Fung, M.-C. and Jackson, C. 2024. When feeling positive is being “in the zone”: How challenge optimality causes changes in positive affect and flow. Cyberpsychology: Journal of Psychosocial Research on Cyberspace. 18, 4 (Sep. 2024), Article 7. DOI:https://doi.org/10.5817/CP2024-4-7.