In considering how mature readers would react to an incident in a narrative, they must consider all previous incidents and the character development of all characters involved in the particular incident. Otherwise the "reaction" tends to be subjective and less critical [in the sense of literary criticism or evaluation] as it should be for mature readers.
Therefore, a key consideration in projecting the reaction of readers to the narrator's treatment of Doodle will consider these factors:
- The narrator mentions early in the narrative that there is in him, as there is in others,
...a knot of cruelty borne by the stream of love, much as our blood sometimes bears the seed of our destruction, and at times I was mean to Doodle.
- He is embarrassed to have a brother like Doodle, so he "set out to teach him." Because of his success in getting Doodle to walk, the narrator believes that he can somehow make Doodle more "normal" by making his brother want to do things.
- In a early incident in which the brother has Doodle in a loft and tries to force him to touch it before picking him up, Doodle cries, "Don't leave me. Don't leave me" after the brother carries him out.
In essence, then, the stage is set for the final incident, and the brother's actions are not out of character. In fact, these actions underscore the prevailing theme of the story that people always suffer when others try to make them over in their own image.
Now, readers may well react emotionally and critically to the act of "cruelty borne by a stream of love" that the narrator commits, they should also understand that in his frustration that Doodle cannot measure up to his standards and be the brother that he desires, the brother's cruelty is unthinking,
The knowledge that Doodle's and my plans had come to naught was bitter, and that streak of cruelty within me awakened.
When, however, the "flood of childish spite evanesced," he then waits for Doodle, thinking his brother will catch up to him and finally runs back to retrieve Doodle. In his rue for his mindless cruelty, the brother weeps for his "fallen scarlet ibis" as well as for himself--he who has been cruel out of a mistaken notion of love.
Readers, then, may well be angry with the narrator, who has, indeed, been spiteful and selfish, but they may also feel pity for him as he must carry the burden of his cruel "stream of love" for the rest of his life.