Gamification and other types of difficulty scaffolding methods have become very popular in educational settings, whereby the learning process is divided into smaller pieces that present students with optimal challenges for their skills and increase demands incrementally. These methods aim at increasing students' motivation and task engagement, since too difficult tasks tend to be frustrating, too easy tasks may quickly become boring, and tasks that were optimally challenging yesterday may be mastered and become boring today. However, these ideas have also been criticized under the argument that teachers are making it too easy for students, and hence, students have the feeling that they are succeeding while leaving aside relevant learning outcomes.

We investigated the challenges and benefits of task difficulty on performance, emotional state, and motivation, as well as the effects on event-related brain potentials associated with confidence about own performance. Seventy young adults completed a random motion task with three levels of difficulty (easy, moderate, hard). We tested the hypothesis that moderate difficulty, considered as optimal level, would have positive effects in mood state and task engagement, as it would be challenging but achievable. We also tested possible moderation of the effects by big-five personality traits (e.g., conscientiousness, openness) and self-regulation (i.e., learning from errors, perseverance). Contrary to our hypothesis, linear mixed models showed linear trends in almost all measures, revealing a benefit in mood and engagement for easy rather than for moderate (and -of course- rather than difficult) tasks. Differential analyses revealed that students scoring high in openness showed overall greater engagement in the task. Interestingly, we also observed a moderation by trait perseverance in the amplitude of a long lasting centro-parietal positivity reflecting confidence about own performance. Namely, students who tend to persevere more seem to have greater confidence in their own responses, when the task is of easy to moderate difficulty. We will discuss implications of the findings for education, for example, teachers using techniques such as gamification should find an optimal balance between making learning tasks easy and gamified, and at the same time upholding the relevance and robustness of learning outcomes.

Keywords: Emotion, Engagement, Big-five, Self-regulation, ERPs, Confidence, Young-adults, Education, Random dots motion, Perseverance.