Stimuli that activate processes needed for effective adult learning, as developed by educational psychologist Robert Gagne. Gagne theorized that both external conditions (stimuli presented and arranged by the trainer) and internal conditions (skills and capabilities the learner has already mastered) are necessary for learning. The nine events of instruction are hierarchical: (1) gain attention, (2) inform learners of objectives, (3) stimulate recall of prior learning, (4) present content (5) provide learning guidance, (6) elicit performance (practice), (7) provide feedback, (8) assess performance, and (9) enhance retention and transfer to the job.