The Importance of Imagination: A Mechanism for Survival

I found this short story, told in a first-person narrative, to have the same sad undertone as the other stories but also a strong sense of hope.  I noticed, particularly when talking about food, that imagination is the best mechanism for survival.  The narrator notes: "My sister saved up a few quarters and bought food coloring.  For weeks we ate red potatoes, green potatoes, blue potatoes" (151).  This seems like a futile attempt to add variety into their diets.  They talk about different food as if it fuels their imagination: "We imagined oranges, Pepsi-Cola, chocolate, deer jerky" (151).  It seems to me that this food fuels hope at the reservation.