A neighbor once told me that he often dresses, ties his shoelaces, drags his toothbrush around, starts the car, drives down the parkway, and arrives at his office without much mental effort; this sometimes alarms him. Yet we all do it. We all have days where we go through the motions like an automaton. How many mornings have I walked to the train station without noticing who I passed along the way?

For this zombie-like state, we can thank the “default mode network,” which is located in the brain’s prefrontal, parietal, and temporal lobes. The theory of the default mode was first studied in the early 2000s by researchers from the Washington University School of Medicine. They found that these brain regions activate when we are not engaged in a specific cognitive task to avoid mental overload and allow our minds to wander.

This default mode protects us from applying brainpower where it isn’t needed; we switch off and go on autopilot. Mundane chores, like sweeping the floor, benefit from this kind of auto-effort, in which the body does all the work and saves the mind from taxing itself. This is also partly because heuristics are at work—these are mental shortcuts that let us make decisions and judgment calls, and solve problems swiftly. The brain doesn’t want to expend too much effort on certain routine tasks, so it uses shortcuts to approach thinking quickly. For example, financial professionals use heuristics to analyze data and make informed decisions about investments. If the earnings of shares of a company dip below a certain number, then financial advisers may recommend taking action.

Many researchers have studied heuristics, but two people to highlight are the late Princeton professor of psychology and Nobel laureate Daniel Kahneman and his late collaborator, cognitive........

© Psychology Today