Distraction-conflict theory contends that when a person is working in the presence of other people, an interference effect occurs splitting the individual's attention between the task and the other person. On simple tasks, where the individual is not challenged by the task, the interference effect is negligible and performance, therefore, is facilitated. On more complex tasks, where drive is not strong enough to effectively compete against the effects of distraction, there is no performance gain. The Stroop task (Stroop effect) demonstrated that, by narrowing a person's focus of attention on certain tasks, distractions can improve performance.