Psychology says people who carry one mug to the kitchen instead of waiting to carry four aren't tidy or impatient — they're spending real physical effort to stop holding the task in their head, and researchers have a word for it: precrastination

It looks like the least efficient way to clear a table.

One mug, one trip, back and forth, when waiting five more minutes would let the same person carry all four at once and cut the total number of trips by three quarters.

Efficiency experts would wince. And yet almost everyone has done exactly this, at some point, without being able to explain why beyond a vague sense that it just felt better to get it out of the way.

Psychology has spent the last decade building a fairly precise account of what that feeling actually is, and it has nothing to do with tidiness or impatience.

The bucket experiment that started it

The pattern was first documented in a 2014 study by the psychologist David Rosenbaum and his colleagues Lanyun Gong and Cory Adam Potts, published in Psychological Science. Participants walked down an alley toward a platform at the far end, with one bucket sitting near the start of the walk and an identical bucket sitting much closer to the platform. Told to pick up either bucket and carry it the rest of the way, most people grabbed the nearer one — the one requiring them to carry it for a much longer stretch of the walk — rather than the farther bucket, which would have meant far less total carrying distance.

This held even when the buckets were heavy enough that carrying one for longer clearly cost more physical effort, and even when participants had already lifted both buckets beforehand and knew exactly how much that extra effort would be. Rosenbaum coined a name for the behavior: precrastination, the opposite impulse to procrastination, the urge to get a subtask done as early as possible even at a real physical cost.

What the effort is actually buying

The explanation that has held up best since then is what researchers call the cognitive-load-reduction hypothesis, tested directly in a 2018 follow-up by Lisa Fournier and colleagues, published in Attention, Perception, & Psychophysics. The idea is straightforward once it’s spelled out: an unfinished task, even a trivial one like “remember to carry that other bucket eventually,” takes up a small amount of working memory for as long as it stays unfinished. Finishing it early clears that mental slot immediately. People in the study were, in effect, trading physical effort they’d feel in their arms for mental effort they wouldn’t have to keep paying rent on. Given that trade, plenty of people take it, every time, often without noticing they’re making a decision at all.

Two hundred million years of the same trade

In 2015, the psychologist Edward Wasserman ran a version of the bucket problem on pigeons, reasoning that if precrastination reflects something as basic as cognitive-load reduction, it shouldn’t be limited to species that carry groceries. Pigeons pecked a touchscreen through a three-step sequence to earn food, choosing between a path that deferred a location switch and one that got it out of the way early. The birds precrastinated almost every time, resolving the switch as soon as the option appeared rather than waiting.

The finding didn’t stay uncontested. A later team led by Thomas Zentall ran a version of the task structured more like Rosenbaum’s original alley walk than Wasserman’s touchscreen sequence, and got the opposite result: the pigeons procrastinated. Their argument was that Wasserman’s setup may have rewarded early switching for a more mundane reason — a conditioned association between the early cue and the payoff — rather than anything resembling a pigeon clearing a mental to-do list. Whether pigeons are actually managing something like working memory here, or just responding to reinforcement timing, is still an open question between the two labs.

What isn’t in dispute is that the underlying trade-off — pay a cost now to close out a pending outcome sooner — shows up in a species whose evolutionary line split from ours roughly 300 million years ago. Whatever precrastination turns out to be at the mechanistic level, it isn’t obviously a product of modern, overscheduled human life.

Where the mug fits

The single-mug trip runs on the same logic, even though nobody ran a controlled study on kitchen tables specifically. Waiting to carry four mugs at once means holding “still need to deal with those mugs” as an open loop for however long the wait lasts — a small, low-grade mental tab that has to stay open until the job gets done. Carrying one mug immediately closes that loop the instant it’s picked up, at the cost of making three more trips later. The physical cost is obvious and easy to price: three extra walks to the kitchen. The mental cost being avoided is much harder to see, precisely because avoiding it is what makes the open loop disappear before anyone has to notice how much it was quietly costing them.

Not a personality trait, a trade-off

None of this means every one-item trip is secretly optimal, and prolific precrastinators aren’t quietly winning some efficiency contest the rest of us are losing. Four trips is still four trips, and there are plenty of situations where waiting really is the better call. What the research does clarify is that the impulse isn’t a character flaw or a tic worth correcting. It’s a legible, fairly universal trade a mind makes constantly, choosing to spend a bit more of the body’s effort in exchange for a bit less of the mind’s, and mostly making that trade without ever putting it into words.

The grocery-bag version got tested directly

The mug scenario is an extrapolation from the bucket data, but a close real-world analog has actually been run in a lab. In a 2023 study in Psychological Research, David Rosenbaum and Julian Dettling had students carry dodgeballs — standing in for grocery bags — between two bins spaced several feet apart, letting each person choose freely how many to carry per trip and how many trips to make. If people were procrastinating, they’d save the heaviest loads for the final trips, once the end was in sight. If they were precrastinating, they’d front-load the carrying and taper off.

People front-loaded it. Participants carried more items per trip early in the sequence than late in it, mirroring the bucket results in a setup that looks a lot more like an actual chore than an alley with two buckets in it. Half the group also had to memorize and later recall a string of digits, adding a second, unrelated demand on working memory — and the added memory load nudged the pattern further toward front-loading, the direction the cognitive-load-reduction hypothesis predicts. The mug scenario, in other words, isn’t just a plausible-sounding extension of the original research. It’s close enough to a study that’s already been run.