Problem solving, completing set tasks, following complex story lines are skills that can be learnt from pop culture. Johnson argues that popular culture has, on average, grown more complex and intellectually challenging over the past thirty years and this has led to smarter individuals. At no point does Johnson claim that pop culture is better than traditional culture, just that pop culture should not be viewed as rubbish.
This book is very readable and I must say I enjoy the examples Johnson uses to illustrate his points. Well worth reading.