Once upon a time, retail stores had employees who were not cashiers but roamed the floor, assisting customers. Go into a Wal-Mart or Target or Staples and find someone to help you locate and choose a product. Good luck. You’re on your own, left to wander the aisles in search of an unoccupied staff person. (Meanwhile, you might stumble on and purchase some item you hadn’t planned on buying.) Here, it’s not technology, but a business tactic that cuts payroll expenses by trimming the service provided to customers — and prolongs the time those customers spend rambling around inside the store. Regardless, the result is still more shadow work, as customers take on the job that retail salespeople once did.

Shadow work isn’t always unpaid; sometimes it shows up at one’s salaried job in the form of new tasks covertly added to one’s responsibilities. Not long ago, human resources departments kept track of employees’ vacation, personal and sick days. In many organizations, employees now enter their own data into absence management software.

One nostalgic appeal of the “Mad Men” television series is the way it evokes memories of certain amusingly dated aspects of business life, like “support staff,” and even “secretaries.” Support staff is becoming a quaint, antiquarian concept, a historical curiosity like typewriters, stenography and executive washrooms. We all have our own computers, of course, and we type and print our own letters, copy our own reports and mail our own missives. Even those in senior management perform these humdrum jobs.

Of course, these shadow chores never appear in one’s job description, let alone justify any salary increase. Shadow work is just covertly added to our daily duties. As robotic devices replace human workers, end-users like customers and employees are taking on the remnant of the transaction that still requires wetware — a brain. New waves of technology change how things are done, and we docilely adapt — unavoidably so, as there’s usually no alternative. Running a business without e-mail is hardly a viable option, but with e-mail comes spam to be evaluated and deleted — more shadow work.

TO be sure, shadow work has its benefits. Bagging one’s own groceries or pumping one’s own gas can save time. Shadow work can increase autonomy and enlarge our repertoire of skills and knowledge. Research on the “Ikea effect,” named for the Swedish furniture manufacturer whose products often require home assembly, indicates that customers value a product more highly when they play a role in constructing it.

Still, doctors routinely observe that one of the most common complaints today is fatigue; a 2007 study pegged its prevalence in the American work force at 38 percent. This should not be surprising. Much of this fatigue may result from the steady, surreptitious accumulation of shadow work in modern life. People are simply doing a huge number of tasks that were once done for them by others.

Doing things for one another is, in fact, an essential characteristic of a human community. Various mundane jobs were once spread around among us, and performing such small services for one another was even an aspect of civility. Those days are over. The robots are in charge now, pushing a thousand routine tasks onto each of our backs.