Is ‘Divide and Conquer Algorithm’ a human instinct?

Last Friday I was with my son at a restaurant, I was browsing the menu, when I thought I will give my son a quick problem, and see how far he reaches in solving it. The menu had 5 pages, each page had about 20 items.

I asked my son if he could find the ‘cheapest’ and the ‘costliest’ items in the entire menu.

My son is 6 years old, and does some very basic mathematics at the school, such as arranging numbers in ascending and descending orders, simple single-digit additions and subtractions, etc.

I was amazed to find that, my son quickly found the cheapest item on page #1, then the cheapest item on page #2, chose the lesser of two ( MIN(page#1,page#2) ), and then recursively did that for pages 3, 4 and 5. And gave me the cheapest item on the menu (Rs. 6). He then did the same for costliest item, he found the costliest item on page #1, then the costliest item on page #2, chose the higher of two ( MAX(page#1,page#2) ), and gave the answer (Rs. 95). [We were at a Udipi restaurant, so things are not that costly here.]

I never taught him the ‘divide and conquer algorithm’, in fact I have never taught him any algorithm.

Is ‘Divide and Conquer Algorithm’ a human instinct? Does it come without learning?

Thoughts?