Here, though, we must be careful not to confuse jobs or occupations with tasks. What a particular occupation “does” is never one thing. A job is only ever a specific grouping of discrete tasks, some of which are more repetitive and easily mimicked by machines, others of which are more intuitive, subjective, contingent. Automation replaces tasks, not jobs. When the principles of automation are introduced into a particular branch of production, this tends to compel a restructuring of the prevailing division of labor rather than simply suppressing this or that “occupation.” The fate of the bank teller is a well-known example. The introduction of the now-ubiquitous automated teller machine (atm) did not spell the disappearance of the human teller; it merely shifted the responsibilities of those employees dealing directly with customers away from handling deposits and withdrawals and toward (say) the marketing of credit cards, consumer loans, and other banking services. The atm, in turn, represents a highly visible example of what Jonathan Gershuny identifies as the rise of a “self-service” economy, in which tasks formerly performed by paid employees are imposed on consumers: the automated teller replaces the bank employee’s labor not with a machine, but with the free labor of its user.

The bottom tier of the job market made up in large part of service occupations is resistant to wholesale automation because labor-saving innovation is happening elsewhere in the economy: labor-process refinements in other sectors shed workers who, because they must work to live, are shunted into low-wage, low-skill occupations. This surfeit of available labor creates intense competition for otherwise undesirable jobs, holding wages down. There can be an oversupply of labor in this sector, though, because these jobs are deemed to require little to no pre-existing skill, requiring no special training or aptitude to perform the tasks associated with them. In many cases, workers who hold these positions are trained on the job, or at most subject to short introductory training sessions or programs before they begin.