Overview of People I Mostly Admire with Leidy Klotz
This episode of People I Mostly Admire features University of Virginia engineering professor Leidy Klotz discussing his book Subtract: The Untapped Science of Less and the core idea that people systematically overlook subtraction when trying to solve problems. Steve Levitt and Klotz explore the research behind this “bias against subtraction,” why it happens, and where subtractive thinking can lead to better design, policy, and everyday decisions.
Main Idea: We Default to Adding
Klotz’s central argument is simple:
- When people try to improve something, their first instinct is usually to add rather than remove.
- This happens even when subtraction would be the simpler, cheaper, or better solution.
- Klotz argues this is not just a habit, but a human bias against subtraction.
Levitt agrees that the idea is genuinely new and important: subtractive solutions often remain invisible unless people are deliberately prompted to consider them.
Key Research Findings
Klotz describes a series of experiments showing that people overwhelmingly prefer addition:
Lego experiments
- Participants were shown Lego structures and asked how to improve them.
- Almost everyone added pieces; very few removed any.
- In one setup, only 1 out of 60 participants chose subtraction.
Itinerary experiments
- Subjects were given an absurdly overpacked Washington, D.C. travel schedule.
- Instead of removing activities, they often added more, making the itinerary even worse.
Symmetry/grid experiments
- Participants had to make a grid symmetrical.
- The best solution was often to remove marks from one quadrant.
- Most people instead chose a more costly additive solution.
- Even when explicitly reminded that subtraction was an option, people still tended to ignore it unless cued directly.
Cognitive load makes it worse
- When participants were distracted by a secondary task, they were even less likely to notice subtractive solutions.
- This suggests subtraction requires extra mental effort and is not the default response.
Why People Overlook Subtraction
Klotz says the bias likely comes from multiple sources:
1. Evolutionary and competence-signaling reasons
- Humans may have evolved to show competence by building, adding, and creating visible output.
- More elaborate structures can signal effectiveness, even when simplicity would work better.
2. Cultural habits
- Civilizations tend to progress by adding roads, laws, buildings, and systems.
- We are surrounded by evidence of additions, but subtraction leaves fewer visible traces.
3. Economic incentives
- Metrics like GDP often reward adding, even when the added thing is socially undesirable.
- People and institutions are often rewarded for growth, not for simplification.
4. Fear of removing something important
- In complex systems, people worry that a component was put there for a reason.
- That makes subtraction feel risky, especially when the system is poorly understood.
5. Politics and incentives
- Subtraction often creates visible losers and diffuse winners.
- That makes it politically harder to remove entrenched systems or policies.
Real-World Examples of Better Solutions Through Less
The conversation includes several strong subtractive examples:
Balance bikes / Strider bikes
- Instead of adding training wheels, the inventor removed the pedals.
- This let young children learn balance directly, making the eventual transition to a real bike much easier.
Public speaking advice
- Levitt’s speaking coach improved his presentations by recommending:
- no necktie
- no podium
- This stripped away barriers and helped Levitt become more authentic and effective.
Criminal justice / ankle monitors
- Klotz argues that bulky ankle monitors are an example of overdesigned, stigmatizing tech.
- A smaller, less intrusive alternative—more like an Apple Watch—could preserve monitoring while reducing harm and stigma.
Hollow concrete blocks
- Klotz highlights inventor Anna Keichline’s hollow building blocks.
- They use less material, are easier to transport, improve insulation, and reduce emissions.
Home renovation
- Klotz challenged students to redesign a home without adding square footage.
- In the end, the practical solution for his own home was to add space, showing subtraction is not always the answer—just one that is too often ignored.
Practical Applications
Klotz offers several ways to apply subtractive thinking:
Use “stop doing” lists
- Don’t just list what you need to do.
- Also identify what you can stop doing entirely.
Build reminders for subtraction
- Since subtraction is easy to forget, create cues that make you consider it.
- Example: mark on your calendar when you eliminate a redundant meeting.
Ask the subtraction question
- Before solving a problem, pause and ask: What could I remove?
- The point is not to always subtract, but to ensure it is considered.
Notable Takeaway
The big lesson is not “always do less.” It’s:
- Subtraction should be on the table.
- People too often assume the best solution involves adding something new.
- In many cases, the smartest improvement is to remove clutter, friction, redundancy, or stigma.
Closing Thought
Levitt ends up seeing subtraction as a surprisingly broad principle: in design, policy, personal productivity, and even identity, less can often mean better. The episode’s takeaway is a simple but powerful habit shift: when facing a problem, don’t just ask what you can add—ask what you can take away.