Jacques-Hamilton · Journal of experimental psychology. General 2019 · randomized controlled trial · n=147

Costs and benefits of acting extraverted: A randomized controlled trial.

Level 2 - randomized trial

Individual randomized controlled trial

PubMed 30489119 · doi:10.1037/xge0000516 · record verified 2026-08-26

What was done

Participants (n = 147) were randomly assigned to an "act-extraverted" intervention (acting bold, agentic) or a sham active control intervention for 1 week in everyday life. Data from a contact control condition (n = 76) were also obtained from a previous study. Investigators assessed positive affect, negative affect, feelings of authenticity, and tiredness both in the moment and retrospectively.

What was found

The abstract reports no numerical values or effect sizes. Overall, the intervention showed a positive effect on positive affect and authenticity. However, outcomes depended on baseline disposition: more introverted participants had weaker positive affect increases, experienced increased negative affect and tiredness, and had decreased feelings of authenticity.

Why it matters

This study shows that interventions prescribing extraverted behavior to enhance wellbeing are not universally beneficial, and that acting against one's disposition can carry measurable emotional and energetic costs for introverts.

Limits

The abstract reports no exact numbers, effect sizes, or confidence intervals. The intervention lasted only 1 week, the sample size was modest, and one comparator group relied on historical data from an earlier study. Population characteristics are not detailed.

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