The phrase "different backgrounds" means that people come from various cultures, experiences, or lives, which can influence their perspectives and ways of thinking. Full definition
Birth parents and adoptive parents often come from different backgrounds with different life experiences with varying degrees of «power» in the relationship. (creatingafamily.org)
Instruction should take into account the wide range of different backgrounds of learners; learning materials and activities should allow for different levels / types of previous experience with computers. (elearningindustry.com)
This is not only because people with different backgrounds bring new information. (scientificamerican.com)