WHAT would you rather do: live 60 happy years, or 60 happy years followed by five only slightly happy years? Chances are you'd take the latter. But when psychologists put this questions to subjects regarding a fictional third person, they rate the woman whose last five years were unhappier than the rest of her life as having had a worse life. Five extra moderately happy years, and yet the change assumes an outsized role in people's minds. As Daniel Kahneman explains here, we give too much weight to a) the peaks and b) the ends of periods, rater than logically evaluating their entire duration. Humans naturally invent and tell stories, and we care very much how the story concludes.

The "peak-end" effect is one reason why November's election is important for Republicans—particularly the "end" bit of it. Their timing has been unlucky in the past three elections. Here's one highly salient economic statistic, unemployment, with the election months marked by dots and the larger period around the end of those terms boxed off. Many voters associate George H.W. Bush with recession, Bill Clinton with a boom, and George W. Bush with a catastrophic recession. Most voters don't compare the two Bushes' and Mr Clinton's best numbers, or they would find the three presidents roughly comparable. The end effect, even more than the peak effect, seems quite strong. George H.W. Bush presided over an economy that was starting to improve, but the results didn't register with voters fast enough. George W. Bush clearly inherited the beginning of a recession from Mr Clinton, but in most people's mental ledger, it is assigned to its inheritor. Little needs repeating here about the economy Barack Obama inherited from the second Mr Bush. It does seem likely, not only from the graph but from the fundamentals, that unemployment will continue to fall, even if it cannot fall fast enough for voters today. If Mr Obama wins in November—and it is now undeniable that he is the frontrunner—what matters in the historical ledger is how things look in 2016. He stands a good chance of reaping the benefit of the economy's spare capacity (including workers) finally being put back to use. If he is so lucky, voters will have experienced a 28-year run of Republicans' presidencies ending in perceived recession, and Democrats seen as managing improving economies. That's a generation. The youngest voters to have voted for Ronald Reagan, the last "successful" Republican steward of the economy, will be 50 years old in 2016. Most will be much older.

I put "successful" in scare-quotes because none of this is fair. Why don't Reagan's Democratic Congress or Mr Clinton's Republican Congress get any credit? The vast majority of the economy is out of the president's direct control. The peak-end effect is irrational. But none of this matters. If Mr Kahneman is right, this is simply how humans think, and the result makes 2012 critical for Republicans. They once had a strong reputation as the better stewards of the economy. By 2016, if Barack Obama is still in the White House, that may be something most adults consider a nostalgic reminder of the 1970s and 1980s. The stars of disco and hair-metal are now starting to die of old-people diseases. If Mitt Romney pulls out the election he can remind younger voters that Republicans, too, can be associated with good economic management (or at least good luck).