“…In the 21st century, the literature showed the various aspects of informal learning had been involved in the range of extensive and in-depth academic discussions. Regarding to the subjects of informal learning, the pilot studies focused on students and teachers, including K-12 and university students [28], [29], [30]; new and experienced teachers [31], [32], [33], [34]; doctors and nurses [35], [36]; and other diverse types of workplace informal learning in every industries, such as trade unions, investment bank, and other informal cooperative learning environment [37], [38], [39].…”