According toKnowles' Adult Learning Theory(referenced in the Certification Reading List:The Adult Learner, Knowles, 2015), adults "bring rich experiences into the learning environment" and "learn best when those experiences are acknowledged and integrated into the session".
Inviting discussions directly draws upon their prior knowledge, making learning personally meaningful and more effective.
Reference:The Adult Learner, Knowles (2015), Adult Learning Principles.