Keywords

1 Introduction

Persuasion theory has attracted widespread attention in various fields such as e-commerce, app development, product design, and architectural design [1]. One of the important application areas is intelligent health-care product design. Intelligent health care is an emerging interdisciplinary field combining medical field, network technology, interaction and service design [2,3,4]. It is also an innovation to the clinical treatment with which patients actively cooperate at a specific time and place. Persuasion theory suggests that the user can be induced and persuaded to develop or change behaviors through design intervention, so as to achieve the goal of fitness and develop healthy behaviors [5,6,7].

Persuasive technology is usually defined as a technology to change the attitude or behavior of users through persuasion and social influence rather than coercion [8]. Persuasive theory was first proposed by Fogg, an experimental psychologist at Stanford university. He defined it as any interactive computing system used to form, change or enhance people’s attitudes and behaviors. On the basis of this research, he further integrated computer technology in practical application and put forward Captology theory – “computers as persuasive technology”. As the name implies, Captology focuses on how to make a computer persuasive, thus changing the behavior or attitude of users [9]. It emphasizes the initial purpose of the design and persuades the subjectivity and directness of the result. Compared with human persuasion, the theory features the following advantages: (1) computer persuasion is of longer duration; (2) the computer can carry out anonymous persuasion; (3) the computer can store, acquire and process a large amount of persuasion data; (4) the computer can persuade in various forms; (5) large-scale persuasion can be carried out through computer software; (6) ubiquitous computer technology can be used to persuade people everywhere [10]. From the intention of persuasion, it can be divided into explicit persuasion and implicit persuasion. The former one means that the purpose of designing interactive products is to persuade users to change their attitude and behavior, while the latter means that the design of products is mainly for commercial purposes and persuasion is complementary. In the process of persuading users, computers have three forms of tools, simulations and members of society, that is, the so-called “functional iron triangle”, which can be understood as a conceptual framework describing the three roles that computer technology can play.

Persuasive design is the practice and application of persuasion theory, which is a form of changing the will of the persuaded person through non-mandatory guidance. Persuasive design can also be called “influence design” or “persuasion design”, a method using persuasive techniques to change a user’s attitude or behavior, that is, design with intention of persuasion [11]. Interactive design puts emphasis on the relationship between people and machines. Designers are more concerned with the users’ task execution process and user behaviors. Persuasion design focuses on whether or not the user does something, and what impact the design will have on the user. Therefore, persuasive design pays attention not only to the behavior process of human-computer interaction, but also to the situation in which the interaction occurs, especially the motivation and users’ behavior ability required to facilitate the behavior.

After more than 20 years of development and improvement, the current typical persuasive design model mainly involves four types [12]. The first model refers to the intersection of different disciplines to help designers produce a highly usable method called design with intent (DWI) [13, 14]; the second model is called persuasive systematic design(PSD) that provides systematic analysis and design methods for the persuasive design requirements of software [15]; the third model is FBM based on the understanding of human behaviors [16]; the fourth model is the behavior Wizard model [17]. The PSD model is an interpretation of specific persuasive principles based on Fogg’s theory. FBM theory is the basic support of persuasive principle of PSD model. FBM model believes that a behavior contains three dimensions, namely motivation, ability, and triggers. In order to implement a certain behavior, the individual must have sufficient motivation, ability and triggers to implement this behavior at the same time.

The purpose of this paper is to make an investigation of user’s demand and proposes persuasive design strategies for intelligent health-care product on a basis of persuasion theory. It puts forward the strategies of persuasive design from such major perspectives as target behavior, motivation, ability and triggers: 1. product strategy based on user’s goals. 2. product strategy for improving user’s motivation. 3. product strategy for developing user’s ability. 4. product strategy for enhancing triggers. In this paper, case study method is used to analyze the above design strategies, and the effectiveness of the strategies is verified via real application. To conclude, the research ideas of this paper are laid out as follows. Firstly, based on persuasion theory, the behavior model is studied and the factors of persuasive design are put forward. Secondly, persuasive behavior components and model of persuasive design for health-care product are studied, and persuasive design strategies are proposed in this part. Third, the above design factors and strategies are analyzed in combination with design cases. Finally, this paper will make a summary and point out the future research direction.

2 FBM and Factors of Persuasive Design

2.1 Behavior Model for Persuasive Design

As a tool for analyzing behavioral changes, FBM is designed to help designers understand both the opportunities and obstacles in design. In this way, they can establish a link between target behavior and the design of intelligent health-care product, analyze relevant cases of smart product design, and make persuasive design be used in the construction of a conceptual model of intelligent health-care products. The model should be able to answer what design will improve users’ execution, what type of design or technology can give users encouragement and guidance, as well as what design and technology will motivate users for continued use [18] (Fig. 1).

Fig. 1.
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[Adapted from Fogg [11, 16]]

Behavior model for persuasive design

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2.2 Design Factors

This model concludes four design factors which will search for strategies of intelligent health-care products from four perspectives.

The first factor is target behavior, which is the specific design purpose for the users. The purposes generally include correcting existing unhealthy behaviors, preventing unhealthy behaviors that may occur, motivating users to maintain existing healthy behaviors, raising health awareness, and increasing social connections. Products need to be clear about their emphasis so as to avoid confusion when users choose them. Meanwhile, users may have second thoughts about whether the product can produce target behavior or the completion effect after that. These are all the factors that designers need to take into consideration.

The second factor is motivation. That is, the internal reason why the user is operating or generating usage behavior. Fogg divides motivation into three groups: sensation, anticipation, and social cohesion. Sensation refers to happiness, disappointment, pain, etc. Anticipation stands for the observation of good or bad results for the future: hopeful or fearful; social cohesion refers to social recognition, rejection or social influence.

The third factor is ability. Ability, regarded as the most scarce resource for users, includes various contents such as time, money, physical expenditure, energy consumption, related skills, resilience, etc. All of these, to a certain extent, constitute a hindrance to the user’s inability to accomplish the intended objectives.

The fourth factor is the trigger, which means when both motivation and competence are available, an effective stimulus is needed to trigger the behavior. The triggers are classified by situations: (1) Unable to trigger: either motivation or competence is too low to trigger a behavior. (2) Incentive triggers: for object with lower motivation yet higher ability. For instance, the motivation of the target users is enhanced by positive reactions from other users. (3) Counseling triggers: triggers that help users with lower ability and higher motivation, such as providing health counseling and other scientific methods to improve competence. (4) Indication triggers: triggers working as a reminder or instruction that help users with both stronger motivation and higher ability.

Some people with relatively low motivation and ability may need to combine incentive triggers with counseling triggers. Therefore, in order to trigger effective target behavior, some relevant incentive methods or strategies are needed to enhance the user’s motivation and improve the user’s competence to complete the target behavior, and give appropriate stimulation at right times. Such mathematical models enable behavioral changing theory with computer technology to be better applied into practice. In practical applications, the degree of motivation and ability indicates the probability of behavioral occurrence, while the stimulus, with the help of persuasive strategies, can generate and promote the behaviors.

3 Persuasive Design Strategy for Intelligent Health-Care Products

Persuasive strategy is a specific strategy and method to make persuasive technology into practice and real application. In order to achieve the ultimate goal that persuasive design can change the behaviors or habits of target users, a series of persuasive strategies are needed to embody the model and improve its usability. This paper will propose corresponding design strategies based on factors in FBM model. 1. considered from the perspective of user’s goal (Table 1), the product should have market positioning and provide expected results, etc. 2. considered from the perspective of improving user’s motivation (Table 2), it covers the four phases between the user and the product, which are the processes from impression of the product, product usage, performing the behavior to maintaining the behavior. The contact phase includes visual attraction, function attraction, etc. The using phase includes user experience, social connection, value improvement, etc. The behavior completion phase contains target reward and establishment of new target and so on; The behavior maintenance phase includes emotional maintenance, social maintenance, long-term goal attraction, etc. 3. designed from the perspective of developing user’s ability (Table 3), it concludes content design, behavioral design, and feedback design. 4. from the perspective of improving the effectiveness of triggers (Table 4), it involves visual performance, cultural associations, and feedback timing, etc. is shown in Fig. 2.

Table 1. Persuasive strategies for defining user’s goal
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Table 2. Persuasive strategies for improving user’s motivation
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Table 3. Persuasive strategies for improving user’s ability
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Table 4. Persuasive strategies for activating users
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Fig. 2.
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Persuasive design factors & strategies

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4 Case Study on Persuasive Design of Intelligent Health-Care Products

Recently, as intelligent health-care products have enjoyed wide varieties, and the most popular type is the product that records human bodies, several smart scales have been selected for case analysis.

4.1 Smile Scale

QardioBase scale is elegant in shape and simple in performance. It can measure the proportion of body components, be connected to mobile phones via Bluetooth and WiFi. The necessary data of the body can be displayed on the mobile phone in a graphical form, enabling people to have a quick understanding of their current health condition. Meanwhile, QardioBase scales give users encouragement through the interaction between people and scales, prompting users to enhance their self-confidence and perseverance. When the user stands on a QardioBase scale, the touching feedback system of the scale will gently remind the user that his or her weight has been recorded is shown in Fig. 3.

Fig. 3.
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QardioBase scale smile-face feedback

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The intelligent feedback mechanism of the scale is divided into three types. When the user gradually moves toward the set health goal, the QardioBase scale will give the user a visual smile feedback (Fig. 2). If the weight keep unchanged during a set of time, the expression image on the scale will remain the same. However, when the user’s weight exceeds the set or standard number, the image on scale will become a crying face. Users can grasp their current weight quickly through the changes of these three expressions, and also protect their own weight privacy. What’s more, QardioBase scales also have functions such as target setting and reminding, which can be used by the whole family, thus avoiding the limitation of single user brought by the products. In addition, the reminding function is convenient for users to carry out phased data recording, which improves the user’s motivation and helps them form a long-term using habits.

User’s goals, user’s motivation, user’s ability, and triggers are well designed respectively. Elegant outlook and superior functions can enhance purchase desire; smile-face feedback, family participation and privacy protection during usage are able to improve user’s motivation; simple and indispensable forms and images can save users from too much analysis and improve ability. At last, necessary reminding function can work as a trigger of usage.

4.2 Fitbit Aria Smart Scale Weight

Apart from the interaction between products and users, the scale can also implement the reward function in the weight-loss and fitness process through an additional program in the app. For example, as Fitbit Aria scales in Fig. 3, equipped with a small challenge program, users can compete with friends and families and play various fun games like “Match of the Day” in the process, from which users can win badges, red envelopes or in-kind incentives. At the same time, social participation and user’s stickiness can be strengthened by daily sharing on social media. Users’ determination, enthusiasm and mobility on losing weight can all be enhanced is shown in Fig. 4.

Fig. 4.
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Fitbit Aria scale and challenge program

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For such product, weight control is undoubtedly a factor of target behavior. To improve user’s motivation, the product has been upgraded in terms of its outlook, reward mechanism and deepening social connections. It has gained quite popularity among users especially due to its different reward rules compared with her similar products. The user loyalty maintained by this special reward mechanism will also improve their ability to use the product in long-term run. Due to the observable nature of the real prizes, it constitutes the triggers for continuous use in users’ lives.

4.3 Huawei Smart Scale Weight

Users are expected to get an accurate value when measuring physical data, however, the tilt or unevenness of the site will bring errors in the reading of the scale. Currently, few products on the market solving the problem from this aspect, mostly start from the product itself, which means focusing on addressing functional or outlook problems. But the places for use should not be neglected. is shown in Fig. 5.

Fig. 5.
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Huawei smart scale 360° adjustable scale feet

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Huawei smart scales can also measure the ratio of body composition, have a body composition ratio measurement function, and can display physical changes of the user through various charts in the app of the phone. In addition, it supports the identification of 10 users, and can share measurement data through multiple mainstream social media. This is similar to the previous two scales, but this scale weight has a new highlight in user’s experience. Thanks to the adjustable 360° support frame, it guarantees the usability of the scale in most places, reduces errors during measurement.

This product basically share exact functions and features of the target behavior with the first ones, but in light of improving user’s motivation, apart from providing social connections, simplifying the display mode, etc., it offers more precise measurement and intensifies user’s motivation accordingly. Concerning use’s ability, this design also enhances the adaptability of scales to the environment, eliminating the trouble from seeking for suitable placement, thus user’s ability are improved. Regular timed reminders can be used as a trigger for this type of product.

From the above case analysis, we can see that the application of persuasive-designed products with different factors will affect and guide users’ behavior to different extents. Similar products can also find targets using persuasive design strategies with different factors to overshadow its counterparts. Similarly, due to the difference between target users and positioning of the products, there will be some emphasis on the specific application of the strategy. In the process of subsequent evolution, based on the previous strategies, the product can strengthen and supplement corresponding visual presentation, content structure, behavior flow so as to enhance the user’s behavior motivation and ability to a greater extent, thereby achieving the purpose of persuasion.

5 Conclusion

Even there are plenty of factors impairing health, most of the diseases are caused by users’ own reasons. Therefore, the health self-management of intelligent health-care products is particularly important. To achieve health self-management, a quite effective way is to help users establish healthy behaviors using persuasive technology. As intelligent health-care products become a hot spot of current product design and development, persuasive technology will also be an essential part in the product development process. Hence, it is practical and worthwhile to probe design strategies that can assist designers find enlightenment and come up with solutions in a short time. Certainly, a series of design strategies proposed for intelligent health-care products in this paper are not a complete fixed mechanism. Different products need to be designed with different emphasis depending on the user positioning.