The following diagram illustrates the various ways in which information is preserved in evolution.
On the left we see the cellullar realm. On the right is inheritance via brains. Environmental persistence is at the bottom.
"Dual inheritance" theories deal mostly with information represented in DNA and information that is socially-transmitted. These are the biggest two persistent channels.
On the right hand side, "individual learning" is included. That refers to the subject that B. F. Skinner studied. However, individual learning is a bit of an odd-one-out in this diagram. The reason for that is that individually-learned information does not normally persist for very long - since it dies with the individual. In humans it sometimes turns into socially-transmitted information - thus persisting beyond the death of its host.
Now we get to the point of this post. Individual learning is critical to understanding social learning.
For example, learning to ride a bike is about 10% social learning and 90% individual learning.
When ideas compete for attention inside minds, their origin (from self or other) is not critical - all ideas compete for mental real estate in a similar way.
Individual learning builds on top of socially learned information, and the results are then transmitted to the next generation via social learning again.
These areas of social learning and individual learning are highly interwoven and interdependent.
It is impossible to study the evolution of socially learned behaviours in isolation. Because of their interdependence, the more scientifically significant domain is based on the union of social and individual learning - the study of the evolution of learning systems.
Individual learning too is best modelled using an evolutionary foundation - as was observed by Skinner himself. However, the Darwinian science of thought competition is even further behind than the Darwinian science of meme competition.
I think part of the problem here is the word "culture". The term carves social learning off as though it is an independent thing - when in fact that is a misleading way of thinking about it.