The document contrasts a fixed mindset, where intelligence and abilities are seen as innate traits that cannot change, versus a growth mindset, where intelligence and abilities are things that can be developed through effort. Those with a fixed mindset believe effort is not important, avoid challenges, and feel threatened by others' success, while those with a growth mindset believe effort is key, embrace challenges, and are inspired by others' achievements. The document advocates adopting a growth mindset for learning and improving.