No. But your question seems odd. I didn't interpret the book as an attempt to start with the increase in intelligence and then to assume/explain why pop culture was the cause. Rather, I interpreted the book as an attempt to analyze pop culture, which then found that pop culture did things that seemed like they would have beneficial effects. His analysis of the things that pop culture does in our minds is what I found interesting, not so much the parts which talked about intelligence more generally.

Additionally, I'm not really sure what someone would do to identify pop culture as the cause of this increase as opposed to something else. I'm not sure what other factors could be responsible.