Behaviors manifesting from zero risk bias can directly impact decision-making concerning probabilistic events. Various studies have shown that we prefer no risk to some risk. For example, if people are asked if they prefer the option to decrease a given risk from 5% to 0% or from 50% to 25%, most will opt for the former despite the drop from 50% to 25% being a far greater reduction in risk.¹ Knowing that there is no risk involved provides individuals with psychological comfort and a sense of certainty in an uncertain situation. 

However, the seduction of certainty can push us to erroneously opt for a suboptimal choice. Much of the research surrounding zero risk bias involves presenting participants with hypothetical scenarios, often labeled with probabilities in terms of risk. It is worth mentioning, however, that decisions in the real world are often not as clear-cut and defined as they are in experimental settings. But while the trade-offs that are often front and center in zero risk bias might not be applicable to everyone, the concept of having a bias towards a certain, risk-free option is still pertinent to many.

Zero risk bias is particularly strong in environments and situations where risk is emphasized,  often leading to overspending and purchasing unnecessary services and items. Imagine you’ve pre-booked a car rental for an upcoming trip, keeping within your budget of $50 per day. When you arrive at the desk to pick up your vehicle, you’re informed that your current level of insurance doesn’t cover every possible damage, and you’re offered the ‘comprehensive carefree’ package for an additional $19.99 a day. As it’s your vacation, you decide that you don’t want to worry about damaging the car the whole time you’re away, and you blow your budget in order to eliminate all risks.

Zero risk bias can have significant effects in the court of public opinion. Some of the hypotheticals in the literature include preferences over policies towards terrorism, gun violence, and traffic accidents. Public pressures to strive for zero risk may push policymakers away from prioritizing overall risk reduction.

On a business level, management decisions may be influenced by the zero risk bias. A lot of success in business, especially in regard to start-ups and small firms, comes from taking risks. With a proclivity to exhibit a bias towards eliminating risk, these companies may be missing out on major opportunities for growth. Zero-risk bias can also lead organizations to overemphasize eliminating risks entirely, even when the cost or effort to do so far outweighs the benefits. This can result in unnecessary expenditures, such as excessive safety measures or technologies that provide minimal additional protection. 

A good example of this is antimicrobial paint. Big paint brands have spent a lot of time and resources developing interior paint with sanitizing technology that, in some cases, claims to kill up to 99% of certain bacteria.¹⁸ However, as Erica Marie Hartmaan, a civil and environmental engineer from Northwestern University, points out, these paints don’t purify the air and only kill the bacteria or viruses that come into contact with the paint’s surface. So, what’s the impact of people believing that their walls alone can protect them from harmful bacteria and viruses? Their focus is shifted from other high-touch areas like doorknobs, elevator buttons, and taps that harbor more bacteria than walls, potentially exposing them to a greater risk of infection. And the paint companies? Well, Hartmaan believes they’re wasting their time as bacteria don’t like dry, barren surfaces like those that are painted anyway. 

Like many cognitive biases, the zero risk bias is a mental shortcut. The common narrative behind these shortcuts is that they reduce cognitive strain. Instead of having to calculate the optimal solution, something that would require a lot of time and energy, we opt for the choice with less effort and uncertainty.

A classic behavioral science concept that can help explain the lure of 0% is loss aversion. Kahneman and Tversky’s Prospect Theory,² which suggests that losses loom larger than gains, provides a more detailed explanation. By completely eschewing risk, we are eliminating the possibility of a loss, which can be reassuring enough to become more valuable than an increased probability of a gain.

Consistent with this line of thinking is the “risk-as-feelings” hypothesis from the behavioral economist George Lowenstein and colleagues.³ They suggest that in uncertain situations, the possibility is more emotionally salient than the probability of an outcome. These emotional cues are relied upon when making decisions regarding uncertainty, and manifest in mental shortcuts such as the zero risk bias.

Other cognitive biases and processes also influence zero risk bias. The framing effect, which describes how our decisions are influenced by the way information is presented, can reinforce the zero risk bias when we’re trying to make a choice. Imagine you’re buying medication for seasonal allergies. You see two similar products with the same active ingredients but different labelling: 

Option A: Proven effective for 95% of people. ($3 per pack)

Option B: Guaranteed to eliminate all your symptoms! ($6.50 per pack)

Clearly, both medications work effectively, but the framing of Option B as "guaranteed" makes it feel like the safer choice, even though it’s much more expensive. The framing of these products emphasizes certainty in Option B, amplifying the zero risk bias—the desire to eliminate any chance of discomfort, regardless of cost or practicality.

Decision-making under risk and uncertainty is a vast arena present in public health, financial markets, political strategy, security, and business management. Decisions within these domains can have serious consequences, so balancing a public desire for certainty with the real optimal option can be a delicate act. Not only is acknowledging the zero risk bias relevant to an individual’s thought process, but also to how we might expect such decisions to be perceived by others.

While zero risk bias may make us feel safer and help us to avoid unpleasant surprises, in some contexts, it can actually hold us back. In the context of medical innovation, zero risk bias can delay the adoption of new treatments or important trials. 

Take, for instance, bone marrow transplantation. Although the idea had been around for decades, it wasn’t until the 1950s and 1960s that doctors started to put theory into practice. Initially, doctors were hesitant to adopt it due to the high risk of complications like infection, rejection, and graft-versus-host disease. The procedure itself was fraught with uncertainty, and the outcomes were unpredictable.¹⁷

On top of these risks, doctors and medical institutions felt that the existing treatments for conditions like leukemia and other hematological diseases, though less effective, were safer and more familiar. 

It wasn't until the 1970s and 1980s, with improved techniques, better understanding of immunosuppressive therapy, and advances in matching donor-recipient pairs, that bone marrow transplants became more widely accepted. The initial delay can be attributed, in part, to the zero risk bias. The medical community favored the known, albeit less effective, methods over the risky new approach, even though the latter offered the potential for significant breakthroughs in treating life-threatening diseases.

Despite the risks, bone marrow transplant pioneers such as American physician E. Donnell Thomas persevered because they believed that the potential for breakthrough far outweighed the initial risks involved. 

Many argue that embracing risk and potential failure is essential for both individual growth and solving the complex challenges we face across the globe. Take, for instance, global health. Bold ideas such as a single at-home test for cancer or human eye transplants may be a reality one day, but some risk must be taken to translate these ideas into action. By taking a slightly risk friendly approach to global health challenges, it is believed that more breakthrough solutions will occur, even if it means navigating multiple failures and setbacks along the way.¹⁶ 

The same applies to individual growth. Life and business coaches are often heard proselytizing that while avoiding risk entirely may feel safe, it often leads to stagnation. Some degree of risk, on the other hand, allows for learning, adaptation, and the potential for greater long-term  success.

But how do we become less risk averse? This one is difficult because we all have different comfort levels when it comes to risk taking. Going out without an umbrella on a cloudy day may feel to one person what investing their life savings in a startup feels like to another. 

While it’s not always easy to stop and think about what a rational actor would do, it helps to assess your decision-making process and see how much fear or the emotional salience of a potential loss is guiding your preference towards a particular choice. Probe yourself on how much the allure of zero risk is influencing your preferences and whether it’s really more important than a greater reduction in risk.

Assessing risk from both emotional and data-based perspectives is also important. We can’t completely override our emotions, so it’s important to make decisions based on what we feel and what the data tells us. If the forecast says it’s unlikely to rain, but you know you’ll be constantly worrying about the potential of being caught in the rain, it’s probably better to put the umbrella in your bag. 

Augmented Reality (AR) and Virtual Reality (VR) technologies also have the potential to significantly transform the way project risks are identified, assessed, and understood.19 These technologies enable stakeholders to experience and interact with complex data and potential risk scenarios in a more intuitive and immersive way, providing a three-dimensional, interactive environment that traditional methods of analysis cannot offer.

Imagine a large-scale infrastructure project, such as the construction of a new bridge. Project managers and engineers can use VR to simulate the construction process, allowing them to visualize potential hazards like structural weaknesses, environmental impacts, or supply chain disruptions before they occur. By immersing themselves in a 3D model of the project, they can examine risk factors from every angle, simulate various failure scenarios, and identify potential issues in real time. These technologies will enable project managers and decision-makers to make informed decisions about potential risks and how to balance them with innovation and client needs. 

Zero risk bias as a unique cognitive phenomenon is often attributed to a 1987 paper published by Kip Viscusi, Wesley Magat, and Joel Hubert.⁴ The researchers found evidence for “certainty premiums” in eliminating risk by asking participants how much they would pay to reduce the possible risk of side effects from cleaning products (insecticide and toilet bowl cleaner). Viscusi and colleagues found people were willing to pay up to three times as much to reduce the risk of side effects from 5/15,000 cases to 0/15,000, as they were for a risk reduction from 15/15,000 to 10/15,000, despite the reductions in risk essentially being statistically negligible.
However, our preference for certainty over overall risk reduction has been explored across numerous fields for much longer. One of the most famous examples of this tendency can be found in behavioral economics. The Allais Paradox is a choice set included in Maurice Allais’ 1953 paper published in Econometrica⁵ and sets out a problem based on a hypothetical choice between two options.

People routinely express a preference for Option A, despite the expected value for Option B being much greater. Although Option B’s trade-off of having a 10% chance of earning an additional $400 million in exchange for the remote 1% of not collecting anything is well worth the gamble from a rational perspective, people are deterred by the sliver of risk and opt for the option with zero risk despite it being the suboptimal choice.

Have you ever been watching an infomercial and just when you think they can’t sweeten the deal any more than they already have (call now, and they’ll quadruple the offer!), they say that if you’re not happy with the product, you can get your money back — guaranteed.

The money back guarantee is not just a tactic used on the shopping channel but across a number of consumer goods. It’s a widespread marketing tool that is largely successful due to its ability in leveraging the zero risk bias. The money back guarantee seduces consumers by eliminating the risk of a prospective purchase decision. Much of the risk in buying a product comes from the probability that you won’t be satisfied with it, but with the option of receiving a full refund if a buyer is unsatisfied, then the risk is no longer a worry.

The evidence on the subject offers support for the efficacy of the money back guarantee, with research having found that retailers using the money back guarantee see a boost in sales and profit,⁶ as well as increases in customer satisfaction and customer loyalty.⁷

There are many other tactics used in marketing that leverage the zero risk bias to enhance customer experience and get people to buy products and sign up for services. A free trial period, for example, enables people to try a product or a service with no immediate financial commitment, thus eliminating the risk of making a poor investment if they don’t like it. In a similar vein, no-contract plans and free cancellation policies for mobile phone services and internet packages can help eliminate the risk of being locked into a long-term commitment. If a customer knows they can opt out whenever they want without a penalty, they are more likely to sign up.¹¹ Online shopping behaviors are also driven by zero risk bias. By offering free returns, people are more likely to purchase items that they're not able to try before buying.

Think back to the first time you were asked to use an AI tool to complete a task. What was your initial reaction? Like many people around the world, you may have felt slightly anxious at the idea of trusting a ‘machine’ with an important task that usually you’d complete yourself. Unfortunately, the zero risk bias may be a significant barrier for many people to use AI-generated solutions in their everyday lives. A 2023 study on global attitudes towards AI conducted by KPMG and the University of Queensland found that three out of five people (roughly 61%) are either ambivalent or unwilling to trust AI, with most people (roughly 73%) perceiving significant risks with the tools.¹⁰ 

But what are the perceived and actual risks of AI that we should be weighing up before we decide to ditch it altogether? Firstly, there’s been a lot of discussion about the risk to people’s jobs as a result of increasingly adopting AI tools in the workplace. According to the zero risk bias, an individual worried about losing their job to AI may choose not to engage with these tools despite the fact that AI can actually enhance their efficiency and perhaps even make them better at their job. Others have highlighted the issue of bias in machine learning, resulting in pushback against using AI for particularly sensitive data analysis and protected topics. 

In order to eliminate these risks, some people may prefer to stick to less efficient traditional systems, even when AI offers significant overall benefits. In fact, we tend to hold AI to much higher standards when it comes to margin of error than other humans. A survey of staff at the Department of Radiology at Bispebjerg-Frederiksberg University Hospital, Copenhagen, Denmark, found that people have significantly lower acceptable error rates for AI (6.8%) than humans (11.3%).¹⁴ 

Since 2006, teenagers across the world have been vaccinated against the Human Papillomavirus or HPV. However, vaccine hesitancy among many parents and caregivers remains high due to concerns about side effects⁸. 

According to the American Cancer Society, the vaccine can eliminate more than 90% of HPV cancers when given at the recommended age.¹² That’s a lot of risk eliminated. Yet for many, reducing the risk of perceived side effects (such as infertility and autoimmune problems) to 0% by not taking the vaccine is more important than the long-term benefits it brings.¹³

In addition to zero risk bias, research has found that parental HPV vaccine hesitancy is also associated with omission bias. In one study which looked at how cognitive bias affects vaccine uptake, the researchers found that vaccine-hesitant participants were more likely to exhibit omission bias, which was associated with a belief that vaccinating posed a greater danger than not vaccinating.⁹ This pattern of thinking is similar to that found in zero risk bias, where individuals choose the option that they perceive reduces all possible risks. In this case, the choice not to vaccinate. 

The COVID-19 pandemic (remember that?) presented us with almost unprecedented levels of risk and uncertainty. On a daily basis, we were compelled to take conflicting information from multiple sources and make what often felt like life-and-death decisions about our and our family’s health. 

From the outset, people went to extreme, and often bizarre, lengths to eliminate risk and bring some semblance of certainty to their everyday lives. Across the world, reports of panic buying and toilet paper theft hit the headlines as people desperately looked for ways to avoid the risk of running out of this essential item.¹⁵ In actual fact, global stocks of toilet paper were entirely sufficient to cover everyone and then some. 

Panic buying wasn’t unique to the pandemic. It’s an irrational response to the fear of going without something we deem essential to our everyday existence and occurs when there’s an anticipated shortage of a certain product or a predicted disaster. By eliminating one threat entirely—the risk of having no toilet roll—we free up some mental capacity to deal with the real threat that we have no control over (a tornado, for example).

What it is

Zero risk bias refers to our tendency to opt for the complete elimination of risk, sometimes over an alternative that actually offers greater overall predicted outcomes.

Why it happens

Choices with zero risk offer certainty, which the brain seeks to maximize in order to reduce cognitive strain. Additionally, losses loom larger than gains, and the prospect of a loss drives us to eschew that possibility even if it leads to a suboptimal choice.

Example 1 - HPV vaccine

Despite strong research highlighting the safety of the HPV vaccine, hesitancy among many parents and caregivers remains high due to concerns about side effects. For many, reducing the risk of perceived side effects to 0% by not taking the vaccine is more important than the long term benefits it brings. In this case, the zero risk bias is linked to the omission bias, our tendency to react more strongly to harmful actions rather than harmful inactions. 

Example 2 - Panic buying

During the COVID-19 pandemic, panic buying and theft of toilet paper sky-rocketed, fuelled by the zero risk bias and people’s desire to eliminate at least one risk (running out of toilet paper) from their lives. 

How to avoid it

It can help to review your goal in making a decision. Is your goal overall risk reduction? Or does completely eliminating risk carry more value? Monitoring your emotion to see if it’s leading you astray from your decision-making goals can sometimes help mitigate the zero risk bias.

What Does China Approaching Epidemic Peak Mean For Us? Communicating Risk in the Age of Social Media

This article talks about the importance of adequately communicating risk to the public during the COVID-19 pandemic. As the zero risk bias shows, our perceptions of risk are not always “rational”.

CO2 Out of Sight, Not Out of Mind: Carbon Capture and Storage Risks

This article references the zero risk bias as a potential barrier to carbon capture. In the future, people may oppose a carbon capture facility as a way to eliminate the risk of possible leakage, rather than opt for the facility which can help reduce the greater risk of climate change.