As we still try to grapple with the two extreme views of AI making humans redundant and AI making humans super productive, here’s a lesson from history that can help us think about the former (substitution) and the latter (complementarity). David Oks takes the bank teller’s job and shows how the first technology – ATM (Automated Teller Machines) actually made the bank teller’s job more productive until mobile banking made the bank branch and hence its teller totally irrelevant.
When Citibank introduced ATMs at scale in the 70’s:
“…the advantages of the ATM over the human teller were obvious. Running an ATM was cheaper than paying a human—each ATM transaction cost the bank just 27 cents, compared to $1.07 for a human teller—and this could either be passed to the consumer in the form of lower fees or simply kept as profit. And ATMs were also just more convenient. An ATM could do in 30 seconds what would take a human teller at least a few minutes; and while a human teller was only available during business hours, ATMs could be used at any time of day.”
But it didn’t replace the human teller as one would think:
“The number of ATMs per capita grew dramatically after 1975; but the number of bank tellers increased along with it. Bank tellers did become a smaller share of total employment, since the increase in bank teller employment was smaller than the increase in other occupations; but at no point in the period between 1970 and 2010 did the number of bank tellers actually enter a prolonged decline.”
What explains this? The author refers to a paper by David Autor who says:
“First, by reducing the cost of operating a bank branch, ATMs indirectly increased the demand for tellers: the number of tellers per branch fell by more than a third between 1988 and 2004, but the number of urban bank branches (also encouraged by a wave of bank deregulation allowing more branches) rose by more than 40 percent. Second, as the routine cash-handling tasks of bank tellers receded, information technology also enabled a broader range of bank personnel to become involved in “relationship banking.” Increasingly, banks recognized the value of tellers enabled by information technology, not primarily as checkout clerks, but as salespersons, forging relationships with customers and introducing them to additional bank services like credit cards, loans, and investment products.
We thus have a classic case of the Jevons effect. Teller labor was an input into an output that we can call “financial services.” ATMs allowed us to produce that output more efficiently and economize on the use of the labor input. But demand for the output was sufficiently elastic that more efficient production meant more demand: and demand increased to the point that there was actually greater demand for the labor input as well. And—this part is not quite the classic Jevons effect—the greater demand suggested to banks that there had been certain functions that were previously considered incidental to the teller job, like “relationship banking,” which were actually quite useful. And so ATMs were a truly complementary technology for the bank teller.””
Then mobile banking took off with the advent of the iPhone:
“Visits to bank branches declined dramatically throughout the 2010s, and banks aggressively redesigned the banking experience around the digital interface. The number of commercial bank branches per capita peaked in 2009 and has fallen by nearly 30 percent since, with most of the decline occurring in wealthier areas that were more likely to adopt digital banking first. Between 2008 and 2025, Bank of America, which at some point surpassed Citibank as the second-largest deposit bank in the United States after Chase, closed about 40 percent of its branches. Online banking had been around since the 1990s, Bank of America’s CEO said, but the iPhone was a “game changer” that “effectively allowed customers to carry a bank branch in their pockets.”
And as the branch disappeared, so did the teller. ATM had been an innovation within the existing world of physical banking, and thus its replacement of the bank teller could inevitably only be partial; as long as people were still visiting the bank branch, it was useful to repurpose tellers as “relationship bankers.” But when branch visits declined that stopped making sense. The iPhone represented a wholly different way of banking, and within it there was no real need for the bank teller: and so a large institution like Bank of America was able to reduce its headcount from 288,000 in 2010 to 204,000 in 2018.”
What can we learn from this experience about which jobs of today will face a productivity boost from AI and which ones will become irrelevant:
“The ATM tried to do the teller’s job better, faster, cheaper; it tried to fit capital into a labor-shaped hole; but the iPhone made the teller’s job irrelevant. One automated tasks within an existing paradigm, and the other created a new paradigm in which those tasks simply didn’t need to exist at all. And it is paradigm replacement, not task automation, that actually displaces workers—and, conversely, unlocks the latent productivity within any technology. That’s because as long as the old paradigm persists, there will be labor-shaped holes in which capital substitution will encounter constant frictions and bottlenecks.”
And the author reckons that with AI: “We are still very much in the regime of slotting it in. And as long as we are in that regime, I expect disappointing productivity gains and relatively little real displacement.
The real productivity gains from AI—and the real threat of labor displacement—will come not from the “drop-in remote worker,” but from something like Dwarkesh Patel’s vision of the fully-automated firm. At some point in the life of every technology, old workflows are replaced by new ones, and we discover the paradigms in which the full productive force of a technology can best be expressed. In the past this has simply been a fact of managerial turnover or depreciation cycles. But with AI it will likely be the sheer power of the technology itself, which really is wholly unlike anything that has come before, and unlike electricity or the steam engine will eventually be able to build the structures that harness its powers by itself.”
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