https://www.verywellmind.com/differences-between-extrinsic-and-intrinsic-motivation-2795384. https://courses.lumenlearning.com/teachereducationx92x1/chapter/incentive-theory-of-motivation-and-intrinsic-vs-extrinsic-motivation/. https://www.climbing.com/.amp/news/alex-honnold-completes-first-free-solo-of-el-capitan/#referrer=https://www.google.com theres a source we could use