People tend to seek evidence that fits what they already think

Nickerson's 1998 review defines confirmation bias as looking for or interpreting evidence in ways that favor existing beliefs or the hypothesis you started with. He documents it across many settings. An early demonstration came from Wason in 1960. People trying to discover a hidden rule mostly tested cases they expected to fit, rather than cases that could prove their guess wrong. On Critically, this shows up as a note with many supporting citations and an empty Refutes tab, because nobody looked.