What does The truth is that most of what we learned about dog's vision growing up is based on misconceptions. mean?

I am confused about the 1st line.
If it said "The truth is that most of what learned about dog's vision is based on misconceptions", I would understand it.
But it says "what we learned about dog's vision growing up".....


The truth is that most of what we learned about dog's vision growing up is based on misconceptions. You might want to sit down for this shocker: Dogs are not, in fact, colorblind.

Crazy, right? The next thing you know, someone will debunk the theory that eating carrots makes you see better. Wait, what do you mean that isn't true either? My life is a lie. The silver lining, though, is the happy news that dogs don't actually have to go through life in black and white.