Recently, there has been much interest in so-called “brain training” (BT) applications and games. These programs are typically marketed to consumers as enjoyable, interactive experiences that, if used regularly, are claimed to improve a range of cognitive skills, such as attention, memory, and multitasking ability ( Simons et al., 2016). The potential benefits of such training, if effective, are numerous. For example, training executive function skills such as working memory and task switching could potentially lead to improved outcomes in education, quality of life, and employment for the general population ( Diamond, 2013). In addition, people with cognitive deficits, such as those with intellectual disabilities or age-related cognitive decline, could also benefit from effective cognitive training software ( Robb et al., 2018; Buitenweg et al., 2012).

Research on the effectiveness of various types of cognitive training has found evidence that it can lead to improvements in tasks that bear some resemblance to the training (“near transfer”), but little or no evidence that these improvements transfer to distantly related tasks (“far transfer”) or indeed to everyday life ( Simons et al., 2016; Sala et al., 2019; Aksayli et al., 2019). These findings suggest that theories of transfer that emphasize the importance of overlap between the training and the target skills (e.g., Gobet, 2016; Taatgen, 2013; Oei and Patterson, 2014) may provide the best account of the mechanisms by which cognitive training is effective. Therefore, a detailed theoretical understanding of the overlap between the training and the desired outcome may be an important factor in the design of effective, tailored cognitive training programs in the future (see Smid et al., 2020, for this and other recommendations).

As part of a more comprehensive science of cognitive training, it is also important to investigate the attitudes and habits of the people who will potentially use the training. Individual differences in personality, motivation, expectations etc., are likely to play a role in determining a user’s engagement with a training program ( Smid et al., 2020). Regular engagement is obviously an important factor in any kind of training; however, attrition is a commonly reported problem in trials of cognitive training software ( Corbett et al., 2015; Robb et al., 2019), and at least one commercial BT program ( Cogmed) assigns users a coach to ensure that they regularly engage with the software. Understanding how and why people use cognitive training programs may therefore be an important additional factor in determining their effectiveness.

Previous research has found that participants typically have positive beliefs about the effectiveness of BT. Torous et al. (2016) found positive beliefs about the effectiveness of BT mobile applications in young American consumers, both in participants who had used BT programs and those who had not. Other research found similar results in parents of children with intellectual disabilities (who may benefit from cognitive training): parents believed that BT could benefit their children and expressed positive attitudes towards supporting such training. Again, these attitudes were not related to how much experience the parents had with BT apps or games ( Robb et al., 2018). It has also been shown that people’s expectations about the effectiveness of BT can be influenced by the information they receive about such programs. Rabipour & Davidson (2015) and Rabipour et al. (2018) found that participants’ expectations about the effectiveness of BT at baseline could be subsequently raised or lowered by presenting them with positive or negative messages about BT. Finally, Ng et al. (2020) found that frequency of engagement was only weakly correlated with perceived cognitive benefit for a range of activities, including BT. While this research reveals important information about the attitudes, habits, and expectations of a range of potential consumers of BT, it is primarily focused on Western users. It is widely recognized that much research involving human subjects may be biased towards certain demographics ( Henrich et al., 2010). In the case of understanding attitudes and habits regarding BT, the largest previous study was conducted in the United States ( Torous et al., 2016). To fully understand the attitudes of BT users, it is vital that a global perspective is considered.

Japan represents a large group of potential consumers of cognitive training who may have different habits or attitudes than, for example, those in the US. Previous research has found differences between users from Japan and the US in terms of how they access and use mobile apps ( Lim et al., 2014). Japan also has a developed BT market, with popular BT games having been released in the country for several years ( Fuyuno, 2007; Chancellor & Chatterjee, 2011). Taken together, these points suggest the possibility that attitudes and habits regarding BT may differ between users in Japan and other countries. Therefore, the main purpose of this paper is to provide preliminary data on the habits and attitudes of Japanese people regarding BT apps and games, thus expanding our knowledge of how and why such programs are used around the world and laying the groundwork for future research in this area.

A total of 1000 responses were received. Of these, one response was excluded as the age in years was entered as 336, while six responses were removed as they provided an incorrect answer to the sum of nine and four. A further 175 participants’ responses were removed as they gave inconsistent answers about their history of using BT apps or games. There were four kinds of inconsistency. Firstly, 13 participants answered “yes” to item 8 (“Have you ever used an app or game that claims to increase memory, concentration, attentiveness, or other cognitive abilities? In this survey, we will refer to these as ‘brain training apps/games.’”) but answered “I have never used one” to item 16 (“What is the longest period of time you have used a brain training app/game? If you have never used one, please select ‘I have never used one.’”). Secondly, 11 participants answered “yes” to item 8 but did not enter any brain training apps or games that they had used when asked to do so in item 15. Thirdly, 111 participants answered “no” to item 8, but indicated they had used BT apps or games in item 16 (i.e., they entered a period of time they had used apps or games). Fourthly, 152 participants answered “no” to item 8, but entered apps or games they had used when asked to do so in item 15. Note that some participants' responses were inconsistent in more than one of these ways. With these responses removed, the final sample used for analyses contained responses from 818 participants (524 female, 294 male; mean age 36.1 years; standard deviation 9.5 years). The underlying data can be accessed on the Open Science Framework ( Robb, 2021).

Figure 1 shows the devices and kind of apps owned by participants, divided into seven age categories. In all age groups, at least 70% of participants owned a smartphone, with the highest rate of smartphone ownership (94.12%) in participants aged 30 years and under. Games console ownership was approximately 40% in the 20-29 years, 30-39 years, and 40-49 years categories.

The most common concerns participants had about BT apps and games were the cost of the product, the time required to use them, and a lack of certainty regarding their effectiveness. Most participants did not express concerns about the safety of their health data or whether the apps or games have medical recommendation ( Figure 2).

The most-used training programs were produced by Nintendo and released on the Nintendo DS handheld games console. Over half the participants reported having used Nou wo kitaeru otona no DS training (released in the US as Brain Age: Train Your Brain in Minutes a Day! and in Europe as Dr. Kawashima’s Brain Training: How Old Is Your Brain?) and just under a quarter of participants reported using the follow-up game ( Motto nou wo kitaeru otona no DS training; US: Brain Age 2: More Training in Minutes a Day! Europe: More Brain Training from Dr. Kawashima: How Old Is Your Brain?). Of the remaining programs, all but one were used by fewer than 10% of participants. Only 19 participants (2.32%) reported having used Lumosity ( Figure 3).

Participants indicated positive perceptions of BT apps and games, believing that they could improve thinking ability (79.58%), attention (66.26%), memory (78.61%), and mood (73.35%). Phi-coefficients were calculated for all combinations of the binary variables (i.e., yes/no questions) regarding participants’ views about whether BT could improve thinking ability, attention, memory, and mood, as well as the binary variables regarding whether they had used BT, and if they thought BT had negative side effects. There were weak to moderate positive correlations between (1) thinking ability and attention (ϕ = 0.376, p < 0.001), (2) thinking ability and memory (ϕ = 0.453, p < 0.001), and (3) attention and memory (ϕ = 0.378, p < 0.001) ( Table 1) (see Akoglu, 2018, and Schober et al., 2018, for discussion of interpretation of strength of correlations).

Following Torous et al. (2016), a score was calculated for each participant measuring how positively they felt about BT. Participants were given one point for each positive answer to the four questions about whether they thought BT improved thinking ability, attention, memory, and mood, and one point for a negative answer to the question about whether they thought BT apps and games have negative side effects. The maximum score of five indicated a participant thought BT improved all four factors and had no side effects, while the minimum score of zero indicated a participant thought BT did not improve any of the four factors and had negative side effects. This score was significantly higher among respondents who indicated that they had used BT apps or games (Mann-Whitney U test, U = 37757, p < 0.001); the rank biserial correlation was -0.213, indicating a weak effect size. This score showed negligible or weak correlations (Pearson correlation) with both the total number of apps/games a participant had used (Pearson’s r = 0.163, p < 0.001) and the duration they had used BT apps/games (Pearson’s r = 0.237, p < 0.001) ( Table 2).

Finally, gender differences were also examined, as suggested by reviewer 1. There were significant differences between males and females in terms of smartphone ownership (females more likely to own), games console ownership (males more likely to own) and the belief that BT apps/games have negative side effects (females more likely to think so). Phi-coefficients showed that these associations were all weak or negligible (ϕ ranged from 0.097 to 0.12). These results are shown in Figure 4.

The results of the present study suggest that a high rate of Japanese consumers may have positive perceptions of the potential benefits of BT apps and games, comparable to or (in the case of positive effects on mood) higher than the rate in US consumers ( Torous et al., 2016). While there were correlations between positive perceptions about the effects of BT on specific cognitive factors (thinking ability and attention, thinking ability and memory, and attention and memory), these were weaker than those found in US consumers ( Torous et al., 2016). Similarly to Torous et al.’s (2016) findings in US consumers, most participants in the present study did not indicate concerns about clinical recommendations, privacy of health data, or negative side effects, when considering BT games. Rather, the cost of apps/games, the time involved, and uncertainty about their effectiveness were the main concerns in the present sample. While this study only presents preliminary findings, it is interesting to note the similarities with the US participants in the previous study. Previously, it was shown that there were only minor demographic differences (in terms of gender and level of education) in beliefs about benefits of BT ( Ng et al., 2020). It may be that there are similarly minor differences between people from different socio-cultural backgrounds, although further research to investigation this specific hypothesis would be required.

Lumosity, which was used by 70% of US consumers in the previous study by Torous et al. (2016) was only used by 2.3% of the Japanese participants. This large difference in the number of participants using Lumosity may be partly explained by the fact that the app was only released in Japanese in December 2014. In the Japanese paticipants surveyed here, the most popular brain training apps were games made by Nintendo for the Handheld Nintendo DS console. However, since the previous study ( Torous et al., 2016) only focused on smartphone apps, it does not provide any information about how widely used Nintendo BT games are in US consumers. Nintendo BT games are popular globally, however: Brain Age: Train Your Brain in Minutes a Day! (the most used game among Japanese participants in the present study) was among the 10 best-selling video games of 2006 in the US. It is therefore likely that many of the participants in Torous et al.’s (2016) study also had experience of using this BT game.

The results presented here also support previous findings that people’s perceptions of the positive effects of BT are not strongly related to their experience of using BT. Torous et al. (2016) found that US consumers’ positive beliefs about BT were only weakly correlated with the number of BT apps they had used. Similarly, Rabipour et al. (2018) found that people with experience of BT had similar expectations about its effectiveness to people with no experience. In other research, Robb et al. (2018) found that parents of children with intellectual disabilities had positive beliefs and attitudes regarding BT and had high intentions to support the use of BT by their children, despite the fact that the sample had very little experience with BT programs. Taken together, these results present mounting evidence that experience of using BT is not strongly associated with positive beliefs about the effectiveness of BT. The fact that participants in both the present and previous studies ( Rabipour & Davidson, 2015; Torous et al., 2016, Rabipour et al., 2018, Robb et al., 2018) have very positive beliefs about the effectiveness of brain training (whether or not they have actual experience of using BT), combined with the lack of evidence that BT is actually effective ( Simons et al., 2016; Sala et al., 2019; Aksayli et al., 2019), illustrates the importance of investigating the role of psychological factors such as motivation, effects of being observed during training and testing, and placebo effects in BT research. It has been shown that users' perceptions about BT can be relatively easily influenced by biased messages regarding their effectiveness ( Rabipour and Davidson, 2015; Rabipour et al., 2018), and placebo effects have been found in previous BT research ( Boot et al., 2013; Foroughi et al., 2016). Future trials of BT programs would benefit from accounting for such potential confounding factors.

To facilitate a direct comparison between Japanese and American users of BT, this study used a direct translation of the questionnaire developed by Torous et al. (2016). In this questionnaire, the items referring to participants’ positive and negative beliefs about BT (e.g., “Do you think brain training apps and games can improve memory?”) were phrased as questions requiring yes/no answers. However, in retrospect, it may have been more informative to adapt the questionnaire to have Likert-style responses. This would still have allowed some comparison with previous research but could have also facilitated more nuanced analysis of the results. This represents the major limitation with the current study.

While the use of crowdsourcing platforms such as CrowdWorks to recruit participants is becoming more common in recent research, there remain some potential limitations associated with this approach. Firstly, it is recognized that crowdsourced participants may not always be representative of the population of interest ( Stewart et al., 2017). In the present study, this issue is most obvious when considering the ages of the participants: in 2015, 26.6% of the Japanese population were over 65 ( Statistics Bureau of Japan, n.d.), whereas in the sample analyzed here, only 9 of 818 participants were over 60. Given that BT is often considered as a potential intervention for people with age-related cognitive decline ( Buitenweg et al., 2012), the habits and attitudes of this demographic are clearly important. Secondly, it may be suggested that data collected from crowdsourcing platforms is of low quality (e.g., due to participants answering questions without fully reading or considering them). However, previous research has found data collected via the crowdsourcing platform Amazon Mechanical Turk is of comparable quality to other methods ( Kees et al., 2017). In the present study, several indicators were used to identify potentially automated or low effort responses (see section Participants and Procedure). A total of 182 responses (18.2%) were removed before analysis, which is comparable to the rate of 14% automated and low effort responses found in a study of Amazon Mechanical Turk workers by Buchanan & Scofield (2018).

A final limitation may arise from the translation and adaptation of the original questionnaire used by Torous et al. (2016). Although the translation process involved three independent translators and the production of a back-translation which was compared with the original questionnaire, it remains possible that the meaning of some items was altered in a way that affected the results.

Due to the low number of participants over 60 years old, the present study cannot provide any reliable information on the attitudes and habits regarding BT in the elderly population in Japan. Future research investigating this topic would be important. Future research could also benefit from using Likert-style items, as discussed in the section Limitations. Further research will also be required to understand more completely the factors that influence people’s attitudes towards BT, and the role of psychological confounders such as placebo effects in BT research. Finally, one important finding of the present study is the popularity of BT games produced by Nintendo, emphasizing the importance of games consoles in the BT market, at least in Japan. Since the previous major study of BT habits in western users only focused on smartphone applications ( Torous et al., 2016), future research should investigate if BT programs on games consoles, such those produced by Nintendo, are as widely used in countries other than Japan.

This preliminary study contributes to a growing literature investigating the expectations, attitudes, and habits of potential users of brain training applications and games. There are two main findings. Firstly, similarly to previous research conducted in the US, Japanese consumers have positive beliefs about brain training which do not seem to be strongly associated with the amount of experience they have using such programs. Secondly, the most widely used brain training software among Japanese participants are two games made by Nintendo and played on the handheld Nintendo DS console.

No competing interests were disclosed.