I am looking for the motif in this articlle.

I am looking for the motif in this articlle. I was thinking it was something to do with Nature versus Nurture, or the number 4 as it is mentioned several times and then the story ends with three phone calls, so the motif changing at that point. But I am just unsure exactly what it is in this story.

https://www.newyorker.com/magazine/1948/05/15/symbols-and-signs