function of introduction

1. only the context necessary for your research question
2. only reliable sources, and probably only Berridge (2016)
3. context out of which your RQ emerges, back and fourth, some sort of discussion, "they say," "these other people say," etc. sense of the conversation and how the RG emerges out or or fits into the conversation 
4. gap
5. RQ that speaks to or tries to fill gap