As the reader might suspect, it is most certainly the Kiowa heritage that causes Momaday's grandmother, Aho, to develop her feelings about the sun. If one wants to be more specific about it, one could say that the Sun Dance in particular helped Aho develop her very religious devotion. Remember how Momaday most often remembers his grandmother:
I see my grandmother in the several postures that were peculiar to her ... praying. I remember her most often at prayer.
Who is Aho praying to? Aho is praying to Tai-me, the Sun Dance god of the Kiowa. She developed these feelings specifically at age seven and age ten when she witnessed two of the most important Sun Dances of the Kiowa tribe of Native Americans.
When Aho was seven, she saw the last complete Sun Dance. The effigy of Tai-me was suspended on the pole in the Sun Dance lodge and the tribe was able to worship Tai-me effectively. In fact, all of the religious rituals were completed at that particular Sun Dance.
Unfortunately, the Sun Dance Aho witnessed when she was ten years old was not complete. The rituals were disturbed and never completed because the soldiers from Fort Sill invaded and dispersed the Kiowa tribe. Regardless, Aho maintained her strong religiosity and passed it down to her grandson, Momaday.