Three Mile island 16.422 Automation worked correctly Confirmation bias: people seek out information to confirm a prior belief and discount information that does not support this belief At TMl, operators selectively filtered out data from other gauges to support their hypothesis that coolant level was too highThree Mile Island 16.422 • Automation worked correctly • Confirmation bias: people seek out information to confirm a prior belief and discount information that does not support this belief – At TMI, operators selectively filtered out data from other gauges to support their hypothesis that coolant level was too high