A few years ago, at the at the insistence of my wife at the time, I went to the hospital with an almost imperceptible pain in my abdomen, which had been ongoing for 24 hours. I was seen by an emergency doctor, who ordered blood work and an ultrasound. The blood work confirmed her initial suspicion: appendicitis. However, the ultrasound was inconclusive. These results, combined with my nonchalant disposition, confused the doctor. “Are you sure you barely feel any pain?” she asked, scratching her head. “Yes, almost no pain at all,” I insisted, thinking I would be on my way in a matter of minutes. Instead, she said, “Something is off. I am not discharging you until you see the general surgery specialist.” When the specialist arrived, he asked me a couple of questions, quickly eyed the chart, and very confidently said, “You, sir, have appendicitis and need surgery—now!” The diagnosis took him less than a minute. And yet, he was right.
In seconds, these two doctors spared me from a major infection and potential complications. As a behavioural scientist, I wondered how the specialist made the right decision so quickly and whether other doctors could learn to do the same.
One answer to these questions lies in the emerging science of boosting. With the appropriate combination of expert knowledge, experience, and training, anyone can develop, learn, and teach the ability to make quick, accurate decisions with limited information.
In this blog post, I will provide a brief introduction to the concept of boosting.
Leveraging Heuristics: The Basis of Boosting
In 2023, I attended the Summer Institute on Bounded Rationality, hosted by the Center for Adaptive Rationality in Berlin. The theme was ‘the Science of Boosting’. Though there were many takeaways, one stands out: Gerd Gigerenzer’s session on the usefulness of heuristics. This sounded surprising and contrary to my own views at the time, as I thought of heuristics as flawed ways to make decisions and solve problems.
Heuristics are simple decision rules, rules of thumb, or mental shortcuts that enable us to navigate the world and make decisions quickly and without conscious effort (Gigerenzer et al., 2022).
The positive aspects of heuristics have actually long been recognized. In fact, in one of their seminal papers, Amos Tversky and Daniel Kahneman wrote:
“…heuristics are quite useful, but sometimes they lead to severe and systematic errors.” (Tversky & Kahneman, 1974) [emphasis added]
As Tversky and Kahneman noted, heuristics are useful. What makes them problematic is that we use them unconsciously and indiscriminately even in situations when they lead to biases or errors. As a result, we make incorrect choices more often than we should.
Boosting focuses on heuristics’ usefulness. It is the process of training individuals to deliberately use heuristics when they lead to accurate, unbiased, and nuanced decisions, and avoiding them when they lead to systematic errors (Hertwig & Grüne-Yanoff, 2017).
When Should You Use Boosts?
Boosts are useful when we want to empower citizens to make their own decisions. For example, when addressing dis/misinformation (Kozyreva et al., 2024). While it might be technologically feasible to protect citizens from exposure (e.g., by placing warnings on Instagram), there is a risk of infringing free speech, inciting backlash, or prompting legal challenges. For this reason, boosts might be a better fit because they can equip citizens with tools to decide for themselves what is real information vs. dis/misinformation.
Boosts are also ideal for situations where it is impractical to modify the choice environment; for example, when preventing phishing attacks (criminals’ attempts to obtain sensitive information by posing to be a legitimate institution or person). While cybersecurity systems can filter many malicious messages before they make it to people’s inboxes or phones, some still pass through. Since one successful phishing attack is enough to cause a big data breach, organizations must ultimately rely on employees’ behaviour. Consequently, boosting users’ judgment and decision-making is necessary to enhance cybersecurity.
Boosts are not only an alternative solution when nudges are impractical. Many situations are suitable for both nudges and boosts. For example, vaccine distribution programs can use SMS reminders to increase appointments and also use boost-enhanced marketing to address misconceptions about vaccines.
“Boosting focuses on heuristics’ usefulness. It is the process of training individuals to deliberately use heuristics when they lead to accurate, unbiased, and nuanced decisions, and avoiding them when they lead to systematic errors.”
Which Heuristics Can Be Turned into Boosts?
In principle, all heuristics can be turned into boosts if you know why and when they are helpful. In practice, though, heuristics need to be communicable to be transformed into boosts. Vague intuitions that people “cannot put their finger on” are not suitable because they cannot be distilled into simple rules and cannot be tested for accuracy and reliability.
Researchers working with the Center for Adaptive Rationality have tested dozens of boostable heuristics (Herzog & Hertwig, 2024). Using methods from behavioural science, they have been able to determine when heuristics lead to decisions that are just as good or better than their “slow thinking” alternatives. These heuristics include fast and frugal trees, interactive decision tools, and lateral reading, which have been proven to effectively support decision making (Herzog & Hertwig, 2024), risk communication (Wegwarth et al., 2023), and detection of misinformation (Kozyreva et al., 2024), respectively.
Boosting isn’t limited to heuristics discovered by academics. If you identify a heuristic that an expert in your organization has developed, you can use behavioural science methods to transform it into a boost. My appendicitis story serves as an example:
When I had a follow-up appointment with the general surgery specialist, I had a chance to ask him how he diagnosed my appendicitis so quickly. His answer was, “I have seen hundreds of patients; you are not the first one with a high threshold for pain.”
Knowing what I know about boosting today, I could explore more about the rules that the specialist used, and when and how he balanced different symptoms to arrive at correct diagnoses. The rule could hypothetically be “if a patient presents elevated white blood cell counts and C-reactive protein but only modest pain for more than 24 hours, then determine appendicitis.” This expertise could then be distilled into a set of heuristics. We could look at hospital data of patients presenting with different variations of these symptoms (including acute pain or lack thereof) and use statistical tools to determine how accurate these heuristics are (or, in technical terms, their sensitivity and specificity). If the heuristics meet objective standards of diagnosis, we might then develop a decision support tool and/or train doctors, so they, too, can make correct diagnoses quickly. In doing so, we could theoretically spare patients’ and doctors’ precious time.
This approach is more than a theoretical conjecture. In fact, while I was working at BC Children’s Hospital, we developed a decision tool to enable emergency nurses and physicians to diagnose patients presenting with mental health complaints without the need to consult a specialist. Dubbed HEARTSMAP, this tool combined a set of heuristics to diagnose and make decisions for pediatric mental health patients. Its accuracy (sensitivity and specificity) was equivalent to decisions made by experienced doctors. Importantly, HEARTSMAP reduced emergency wait times for mental health patients by 80 minutes and reduced return visits within 30 days by 15% (Ishikawa et al., 2021).
Concluding Remarks
Thanks to boosting, behavioural insights practitioners now have more tools at their disposal to tackle behavioural challenges.
The science of boosting emphasizes the redeemable qualities of heuristics and reminds us that human beings are marvellous creatures who learn and adapt as they experience the world and its uncertainties. In the face of climate change, political polarization, inequality, and distrust in science, keeping this in mind can help us when confronting such daunting challenges and high stakes.
Resources
If you are interested in learning more about boosts and their applications, here are some resources:
An overview of “The Science of Boosting” from the Center for Adaptive Rationality at the Max Planck Institute
Unraveling Behaviour podcast, Episode 5 “Ralph Hertwig: Beyond Nudging—How Boosting Empowers Citizens to Make Good Decisions”
An article on “Moving from nudging to boosting: empowering behaviour change to address global challenges” by Ralph Hertwig and colleagues.
References
Gigerenzer, G., Reb, J., & Luan, S. (2022). Annual Review of Organizational Psychology and Organizational Behavior Smart Heuristics for Individuals, Teams, and Organizations. Annu. Rev. Organ. Psychol. Organ. Behav. 2022, 9, 171–198. https://doi.org/10.1146/annurev-orgpsych-012420
Hertwig, R., & Grüne-Yanoff, T. (2017). Nudging and Boosting: Steering or Empowering Good Decisions. Perspectives on Psychological Science, 12(6), 973–986. https://doi.org/10.1177/1745691617702496
Herzog, S. M., & Hertwig, R. (2024). Boosting: Empowering Citizens with Behavioral Science. 7, 2024. https://doi.org/10.1146/annurev-psych-020924
Ishikawa, T., Chin, B., Meckler, G., Hay, C., & Doan, Q. (2021). Reducing length of stay and return visits for emergency department pediatric mental health presentations. Canadian Journal of Emergency Medicine, 23(1), 103–110. https://doi.org/10.1007/S43678-020-00005-7/TYPE/JOURNAL_ARTICLE
Kozyreva, A., Lorenz-Spreen, P., Herzog, S. M., Ecker, U. K. H., Lewandowsky, S., Hertwig, R., Ali, A., Bak-Coleman, J., Barzilai, S., Basol, M., Berinsky, A. J., Betsch, C., Cook, J., Fazio, L. K., Geers, M., Guess, A. M., Huang, H., Larreguy, H., Maertens, R., … Wineburg, S. (2024). Toolbox of individual-level interventions against online misinformation. In Nature Human Behaviour (Vol. 8, Issue 6, pp. 1044–1052). Nature Research. https://doi.org/10.1038/s41562-024-01881-0
Tversky, A., & Kahneman, D. (1974). Judgment under Uncertainty: Heuristics and Biases. Science, 185(4157), 1124–1131. https://doi.org/10.1126/science.185.4157.1124
Wegwarth, O., Mansmann, U., Zepp, F., Lühmann, D., Hertwig, R., & Scherer, M. (2023). Vaccination Intention Following Receipt of Vaccine Information Through Interactive Simulation vs Text among COVID-19 Vaccine-Hesitant Adults during the Omicron Wave in Germany. JAMA Network Open, 6(2), E2256208. https://doi.org/10.1001/jamanetworkopen.2022.56208
About the Author
Dr. Takuro Ishikawa is a senior behavioural scientist at the BC Behavioural Insights Group and serves as co-chair of the BC Centre for Disease Control Indigenous Knowledge Translation Group.
His work has been recognized by the Joachim Herz Foundation, the AUTO21 Network of Centres of Excellence, the UBC Public Scholars Initiative, the R. Howard Webster Foundation, and the British Columbia Institute of Technology. Dr. Ishikawa has a doctoral degree in experimental medicine and is a registered professional psychologist in Colombia.