In november 1975, one year before the obscure Georgia governor Jimmy Carter was elected president, the field of Democratic presidential aspirants was in chaos. According to the polls, voters’ top choices were Senator Ted Kennedy of Massachusetts (23 percent), Governor George Wallace of Alabama (19 percent), and former Vice President Hubert Humphrey (17 percent). Unfortunately, only one of these men—a widely reviled racist—was actually running. To be sure, there was a grass-roots favorite expected to vault into contention by winning the Iowa caucuses, but it wasn’t Carter. It was Senator Birch Bayh of Indiana. Carter was netting low single digits. Newsweek explained that he could become viable “only in the long-odds event that [he] can stop George Wallace” and get the southern vote.

Four years later, Carter was, of course, president. And the late-1979 polling data strongly suggested that he would be dethroned—by Ted Kennedy. The great liberal hope for Democrats despairing of Carter’s incompetence, Kennedy had been scoring 60 percent in matchups against the incumbent earlier in the season. In the late fall he was still favored by Democratic majorities. One New York Times survey found black voters choosing Kennedy over Carter 53 to 15 percent, conservative Democrats favoring him 58 to 22 percent, and even southerners backing him 44 to 29 percent. But in the end, Kennedy triumphed in only 10 states, mostly in the Northeast.

In 1987, after the Democratic front-runner, Gary Hart, withdrew from the race following questions about his private life, the new leader, with 25 percent in the polls, was a candidate with no real prospect of winning: the Reverend Jesse Jackson. Jackson’s chief adversary was the Illinois senator and unreconstructed liberal Paul Simon, who was surging in Iowa. The party’s eventual nominee, Michael Dukakis, was in the fight, especially in New Hampshire, but The New York Times noted, “Recent surveys show him to be increasingly vulnerable in the state.”

Even further from the front of the pack one year out was Bill Clinton in 1991. While he was hovering around 6 percent, Democratic voters were overwhelmingly telling pollsters that they preferred New York Governor Mario Cuomo, who never entered the race. Among the announced candidates, the leader was California’s Jerry Brown, who was at that time known for his flirtations with Zen Buddhism, his “Governor Moonbeam” nickname, and the French filmmaker turned aide-de-camp who followed him around in a black beret. Brown was, in other words, a national joke.

In late 2003, the unstoppable Democratic juggernaut was led by Howard Dean, who was polling around 18 percent, followed by General Wesley Clark and Senator Joe Lieberman of Connecticut. Neither Clark nor Lieberman was presumed capable of derailing Dean in Iowa. Dean would be “denied the nomination,” explained the columnist George F. Will, “but only if [Richard] Gephardt wins in Iowa.” And John Kerry, who ended up winning Iowa and the nomination? Some polls had him in the single digits, just ahead of Carol Moseley Braun, the former senator from Illinois.

Four years ago, the Republican lineup was smaller than this year’s cavalcade, but the candidates’ swings of fortune were just as wild. In the fall of 2011, the leader in the polls was a nonpolitician even harder to imagine in the Oval Office than Donald Trump: the former pizza-chain CEO Herman Cain. Cain’s numbers—which went as high as 30 percent in some surveys—were at times stronger than Trump’s. He had seized the front-runner mantle, moreover, from another fleeting GOP hope, Texas Governor Rick Perry, who hit 38 percent before his moderate immigration rhetoric alienated hard-core conservatives. (Yes, Perry’s decline began before his “oops” gaffe in a November debate.) After Cain’s fall, Republican voters cycled through a Rick Santorum phase and a Newt Gingrich one before finally embracing the “inevitable” Mitt Romney as their standard-bearer.

The prevailing diagnosis this campaign season—based largely on the unexpected popularity of several candidates who, by normal measures, would stand little chance of becoming president—is that something is profoundly out of joint: An angry populism is surging. Voters are exasperated with the status quo.

But polls from previous election cycles one year out—that is, from the November before the presidential election—suggest that this picture of a surly, restive electorate may be an illusion. Could it be that the Donald’s numbers don’t really bespeak a radically new Republican temper? Or that Bernie Sanders’s numbers indicate something less than a Democratic lurch leftward? The perceived discontent and restlessness this fall may well be more noise than signal, and not at all unprecedented.

Of course, sometimes the early polls do get it right. Typically this happens in races with few competitors, as when then–Vice President Al Gore led the Democratic field throughout 1999, or in races with an overwhelming favorite, as Ronald Reagan was in 1979. William Mayer, a political scientist at Northeastern University, found that in contested primary races since 1980, front-runners polling at 34 percent or higher in September the year before the election went on to win the nomination six of eight times—but not one of the five front-runners who fell short of that threshold ultimately prevailed.

Looked at over the long run, then, early polls tend to be startlingly unreliable predictors of final outcomes. They capture not the convictions of a newly aroused and assertive body politic, but instead the fleeting impulses of an electorate that remains overwhelmingly disengaged.

The first thing to keep in mind is that a year before the general election, most voters aren’t paying attention yet. Campaign reporters and political junkies—and probably anyone reading this article—are apt to forget this, because we talk about the race incessantly ourselves. But only about 10 to 20 percent of voters are tracking the campaign closely. Normal people tend to tune out the arcane, minute developments that the Twitterati are quick to label game changers. Believe it or not, they have better things to do.

Their indifference may be justified. A California voter with a modest interest in public policy has no good reason to figure out whether she prefers John Kasich or Rand Paul or Carly Fiorina on the Islamic State or abortion or entitlements, because by the time she votes next June, there’s a good chance none of them will be in the race. She will begin studying the candidates carefully only in the days just before her state’s primary.

This inattention means that early poll numbers are based on shallow preferences. “The media don’t always report the numbers that say ‘not sure’ or ‘don’t know enough,’ ” says David Karol, a political scientist who has studied the nomination process. Many people who are actually undecided, he adds, will cough up a name when a poll-taker calls and prompts them. Those responses just don’t tell us much.

What the early numbers do reflect is name recognition. Amid all the explanations for Trump’s summer surge—his bluntness, his immigration message, his political innocence—the most important one may simply be that he’s famous. Everyone knows who he is. In contrast, names like Marco Rubio and Ted Cruz, familiar inside the Beltway, evoke shrugs or blank stares from many people. Name recognition accounts for the misleading early success of many past front-runners. It explains why the 2000 vice-presidential nominee, Joe Lieberman—who was far too conservative to ever win the Democratic primary—was the front-runner for a while in 2003. It even explains, in part, why George W. Bush bolted into first place among Republicans in 1999. Some respondents literally thought the man they were being asked about was the former president. “Despite the Governor’s popularity in the polls,” wrote Richard Berke in The New York Times in 1999, “surveys continue to show that many Republicans confuse Mr. Bush with his father.”(Name recognition also helped Jeb Bush vault to a lead in the polls earlier this year, although his weak campaign-trail performance, and perhaps lingering discontent with his brother’s tenure, led his numbers to fall.)

Besides sheer familiarity, the other big determinant of early success, according to the political scientist and Bloomberg View columnist Jonathan Bernstein, is recent media attention. Press coverage of a race is, of course, never organized or systematic. As Walter Lippmann put it, the news is a searchlight—moving about “restlessly” and “bringing one episode and then another out of darkness into vision.” The news frenzy that Trump provoked with his disparaging remarks about Mexicans in his announcement speech goosed his numbers. Media hype also fueled the surges of Gary Hart in 1984 and Howard Dean in 2004, both of whom were eventually tossed aside in favor of candidates with stronger claims to the nomination—greater stature, more-impressive achievements, broader appeal.

If recent presidential races seem especially tempestuous, it’s not because of some new climate of desperation but because media attention to the pre-primary stage of the campaign has become unrelenting. A faster news cycle, fed by round-the-clock cable news and online coverage, transforms trivial developments into uproars. The media have more to feed on, too. Intraparty debates, which used to begin late in the season, are now held months in advance of the first primaries, and are broadcast to national audiences. Strong performances can propel obscure candidates into the limelight, and weak showings can doom candidates—like Wisconsin Governor Scott Walker—who aren’t ready for the big leagues. Polls, too, used to be eagerly awaited events, with networks and newspapers soberly elucidating the implications of their proprietary surveys. Now they’re a daily fix, easily obtained through sites like RealClearPolitics, fodder for ceaseless Twitter twaddle.

And yet, as mindless as much of the current speculation may be, early-stage rough vetting does have value. Most people are still tuned out, but thanks to the scrutiny brought on by poll standings, some are starting to learn more about the candidates’ backgrounds, positions, and temperaments—and are adjusting their preferences accordingly. Through this process, we usually know enough by the time we vote to weed out likely disasters. “Over time,” says John Sides, a political scientist and co-founder of the “Monkey Cage” blog, “those polls move toward what is the fundamental equilibrium of the race.” It’s an inefficient way to winnow a field—yielding lots of unfounded proclamations about the mind of the electorate—but it gets the job done, more or less.

Still unconvinced? An alternative can be seen in the way the parties pick their vice-presidential nominee. That selection has often been kept confidential until the summer convention, or just before it, and the media vetting occurs all at once, in a mad rush, with the general-election campaign close at hand. This is the process that gave us Dan Quayle and Sarah Palin.