A literature search was performed on August 3, 2023, in nine electronic databases via the EBSCOhost platform: APA PsycINFO, Academic Search Complete, APA PsycExtra, Business Source Complete, CINAHL Plus with Full Text, EconLit with Full Text, MEDLINE with Full Text, Psychology and Behavioral Sciences Research Topic, and SocINDEX with Full Text. The search strategy included terminology from the concepts of both “nudge” and “gambling” (see Figure 1) and was developed with the help and support of an academic health librarian from the University of Sherbrooke. In addition, the terms “nudge” and “gambling” were searched on Google Scholar and the references of all selected articles were closely examined.

The following inclusion criteria were applied during article selection for this scoping review: (1) articles are directly about the concept of nudge and gambling, (2) articles are published in a peer-reviewed journal, and (3) articles are in English.

The sorting of the resulting 978 articles began with the withdrawal of duplicates, leading M-EF to screen the titles and abstracts of 931 articles. M-EF then reviewed the remaining 46 full-text articles and classified each according to our level of certainty about its relevance for our scoping review and its accordance with the inclusion criteria. During the selection process, disagreements were discussed by all team members. M-EF, SA-C, and MB debated the inclusion or exclusion of the last four articles under evaluation. This concluded the final selection of the six articles included in our study. All team members approved the final selection (Figure 2).

M-EF conducted the data extraction of the following characteristics for the six articles: authors’ names, year, title, country, objective, methodology, population studied, and main conclusions of the article (see Table 1). Table 1 was revised by SA-C and MB. The data collected in the six articles were grouped by themes and are presented according to the narrative synthesis approach, which consists of concise “findings from multiple studies that rely primarily on the use of words and text to summarize and explain the findings” (21).

All selected articles were published between 2018 and 2021, and four of the six were from Australia (11, 15, 19, 20). The other two articles were from Canada (17) and the United Kingdom (18).

There was wide variety within our selection of articles, comprising a theoretical article (11), a commentary (17), an editorial (18), a perspective (15), a letter to the editor (19), and one original research study (20) (see Table 1).

Regarding the methodology and the characteristics of the populations studied, only the original research study provided such information (20). As this is mixed-method research, it adopts a mixed quantitative and qualitative design. The data analyzed came mostly from observations performed in sports bars, as well as interviews with customers. The mean age of the studied group was 33.3 years old, and the sample was composed principally of men (70%).

The article by Gainsbury et al. (11) explains behavioral economics in the most detail. Indeed, the authors mention that, according to behavioral economics, individuals tend to use shortcuts known as heuristics in complex and uncertain situations. Heuristics enable individuals to make prompt decisions with less mental effort. However, this can also generate unconscious errors, called biases. The authors also report that many of these heuristics and biases are exploited in gambling. Two articles in our selection (11, 18) explicitly link gambling features to heuristics and/or biases, giving examples as to how gambling games are conceptualized with strategies such as “losses disguised as wins” or “near-misses.” These strategies can take the form, for example, of a slot machine displaying a congratulatory message for a win that is worth less than the bet (11). Murch and Clark (17) also note that “losses disguised as wins” harm the decision-making process for people who practice gambling. Two articles in our study selection also briefly mention the field of behavioral science (15, 19), while one makes no mention of it (20).

All six selected articles define the nudge concept as deriving from choice architecture (see Table 1). As mentioned by Gainsbury et al. (11), nudges “involve making subtle alterations in the choice environment to encourage behavior change.” Unlike dark nudges, nudges aim to prompt people into making healthier choices (17, 19, 20). Nudges are also characterized by not restricting people, who remain free to choose other options (15, 17).

In the gambling context, the authors mention that nudges could be used to lead individuals to adopt healthier (15) and safer (19) gambling practices. The effectiveness of nudges in gambling lies in their cost-effectiveness and subtlety (11). Nudges in gambling are most effective when they resonate with individuals’ own understanding of what is important (11).

As seen in Table 2, some examples of nudges in gambling involve the use of normative feedback to compare one’s gambling behaviors with that of others. Such feedback could also include incentives (such as smiley faces, words of encouragement, etc.), dynamic messages during gambling (“Do you need to take a break?”) (11), or a monthly summary of all gambling activities (11). Murch and Clark (17) suggest that it would be beneficial to use nudge theory to modify slot machines, such as by suppressing the sound normally made for “losses disguised as wins.”

Newall and Rockloff identify a nuance about nudges in gambling (19). While they agree that nudges could prompt safely gambling practices, they consider that it would be more urgent to reduce the dark nudges present in gambling environments.

Finally, while all of the articles discussed nudges, two of them defined the concept of nudges only briefly, after which they focused on dark nudges (18, 20).

In four of the six selected articles, the authors explicitly question the dark nudges features of gambling games, as these impair the decision-making processes of those who gamble, thereby taking advantage of their biases (see Table 2) (17–20).

Murch and Clark (17) consider “losses disguised as wins” to be dark nudges. Newall and Rockloff (19) also give examples of these features in gambling, such as suggesting high deposit limits. Pennay et al. (20) observed elements in sports bars that could also be considered dark nudges, such as the “visibility, lighting, scale and proximity to the entrance” of the electronic gaming machines. In addition, Gainsbury et al. (15) mention that some features in gambling, such as “infinity scrolling,” nudge users into “continued gambling.” These words dovetail with the concept of dark nudges, even though the term itself is not used by the authors.

Many stakeholders are involved in gambling, and some of the articles in our selection discuss their roles (15, 18, 19), with some reporting on the contradictions or conflicts of interest that exist among them (11, 15). Two articles—Gainsbury et al. (11, 15) and Newall (18)—report that stakeholders should work together to reduce gambling harms. More precisely, Gainsbury et al. (15) provide an in-depth description of the roles played by individual users, community groups, gambling industry operators, government actors and regulators, financial institutions, and researchers to establish safer online gambling. Newall (18) discusses briefly the dynamics between stakeholders and notes that “gamblers, gambling firms, regulators and researchers” are all implicated in the current state of the gambling environment.

Gainsbury et al. (11) and Newall (18) note that while gambling is a source of government income, it comes with a big societal cost, and this cost causes a conflict of interest (11). Newall (18) adds that the presence of dark nudges in gambling is a mark of contradiction from gambling officials, since “the gambling industry claims to support responsible gambling” (18).

All of the articles in our selection advise that actions be taken to encourage responsible gambling or to reduce gambling harms. In accord with the fact that their articles mostly address dark nudges, the recommendations of Newall (18) and Pennay et al. (20) do not include nudges. However, according to Newall (18), researchers in the field of gambling should pay close attention to electronic gambling machines because they constitute a large part of “gambling’s public health costs.” He also highlights the importance of informing people who gamble about the real odds of winning. For their part, and in concordance with the subject of their article, Pennay et al. (20) suggest that researchers should study various populations and sports bar environments to guide forthcoming public health interventions.

The other four selected articles suggest future uses of nudges in gambling. Gainsbury et al. (11, 15) highlight the role of researchers who study nudges in gambling. The 2018 article mentions that researchers should complete more studies to evaluate nudges in gambling and the effectiveness of interventions on different groups (11). The 2020 article suggests that researchers identify and investigate persuasive designs in gambling and nudges (15). Also, Murch and Clark (17) consider that nudges can establish a bridge between research findings and gambling policies. Gainsbury et al. (15) recommend that operators in the gambling industry detect people who gamble at “moderate-risk” and then send them personalized dynamic messages “about consumer protection tools.” According to Newall and Rockloff (19), operators could also redesign the deposit limit tool “by removing the dropdown list’s suggested limits and by getting gamblers to input their own limits.”

This scoping review draws a systematic portrait of, and synthetizes the literature regarding, nudges and gambling. It also distinguishes terminology within nudge theory (i.e., nudge, sludge, dark nudge) and highlights the need for uniformity in the vocabulary of this emerging field. However, as this scoping review included only published articles in peer-reviewed journals, gray literature was not included. Furthermore, only articles written in English were included, which may have led to an underestimation of the number of articles linking nudges and gambling.