Those of you familiar with old school theories of game may know the Survival and Replication theory of attraction. Essentially, humans are machines whose goal is to survive and reproduce. People are attracted to things that offer survival and replication benefit to them. Men are attracted to healthy young females that can bear healthy offspring i.e. primarily replication value. Women are attracted to men that can provide good genes, protection, and resources for child rearing. What turns men on is fairly simple to understand. Women are turned on by a more complex mix of factors, however, these factors can be understood as relating back to the promise of survival or replication value.

Among many other things, women are attracted to fun dudes that bring positive emotions to the interaction. How would you relate fun to survival/replication value? Is fun inherently valuable or is fun a proxy indirectly conveying other valuable survival/replication traits? What is the S&R value of being fun?