In new research, Cailtin K. Myers and Ezekiel Hooper find that birth rates in the United States have declined as a result of the introduction of the iPhone. They theorize that the smartphone is crowding out the market for attention, offering a device to fill users’ time that replaces forming in-person relationships that typically create children.
Disentangling a slow cultural shift from the discrete events that reshape it is hard, which is what makes the American fertility decline such a puzzle. But consider the timing. The general fertility rate in the United States began its long fall in 2007, the same year Steve Jobs walked onstage and introduced the iPhone as an iPod, a phone, and an internet communicator in one device: the first smartphone. The most consequential thing to happen to American birth rates this century, on the evidence my co-author and I have assembled, was not a contraceptive, a recession, or a subsidy. It was a phone. And the only reason we can say that with any confidence is that Apple sold it, for its first four years, under a monopoly.
From the iPhone’s launch in June 2007 until February 2011, Apple distributed it in the U.S. through a single carrier, AT&T. Whether you could own a working smartphone—the iPhone—depended on something close to arbitrary: whether AT&T’s cellular network happened to reach your county. Some places had near-total AT&T coverage. Others had almost none. That gap was created by a distribution monopoly, not by anything about the people living on either side of it, which is exactly what makes it useful. It splits the country into two groups that differ in iPhone access for reasons unrelated to who they are.
Since 2007, the U.S. birth rate among teenagers has fallen about 70 percent, a drop no policy intervention ever came close to producing, and it isn’t only teens; rates have fallen at every age through the early thirties, leaving overall fertility at the lowest level on record. The 2007 Great Recession was the early suspect, but the recession ended and births kept falling. Contraception and abortion access shifted too little, and on the wrong timeline, to account for a move this large. Childcare and housing costs might explain why a 32-year-old postpones a planned child, but much of the decline is in unintended births among the young, where the cost of raising a child wasn’t the main contributing factor. After working through the usual explanations and rejecting them, economists Melissa Kearney and Phillip Levine concluded that the field should stop forcing the decline into a conventional economic frame and start looking for broader forces, driven partly by a widening menu of things to do other than raise children: digital media, gaming, online pornography, and social networks.
Psychologists have offered a less deliberate version of the same idea. For over a decade, Jean Twenge and Jonathan Haidt have argued that the smartphone rewired a generation: less time together, less dating, less sex, not because anyone chose to want those things less but because the device crowded them out. The timing is suggestive: American teenagers went from roughly 141 minutes a day with friends in person in 2003 to about 43 by 2024. It is hard to accidentally become a parent in a room you are not in. But suggestive is all it has been. “It’s the smartphones” being the theory in search of a test.
That is what the AT&T monopoly lets us run. We compared counties with near-universal AT&T coverage to counties with almost none, tracking age-specific birth rates year by year as the iPhone spread through the first group and barely reached the second. The pattern is stark: places that looked alike before 2007 diverged sharply after it, and only in the direction of iPhone access. After trying a battery of statistical methods meant to break the result, it holds. We estimate that access to the iPhone reduced births by 4.5-8 percent among women aged 15-19 and 3.2-6.6 percent among those aged 20-24, with smaller but still meaningful declines at older ages. Scaled up, those effects imply the iPhone explains somewhere between a third and a half of the entire decline in fertility from 2007-2011.
There is the obvious objection: maybe this is just the result of good cellular coverage, not the iPhone. So we ran the same design on Verizon and Sprint, which had strong networks in those years but no iPhone, and no smartphone of any kind until Android arrived in late 2009. During the exclusive smartphone years for AT&T, their coverage did nothing to births. And then, once those carriers got smartphones, births in their coverage areas began to fall too. Connectivity alone did nothing. The smartphone did. That is the strongest evidence yet that smartphones are not merely correlated with the birth collapse but are a meaningful cause of it.
A caution I’d extend to myself as much as to any reader: our design proves the iPhone moved births, not exactly how. The collapse in face-to-face time, the rise in pornography, and the fall in partnered sex are real national trends, but we cannot tie them county-by-county to AT&T’s map the way we can tie births. What the causal evidence does pin down is where the effect lands, on the young and on unintended births, and that is the fact the policy conversation should turn on.
What I suspect is going on, though I want to be clear this is interpretation and not something our county data can prove, is a quieter kind of crowding out. The phone in your pocket is not a neutral tool you pick up and put down. It is engineered to hold your attention, because attention is the thing being sold, and it competes for that attention every waking minute against everything else you might do, including the slow, awkward, in-person interaction of meeting someone. Finding a partner has always been inefficient. It takes unstructured time, proximity, a tolerance for boredom and risks. A device optimized to fill exactly that unstructured time with something more immediately rewarding doesn’t have to make anyone decide against relationships. It just has to make the alternative a little easier, a few hundred times a day, until the opportunities to form a relationship quietly thin out. The fertility decline, on this reading, is downstream of an attention economy that got very good at occupying the hours in which people used to find each other.
Our results suggest why many incentives by governments on increasing fertility are frequently falling short. The binding constraint may not be the cost of the child at all. It may be upstream, in whether the relationships and the in-person time that produce children, planned or not, are forming in the first place. If that’s right, then cash transfers, tax credits, and subsidized childcare are aimed at a margin that has stopped being the one that matters, however sensible they look on a spreadsheet. After centuries of trying and failing to regulate young people’s sexual behavior through law and exhortation, a consumer product did it by accident. The lesson for anyone hoping to reverse the trend is not that we found the lever. It’s that the lever almost everyone is pulling may not be connected to anything.
Authors’ Disclosures: The authors report no conflicts of interest. Hooper works in consulting (Accenture) but his research is not a reflection of the firm. You can read our disclosure policy here.
Articles represent the opinions of their writers, not necessarily those of the University of Chicago, the Booth School of Business, or its faculty.
Subscribe here for ProMarket’s weekly newsletter, Special Interest, to stay up to date on ProMarket’s coverage of the political economy and other content from the Stigler Center.
