What combination of characteristics defines something as either childish or for adults? Simplicity? Theme? Duration? Limited choices? Limited depth?
When a kid beats you at Concentration, the action choices are limited, but the actual number of items available to choose can be pretty extensive. What about when a kid beats you at chess? Is he or she a super genius, or did his or her parents simply believe in, and invest time in teaching, him or her more than yours did? Does that make chess "for kids"? Or for all ages?
Do kids win by strategic thinking or by pattern recognition? What about adults?
What makes something "for kids" in one country while in another country it falls within the purview of adults, such as anime or video games?
No post yet, just thinking out loud ...