A behavioral look at sports betting

I've grown deeply uncomfortable watching football matches over the past few years — because of the massive, blatant, exaggerated presence of sports betting ads. If you've been following the World Cup or the latest matches of Brazil's national league, you've probably noticed the same thing. They're everywhere: on jerseys, along the edges of stadiums, in commercial breaks, on street billboards, in any entertainment event sponsorship. That level of exposure is paying off: the online betting market projects roughly R$310 billion (about US$60 billion) in online bets during the World Cup, with around 10% of that coming from Brazil.

Even as social awareness of betting's negative consequences has grown, its presence remains deeply embedded in society. For many, it's a matter of choice — the same way we might choose a slice of chocolate cake or a beer now and then.

But where exactly is the thin line between individual autonomy and being shaped by the structures around us? In the context of online gambling and sports betting, an appeal to entertainment and leisure justifies platforms that exploit automatic behavioral mechanisms, driving compulsive use and negative consequences. There's a need for system-level solutions to change this picture, and behavioral science can help us understand why and, more precisely, how that change needs to happen.

As personal technology has spread over the past few decades, betting has flourished right alongside it. What used to be an in-person, regulated activity found room to grow inside loosely regulated offshore operations, helped along by the broader access and availability technology provides. Beyond traditional gambling, sports betting specifically has surged in popularity. Tied to the entertainment and sports-leisure industry, platforms expanded and paved the way for other forms of online gaming. Popularity grew in large countries like the United States and Brazil, culminating in legalization — justified as a way for governments to collect tax revenue on and regulate an activity that already existed.

While legalizing online gambling can bring certain benefits — economic growth driven by the sector, higher tax revenue on something that already existed, and meeting a leisure demand that is, to some extent, an individual choice — the rise in negative consequences for individuals and society points to a real problem, and opens up important discussions about how to regulate these activities.

In 2018, the U.S. Supreme Court struck down a 1992 federal law that barred most states from allowing sports betting. According to the American Gaming Association (AGA), in February 2024 — Super Bowl month — Americans bet $10.49 billion on sports, a 24.8% increase over the same period the year before, with an estimated 67.8 million people involved. Nearly $120 billion in legal bets were placed in 2023. Yet recent studies have shown that households in states where gambling was legalized saw significant reductions in savings and asset investment (Hollenbeck et al., 2024). Similarly, in states where sports betting was legalized, residents' aggregate credit scores dropped and bankruptcies rose (Baker et al., 2024). A recent study also found that when an NFL home team loses, the likelihood of a domestic violence incident is twice as high in states where gambling is legal compared to those where it isn't (Matsuzawa & Arnesen, 2024). Google searches for help with gambling addiction have risen a cumulative 23% nationally since sports betting was legalized (Yeola et al., 2025).

Online gambling was legalized in Brazil the same year. Since then, it has been heavily promoted at sporting events — sponsoring all 20 clubs in Brazil's top football division, accounting for roughly 70% of the sector's total sponsorship spend — and through digital influencers and advertising. The market went unregulated for a period, during which businesses expanded with no proper oversight. It grew 160% between 2021 and 2023, making Brazil the third-largest sports betting market in the world, behind only the United States and England. Total spending in the sector reached $11.1 billion (R$54 billion) between January and November 2023 (Dias, 2024). Recent surveys estimate that around 13–15% of the population (more than 20 million people) is involved in online sports betting. The rate is higher among young men, reaching 30% among those aged 16–24 (Datafolha, 2024). Half of them say they've lost more money than they've won. A Federal Senate survey found that 52% of bettors earn up to two minimum wages, and 58% have overdue debts. Another survey found that 17% of recipients of Bolsa Família, Brazil's conditional cash transfer program, spend money on sports betting (Terra, 2024).

Stories abound of people who've lost their savings, homes, relationships, and mental health. More than 574,000 people have already used the Ministry of Finance's self-exclusion platform, a centralized system that blocks a person's national tax ID from accessing every betting operator at once. Nearly half (41%) said the request was driven by losing control over their gambling and by negative impacts on their personal, family, and social life. Meanwhile, demand for public mental-health treatment for online gambling addiction has grown 140% over the past five years.

Both countries are in the process of discussing and passing new legislation and measures to better regulate these activities from a consumer-protection standpoint. In the U.S., the SAFE Bet Act was introduced and failed to pass in September 2024, and is now awaiting a new version. Brazil's Ministry of Finance recently announced its regulatory agenda for the next two years, under Law 14.790/2023, and the Senate ran a Congressional Inquiry Committee on betting between November 2024 and June 2025 — though its final report was rejected 4 votes to 3, the first time in ten years such a committee's report was rejected.

Existing regulation is built around establishing guidelines for "responsible" use of online gambling and sports betting platforms. It distributes responsibility between operators and users, with measures aimed at protecting users considered "vulnerable" to addiction and other negative consequences. The legislation covers providing information, public education and awareness, restricting access for certain groups (like age limits and a centralized registry of people with gambling problems), regulating marketing strategies, identifying unhealthy gambling behavior, deposit limits, self-exclusion mechanisms, and access to support services for people with gambling addiction.

However well-intentioned, though, the reasoning behind these measures rests on a fundamentally flawed idea about human behavior: that a certain group of people could use these platforms in a healthy way, while only some individuals would develop a problematic relationship with them. So the strategies aim at identification — finding the few people who might have (or already have) a problematic use pattern, and acting on them. The flaw in that reasoning is that when a platform is designed to exploit automatic behavioral mechanisms, the issue isn't reducible to who uses it. While individual differences in susceptibility to addiction and pre-existing mental health conditions certainly exist — which isn't the focus of this piece — negative consequences can extend well beyond that group, and even expand it. This is a system whose very design — which includes not just the platform itself, but how it's embedded in society (who promotes it, how often, and how easily it can be accessed) — produces what I'd call a "power asymmetry." A product that captures attention, manipulates internal reward systems, is stripped of friction, and carries broad social proof in prestigious spaces creates a situation I define as decisional vulnerability. Anyone can become susceptible to misuse under the right conditions. Informing people about "responsible use" isn't just ineffective — it can generate guilt, shame, stigma, and a sense of individual blame for those who fall into harmful patterns. As one example: even though current legislation requires platforms to clearly and transparently disclose the risks of online gambling — and that it isn't an alternative to working — a recent survey by Anbima (2024), the Brazilian capital markets association, found that more people placed at least one online bet (14% of the population) than invested in the stock market (2% of the population). 40% of bettors saw betting as an opportunity to make money in times of need, and 22% consider online betting a form of investment.

A more robust and precise government intervention is needed to prevent this imbalance and protect consumers — not by targeting individual decisions ("i-frame" solutions) or simply restricting access for those already negatively affected, but by changing the platform itself and the systems around it (the "s-frame"), in line with the framework proposed by Chater & Loewenstein (2022). Solutions, then, need to focus on the core automatic behavioral mechanisms at play, protecting them specifically from exploitation by a product. That includes access to the behavior itself, the social value and social proof attached to it — especially through the advertising and marketing industry — as well as the reward schedules and attention-capturing features built into platform design.

On access

Access was the only mechanism found to produce a meaningful impact on behavior change, according to a recent meta-meta-analysis (Albarracín et al., 2024). Making betting platforms available through smartphones stripped the whole process of friction. Apps with user-friendly interfaces make it even easier, letting someone place a bet in just a few clicks. New digital payment methods and easy access to credit reduce the friction of the payment step itself. And if we consider the context in which betting typically happens — usually during sporting events, often at night, when emotions run high, decision-making capacity is depleted, and alcohol consumption is common — the overall situation makes people even more vulnerable. Legislation could follow practices already adopted worldwide for other addictive substances (like alcohol and tobacco) and limit the hours and places where betting is accessible, while adding friction to the process. Examples include: banning smartphone apps, making platforms accessible only via computer; imposing daily limits on time, amount, and number of bets; banning the use of credit cards; and restricting access to business hours.

On social modeling and marketing

Since companies rely heavily on socially prestigious figures — football players, digital influencers — to promote their products, even without explicitly claiming that betting is beneficial (which Brazilian law already prohibits), social modeling, social proof, and image association happen anyway. Today, it's impossible to watch a football match in Brazil without being exposed to betting mentions, a pattern also common in the music entertainment world. As with the tobacco industry, reducing this behavior requires banning marketing strategies that involve socially valued figures — celebrities, influencers, athletes — or the spaces they occupy. Ideally, broad marketing restrictions should be put in place, along with limits on any other positive associations that reinforce the pairing between betting and prestige. In line with this, on May 28, 2025, the Brazilian Senate approved Bill 2,985/2023, which imposes stricter restrictions on fixed-odds betting advertising. Key measures include banning individuals from appearing in ads — including public officials, media figures, athletes, and influencers — with an exception only for athletes retired for more than five years. The bill now moves to a vote in the Chamber of Deputies. More details can be found here.

On platform design

Platform design incorporates mechanisms well recognized in the analysis of behavior — intermittent (variable) rewards, a sense of urgency, prominent buttons, and so on. These tools disproportionately capture attention and drive habit formation and compulsive behavior. Platform design should be built to represent a deliberate choice every single time — something that isn't profitable from the platform's point of view, which is exactly why regulation is necessary. Ways to achieve this include eliminating flashy, colorful buttons, removing sensory rewards (sounds, visual effects, etc.), and inserting a gap between action and reward — which would mean, for example, banning roulette-style games or live, real-time betting during matches.

On minimum age

Although both countries' laws currently prohibit betting by minors, the practice is widespread among them. Sites often require nothing more than checking a box confirming you're not a minor. As mentioned, usage is most frequent among young men. Aggressive advertising on platforms like TikTok — where nearly half of U.S. users are college-age — contributes to this. A UK study found that around 75% of young people aged 18–24 had been exposed to betting ads through social media. In line with this, research by Cetic.br found that between March and September 2025, 53% of children and adolescents had already been exposed to some form of betting advertising. And it doesn't stop at exposure: according to a 2023 report by the National Council on Problem Gambling, roughly 60–80% of high school students reported having gambled in the past year. In Brazil, the National Alcohol and Drug Survey, conducted by the Federal University of São Paulo (Unifesp) in October 2025, found that 10.9% of young people aged 14–18 — more than a million young people — said they had already placed an online bet. Although the official minimum age ranges from 18 to 21 depending on the country or state, the brain's impulse-control circuits don't fully mature until the mid-20s. Legislative adjustments raising the minimum age (to 24–26) should be considered, to keep the most cognitively vulnerable from gaining access. Beyond that, educational, communication, and technological identification measures (facial recognition, location-based blocks on university campuses and high schools) should be adopted to genuinely prevent access by minors, rather than being a mere formality.

While this may look paternalistic at first glance, the goal is to distinguish situations where the real question isn't who decides (government or the individual), but whether the individual decision is actually being made at all. It's about changing the rules of the game in systems that exploit decision-making mechanisms, reducing the odds that any conscious, deliberate thought prevails in the long run. Some of the proposals here aren't new, but placing them within a coherent perspective that ties theory to practice, programmatically, can help build the case for such changes. Worth noting: some bills currently moving through Brazil's Chamber of Deputies incorporate these principles — notably Bill 2478/2026. As behavioral scientists, there's an opportunity to add value by identifying and describing these structural mechanisms, and by offering guidance on precisely how they could be reconfigured, at a moment when society is actively debating them — shifting the behavioral science agenda from implementation into the field of policy formulation as well, in line with the field's most recent thinking.

References

Baker, S., Balthrop, J., Johnson, M. J., Kotter, J. D., & Pisciotta, K. (2024). Gambling Away Stability: Sports Betting’s Impact on Vulnerable Households.

Hollenbeck, B., Larsen, P., & Proserpio, D. (2025). The Financial Consequences of Legalized Sports Gambling.

Matsuzawa, K., & Arnesen, E. (2024). Sports Betting Legalization Amplifies Emotional Cues & Intimate Partner Violence.

Dias, E. R. (2024). Sports Betting and Prevention of Problem Gambling: Proposals for Regulatory Changes in Brazil and the Use of Responsible Gambling Algorithms. Beijing Law Review, 15, 1940–1960.

Yeola, A., et al. (2025). Growing Health Concern Regarding Gambling Addiction in the Age of Sportsbooks. JAMA Internal Medicine.

Chater, N., & Loewenstein, G. (2022). The i-frame and the s-frame: How focusing on individual-level solutions has led behavioral public policy astray. Behavioral and Brain Sciences.

Albarracín, D., Fayaz-Farkhad, B., & Granados Samayoa, J. A. (2024). Determinants of behaviour and their efficacy as targets of behavioural change interventions. Nature Reviews Psychology, 3, 377–392.