcomes. Topographies depict the differences between stimuli preceding inhibitions to devalued at the indicated time windows

Fig. 3.

Stimulus-locked ERPs during the slips-of-action test. ERPs at Fz, Cz and Pz time-locked to stimuli preceding slips of action (black line) and preceding inhibitions to devalued outcomes (red line). Topographies depict the differences between stimuli preceding inhibitions to devalued and slips of action at the indicated time windows

Fig. 4.

Response-locked ERPs during the slips-of-action test. ERPs at Fz, Cz and Pz time-locked to responses to valuable outcomes (black line) and slips of action (red line). Topographies depict the differences between slips of action and responses to valuable outcomes at the indicated time windows

Fig. 5.

The correlation between various variables. DSM-5: IGD Diagnostic scale from Diagnostic and Statistical manual of Mental Disorders-5; IAT: Internet addiction test; SPAN: Working memory span; OCI: Degree of obsessive-compulsive disorder; EX1: Correct response of the last block in instrumental learning phase; EX2:Correct response during the action-outcome test; Fz-N2: The N2 mean amplitude at the Fz accompanied by the inhibition to the devalued outcome; Cz-N2: The N2 mean amplitude at the Cz accompanied by the inhibition to the devalued outcome. *p < 0.05, **p < 0.01, ***p < 0.001