There is nothing surprising about BlackRock's decision to begin replacing human portfolio managers with artificial intelligences, at least not to anyone who has been following the financial industry. And unless you are one of the dozens of human portfolio managers whose jobs are being replaced by AIs, there is nothing wrong with it either -- as long as BlackRock remembers what happened to Knight Capital. In 2012, Knight Capital almost went bankrupt after its new automated trading algorithm made $440 million in bad trades in just 45 minutes. The Knight Capital story is a cautionary tale about what can happen when companies defer too much of their decision making to automated systems, and a textbook example of what cognitive psychologists call automation bias. Automation bias refers to our tendency to stop questioning the results generated by such automated systems once we begin to rely on them.