Is it helpful for individuals with minor depression to keep smiling? An event-related potentials analysis

We used event-related potentials (ERPs) to explore the influence of manipulating facial expression on error monitoring in individuals. The participants were 11 undergraduate students who had been diagnosed with minor depression (MinD). We recorded error-related negativity (ERN) as the participants performed a modified flanker task in 3 conditions: Duchenne smile, standard smile, and no smile. Behavioral data results showed that, in both the Duchenne smile and standard smile conditions, error rates were significantly lower than in the no-smile condition. The ERP analysis results indicated that, compared to the no-smile condition, both Duchenne and standard smiling facial expressions decreased ERN amplitude, and ERN amplitudes were smallest for those in the Duchenne smile condition. Our findings suggested that even brief smile manipulation may improve long-term negative mood states of people with MinD.