Why Our Brains Miss Opportunities to Improve Through Subtraction

Summary: Study explains the human tendency to look at a situation, or object, that needs improvement in different contexts, and instead, generally believe adding an element is a better solution than removing one.

Source: University of Virginia

If, as the saying goes, less is more, why do we humans overdo so much?

In a new paper featured on the cover of Nature, University of Virginia researchers explain why people rarely look at a situation, object or idea that needs improving — in all kinds of contexts — and think to remove something as a solution. Instead, we almost always add some element, whether it helps or not.

The team’s findings suggest a fundamental reason that people struggle with overwhelming schedules, that institutions bog down in proliferating red tape, and, of particular interest to researchers, that humanity is exhausting the planet’s resources.

“It happens in engineering design, which is my main interest,” said Leidy Klotz, Copenhaver Associate Professor in the Department of Engineering Systems and Environment. “But it also happens in writing, cooking and everything else — just think about your own work and you will see it. The first thing that comes to our minds is, what can we add to make it better. Our paper shows we do this to our detriment, even when the only right answer is to subtract. Even with financial incentive, we still don’t think to take away.”

Klotz, whose research explores the overlaps between engineering and behavioral science, teamed with three colleagues from the Batten School of Leadership and Public Policy on the interdisciplinary research that shows just how additive we are by nature. Batten public policy and psychology faculty, assistant professor Gabrielle Adams and associate professor Benjamin Converse, and former Batten postdoctoral fellow Andrew Hales, collaborated with Klotz on a series of observational studies and experiments to study the phenomenon.

This shows a tower made out of lego blocks
How would you stabilize this Lego structure to support the weight of a masonry brick placed on the top platform? University of Virginia researchers found most people in their study defaulted to adding a block at each corner, rather than removing the existing block to allow the platform to rest on the layer below. Credit: University of Virginia

When considering two broad possibilities for why people systematically default to addition — either they generate ideas for both possibilities and disproportionately discard subtractive solutions or they overlook subtractive ideas altogether — the researchers focused on the latter.

Credit: Nature

“Additive ideas come to mind quickly and easily, but subtractive ideas require more cognitive effort,” Converse said. “Because people are often moving fast and working with the first ideas that come to mind, they end up accepting additive solutions without considering subtraction at all.”

The researchers think there may be a self-reinforcing effect.

“The more often people rely on additive strategies, the more cognitively accessible they become,” Adams said. “Over time, the habit of looking for additive ideas may get stronger and stronger, and in the long run, we end up missing out on many opportunities to improve the world by subtraction.”

Klotz has a book that takes a wider view of the topic, Subtract: The Untapped Science of Less, coming out a week after the Nature paper. Although the timing is coincidence, both the paper and book are products of the interdisciplinary and collaborative research environment at UVA, he said.

“It’s an incredibly interesting finding, and I think our research has tremendous implications across contexts, but especially in engineering to improve how we design technology to benefit humanity,” Klotz said.

About this neuroscience research news

Source: University of Virginia
Contact: Jennifer McManamay – University of Virginia
Image: The image is credited to University of Virginia

Original Research: Closed access.
People systematically overlook subtractive changes” by Gabrielle S. Adams, Benjamin A. Converse, Andrew H. Hales & Leidy E. Klotz. Nature


People systematically overlook subtractive changes

Improving objects, ideas or situations—whether a designer seeks to advance technology, a writer seeks to strengthen an argument or a manager seeks to encourage desired behaviour—requires a mental search for possible changes.

We investigated whether people are as likely to consider changes that subtract components from an object, idea or situation as they are to consider changes that add new components. People typically consider a limited number of promising ideas in order to manage the cognitive burden of searching through all possible ideas, but this can lead them to accept adequate solutions without considering potentially superior alternatives.

Here we show that people systematically default to searching for additive transformations, and consequently overlook subtractive transformations. Across eight experiments, participants were less likely to identify advantageous subtractive changes when the task did not (versus did) cue them to consider subtraction, when they had only one opportunity (versus several) to recognize the shortcomings of an additive search strategy or when they were under a higher (versus lower) cognitive load.

Defaulting to searches for additive changes may be one reason that people struggle to mitigate overburdened schedules, institutional red tape and damaging effects on the planet.

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  1. In grade school, we were always taught to perform on the positive side of the grid, which is adding, not the negative side of the grid. Think about it. We climb mountains. We don’t generalize going down the other side of the mountain. We use building blocks, not undoing blocks. How have we been taught to take a block away? We haven’t. We knock them all down at once and get scorned for doing so. Now we have a mess on our hands to pickup. This is our mindset. We’re always striving and looking for new ways to create, to build, to implement, to construct, to rail. It’s what has been taught in us to become successful and improved upon. The less is better is a struggle for me. It really is!!! As kids, in our household, we were served Thanksgiving size meals at every mealtime and if we didn’t eat every bit of what was on our plates, our daddy beat us with a leather belt for eating food. Why did he get the choice of how much food we got?? Why was it considered wasting?? These taught values are of no value at all, but it’s programmed in there. Do you see what I’m talking about?

  2. Well, the simple rule: **Always substract!** invariably leads to zero or a deficit! Whereas the simple rule: **Always add!**, even in the face of errors is bound to achieve results, (ruling out catastrophic explosions). In biological terms the first rule requires an extra test for zero or negative before putting the result to test (objective), while the second rule can be immediately tested against goals without caring for an anomalous result, like dividing by zero, which makes for a small cost/simpler advantage in behaviour selection, provided on average add solutions fare better than substract solutions. Also the Life Principle of Multiplicity of Entities moves in the same direction, Life looks for more, not less, Life; less individuals may not be able to withstand all and any Abiotic pressures. In terms of Reason uncertainty guarantees always increasing maximizes/optimizes utility, but that s the viewpoint of Economics.

  3. Most real ‘engineers’ will assume that the single block serves a purpose, most likely to achieve the necessary height. Only an idiot would put that single block there when it serves no purpose. So the average ‘real’ Engineer will suggest adding 4 blocks etc. This is not an ‘addition-bias’. This is simply an ‘assuming-the-guy-who-designed-it-is-not-a-moron-bias’.
    The professor who came up with this clever design is not an engineer, if he is, he is a moron.
    Most of us assume such morons are weeded out in engineering school :)

  4. Per the picture at the top of the article… The reason people add blocks “to stabilize the structure” is because what we’re asked to do is to be applied to the entire structure which logically includes the one extra block in the middle so this is a bad example. IMHO

  5. There’s an important difference between improving and rebuilding. When I come across an existing solution that I need to improve, i’m going to assume existing elements are there for a reason. Surely the tower needed the height provided by the middle block, or the platform needed the cooling allowed by the empty space, or something similar. Why would I assume the person who built the initial structure was so incompetent as to add something that was unnecessary to meeting the problems initial parameters? Now, if you supply me with all initial parameters, and request that I build a structure that fits them, then I’m in “rebuild” mode rather than “improve” mode, and I will quickly eliminate unnecessary design features. The end product of my rebuild will be superior to my improvement, but rebuilding requires expending additional resources upfront, since I must put in the time to make sure the previous engineer didn’t have a good reason for building it the way (s)he did.

    1. Totally agree. We assume that the previous engineer wouldn’t put redundant blocks like a 2 year old (maybe an insult to many two year olds). Also, since removing that block changes the height, we, real engineers are more likely to assume the previous engineer put that to raise the height, but was running short on blocks so he couldn’t put a whole layer.

  6. I wonder if it has anything to do with if it has to do with how people look at the idea of whole. Addition of four blocks on the tower stabilizes the tower as a whole. While taking a block away is stabilized, but no longer whole.

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