According to RG Help Center page, RG Score is relative, it can go up or down depending on the activity and scores of other ResearchGate members. This means it takes the scores and interactions of every researcher into account to give a relative rating of your contributions. Next, to improve your RG Score:
Share anything from negative results to raw data or full-fledged publications
Create a project, or add an update to your existing project(s)
Ask a question or give another researcher a helpful answer
Follow other researchers
Comment on and recommend your peer's research, projects, and questions