How does fear shape our decisions & actions? How is the narrator of “Ibis” motivated by fear?

Fear is one of our most basic emotions. Somewhere in our collective primordial brain it is fear that dictates our actions in order to survive. The narrator has Doodle's best intentions in mind, but he allows his pride and determination to get in the way, which ultimately results in tragedy. I suppose fear of failure in both the narrator and doodle drives them to go to extremes. I think expectations and fear of not reaching them is more appropriate. For Doodle surpassing expectations means his brother's affection. For the narrator surpassing expectations has more to do with personal validation than anything else.