I found a very interesting website with a method of demonstrating private biases that I found to be interesting, and is said to be very accurate
https://implicit.harvard.edu/implicit/demo/
I took the test on race and found that I have a strong bias towards european americans over african americans, which really surprised me, but I can see where it comes from. As much as I try to deny that it has affected me, it I do come from a racist background.
What about you, do you have any secret biases that you try to overcome or hide?