Those studies, which do consistently show significant effects despite your citation-unladen claim, explore averages across a general population and seek to expl

Those studies, which do consistently show significant effects despite your citation-unladen claim, explore averages across a general population and seek to explain society-wide phenomena through the lens of "average" humans. This implies an assumption of homogeneity within the general population. Such tests will of course be underpowered compared to case studies in specific circumstances, particularly those involving self-selection and a cohort-level cultural bias toward "I'm smart and need to pick things up quickly for my day job which means that skill is equally accurate and transferrable to everything I read about".