Most of us want to believe that automation frees us to spend our time on higher pursuits but doesn’t otherwise alter the way we behave or think. That view is a fallacy—an expression of what scholars of automation call the “substitution myth.” A labor-saving device doesn’t just provide a substitute for some isolated component of a job or other activity. It alters the character of the entire task, including the roles, attitudes, and skills of the people taking part. As Parasuraman and a colleague explained in a 2010 journal article, “Automation does not simply supplant human activity but rather changes it, often in ways unintended and unanticipated by the designers of automation.”

Psychologists have found that when we work with computers, we often fall victim to two cognitive ailments—complacency and bias—that can undercut our performance and lead to mistakes. Automation complacency occurs when a computer lulls us into a false sense of security. Confident that the machine will work flawlessly and handle any problem that crops up, we allow our attention to drift. We become disengaged from our work, and our awareness of what’s going on around us fades. Automation bias occurs when we place too much faith in the accuracy of the information coming through our monitors. Our trust in the software becomes so strong that we ignore or discount other information sources, including our own eyes and ears. When a computer provides incorrect or insufficient data, we remain oblivious to the error.

Examples of complacency and bias have been well documented in high-risk situations—on flight decks and battlefields, in factory control rooms—but recent studies suggest that the problems can bedevil anyone working with a computer. Many radiologists today use analytical software to highlight suspicious areas on mammograms. Usually, the highlights aid in the discovery of disease. But they can also have the opposite effect. Biased by the software’s suggestions, radiologists may give cursory attention to the areas of an image that haven’t been highlighted, sometimes overlooking an early-stage tumor. Most of us have experienced complacency when at a computer. In using e-mail or word-processing software, we become less proficient proofreaders when we know that a spell-checker is at work.

The way computers can weaken awareness and attentiveness points to a deeper problem. Automation turns us from actors into observers. Instead of manipulating the yoke, we watch the screen. That shift may make our lives easier, but it can also inhibit the development of expertise. Since the late 1970s, psychologists have been documenting a phenomenon called the “generation effect.” It was first observed in studies of vocabulary, which revealed that people remember words much better when they actively call them to mind—when they generate them—than when they simply read them. The effect, it has since become clear, influences learning in many different circumstances. When you engage actively in a task, you set off intricate mental processes that allow you to retain more knowledge. You learn more and remember more. When you repeat the same task over a long period, your brain constructs specialized neural circuits dedicated to the activity. It assembles a rich store of information and organizes that knowledge in a way that allows you to tap into it instantaneously. Whether it’s Serena Williams on a tennis court or Magnus Carlsen at a chessboard, an expert can spot patterns, evaluate signals, and react to changing circumstances with speed and precision that can seem uncanny. What looks like instinct is hard-won skill, skill that requires exactly the kind of struggle that modern software seeks to alleviate.

In 2005, Christof van Nimwegen, a cognitive psychologist in the Netherlands, began an investigation into software’s effects on the development of know-how. He recruited two sets of people to play a computer game based on a classic logic puzzle called Missionaries and Cannibals. To complete the puzzle, a player has to transport five missionaries and five cannibals (or, in van Nimwegen’s version, five yellow balls and five blue ones) across a river, using a boat that can accommodate no more than three passengers at a time. The tricky part is that cannibals must never outnumber missionaries, either in the boat or on the riverbanks. One of van Nimwegen’s groups worked on the puzzle using software that provided step-by-step guidance, highlighting which moves were permissible and which weren’t. The other group used a rudimentary program that offered no assistance.