In my case experts are people who raised well adjusted children and are still happily married! It can even be your own parents as much as people (very prideful) don’t want to admit that.

My parents read child psychology and based on that changed their mind on whether spankings were something good for your kids.

They updated their views based on expert peer-reviewed evidence instead of relying on their own armchair theories. I laud them for that. I used to be pro-spanking since I turned out OK and was stunned to later learn my parents regretted it all after what they subsequently learnt. They earnestly wish they had learnt sooner it wasn't necessary.