Discussion Papers In Economics
And Business
Short-term responses to nudge-based messages forpreventing the spread of COVID-19 infection:
Intention, behavior, and life satisfaction
Shusaku Sasaki, Hirofumi Kurokawa, Fumio Ohtake

Discussion Paper 20-11

August2020

Graduate School of Economics
Osaka University, Toyonaka, Osaka 560-0043, JAPANShort-term responses to nudge-based messages for preventing
the spread of COVID-19 infection:
Intention, behavior, and life satisfaction
Shusaku Sasaki* Hirofumi Kurokawa† Fumio Ohtake‡

Abstract:
To control and slow down the spread of COVID-19, policymakers and practitioners are employing
messages with elements and wording based on nudges to encourage people’s voluntary behaviorsof contact avoidance and infection prevention. However, although existing studies have found thatnudge-based messages strengthen their intention to take the behaviors, it is not known whether themessages really promote their actual performance. In the end of April 2020, we conducted a survey
experiment on a nationwide sample of Japan through the internet, where we randomly provided tothem one of five different nudge-based messages and a message without nudges, and subsequently
ascertained their intention to take the contact avoidance and infection prevention behaviors. In the
beginning of the following month, May, we further conducted a follow-up survey to determine
their actual behavioral changes. The empirical analysis with 5,225 respondents found that only the“Altruistic Message” emphasizing that their behavioral adherence would protect the lives of people
close to them reinforced their intentions and also could promote some actual behaviors. However,the similar behavioral changes were not observed for the messages which contained an altruistic
element but emphasized it in a loss-frame, or described it as protecting both of their own and others’
lives. The message emphasizing only their own benefit were found to have the adverse effect ofimpeding their intention and behavior. Further analysis revealed that even the gain-framed“Altruistic Message” with the promotional consequences had side effects of deteriorating thequality of sleep and diet and life satisfaction. When employing nudge-based messages as acountermeasure for COVID-19, the policymakers and practitioners need to carefully scrutinize theelements and wording of the messages while considering their potential adverse effects and side
effects.
Keywords: Infectious diseases, nudge, behavioral economics, altruism, physical distanceJEL codes: C93, D01, D91, I12,*

Corresponding author; Faculty of Economics, Tohoku Gakuin University,

E-mail: ssasaki.econ@mail.tohoku-gakuin.ac.jp†

School of Economics and Management, University of Hyogo, E-mail: kurokawa@em.u-hyogo.ac.jp‡

Graduate School of Economics, Osaka University, E-mail: ohtake@econ.osaka-u.ac.jp

This research is financially supported by the Japan Society for the Promotion of Science [JSPS Grant
Numbers: 19K13722 (S., Sasaki), 19K13730 (H., Kurokawa), and (A) 20H00078 (F., Ohtake)].

The outbreak of COVID-19 is posing a major health threat all over the world. Until effective
therapeutic drugs and vaccines are developed, it is crucial to slow down the further spread ofnovel coronavirus infections. Practicing social distancing, frequent and proper hand washing,disinfecting hands, reducing contact with other people, and wearing a mask have been reported
to be effective in preventing the spread of infection (WHO, 2020). As such, there has been risingdemand for information about what types of intervention can be performed to encourage
individuals to take such preventive actions.

Urban lockdowns have been enforced in most countries, restricting individuals from going out
and operating businesses. Governments’ aim with such measures was to reduce the chance ofcontact with others. Meanwhile, some countries, including Japan, have been unable to enforce
compulsory interventions such as the lockdowns under their current laws. Instead, the countries
have implemented non-compulsory interventions (e.g., requests/guidance), urging people tovoluntarily take preventive actions. Moreover, the number of the countries that have now lifted
the previously implemented lockdowns is increasing. Also in such countries, non-compulsory
interventions are expected to encourage voluntary preventive behaviors while simultaneously
resuming economic activity. Therefore, there is currently a particular need for insight into which
non-compulsory intervention effectively promotes voluntary infection prevention behaviors inindividuals.

“Nudge” is an intervention that makes use of behavioral economics and is generally known as amethod to guide people’s behavior toward a socially desirable direction while maintaining their1

freedom of choice (Thaler & Sunstein, 2009). It has been reported that nudge-based interventions
can promote positive behaviors in medical and health fields (Patel et al., 2018; Vallgårda, 2012).

In this COVID-19 pandemic, policymakers and medical practitioners have developed a message
that contains elements of nudges and used such a nudge-based message to encourage people totake the behaviors of contact avoidance and infection prevention. In particular, we often foundaltruistic messages emphasizing that taking such the behaviors will save the lives of others(British Broadcasting Corporation News, 2020; New Zealand Police, 2020).

Concurrently, an increasing number of studies have experimentally evaluated the impacts ofnudge-based messages on people’s intentions and actual behaviors to prevent the spread of
COVID-19 infection. For example, Jordan et al. (2020) found that the message that emphasizes
the public interest (“don’t spread it”) was more effective in strengthening intention to takemeasures to prevent COVID-19 than the message that emphasizes an individual’s interest (“don’t
get it”). Lunn et al. (2020) found that the message emphasizing the possibility that you could
cause the exponential spread of infection to others was more effective in fostering intention totake preventive actions than the message that instructs people to maintain social distance of two
meters. Utych and Fowler (2020) found that people residing in an outbreak region were likely torecognize the risks of COVID-19, when they received the message emphasizing how COVID-19
poses a danger both to the elderly and young people. In addition, Barai et al. (2020) reported that
their nudge-based messages did not have no additional stimulatory effect among people who
were already taking sufficient preventive actions. Furthermore, Falco and Zaccagni (2020) foundthat the message emphasizing how taking preventive actions benefits “you and your family”
2increased intention to engage in such actions, although they had no observable effect on theiractual behaviors.

Existing studies suggest that altruistic messages making people consider the benefits and risks toothers strengthen intention to take preventive behaviors. However, little is currently known about
which message promotes their actual performance of the behaviors.

This study conducted the following online experiment for residents throughout Japan to clarify
the effect of nudge-based messages on their intention to take actions to prevent the spread of
COVID-19 infection, actual behavior, and life satisfaction. In the experiment, after firstpresenting a nudge-based message and asking the subjects about their intention to avoid contact
with others and to take preventive actions, we conducted a follow-up survey around one week
later to determine whether the actual action had been performed. By using these answers, we willassess the influence of nudge-based messages on actual behavior as well as intention.
Additionally, the experiment and its follow-up survey captured subjects’ degree of satisfaction invarious daily situations, including overall lifestyle contentment, how leisure time is spent, family
relationships, etc. The answers will enable us to verify the effectiveness of nudge-based
messages on life satisfaction and clarify possible side effects.

Recent studies in behavioral economics suggest that it is important to develop nudge-based
interventions which contribute to the achievement of social goals while not worsening
individuals’ welfare (Allcott & Kessler, 2019). The behavioral changes expected in this study are
beneficial to our society in terms of preventing the spread of infection and at the same time to3

individuals in terms of preventing their own infection. However, the changes also include thepotential to limit or alter their lifestyles, which could lead to their disutility and may appear informs of reduced income, unemployment, and poor health in the long term. Since this study has
followed respondents only for a short period of time, we will use multiple measures of life
satisfaction as proxies of individuals’ welfare and empirically consider the potential for nudgebased messages to deteriorate it.

This study utilized five nudge-based messages: (1: Altruistic Message): By avoiding contact withothers and taking action to prevent infection, you can protect the lives of people close to you; (2:Loss-framed Altruistic Message): If you do not take such measures, you will expose people close
to you to danger; (3: Selfish message): By taking such measures, you can protect your own life;(4: Altruistic and Selfish Message): By taking such measures, you can protect the lives ofyourself and people close to you; and (5: Simple Message): Stay home.

Our nudge-based messages have three main characteristics. First, we compared the message
which emphasizes the interests of others (1) with that which emphasizes self-interest (3).
Previous behavioral economics studies have found that many people act not only in their own
interest but also in the interests of others, such as charitable giving (Andreoni ,1990) and othercooperative behaviors (Fehr & Gachter, 2000). Some studies have shown that messages
emphasizing social interests enhance people’s willingness to receive influenza vaccines (Betsch
et al.. 2017) and to take actions to prevent the spread of COVID-19 (Jordan et al., 2020).

4

The message (4) emphasizes both sets of interest. We first expect that emphasizing both willfurther strengthen the people’s intention and promote their actual behavior. However, in people
attempting to behave for the interests of others, promoting both sets of interest may
simultaneously “crowd out” their altruistic motivation and thus impeding their actions (Gneezy& Rustichini, 2000).

Second, we compared the message (1), which emphasizes the interests of others by framing interms of “gain” and the message (2), which emphasizes by framing in terms of “loss.” Theprospect theory of Tversky and Kahneman (1981) states that people’s choices can depend onwhether they are framed in terms of “gain” or “loss,” even if their substance is essentially thesame. In health and medical fields, the “gain” frame has been found to be effective for the
behaviors aimed at preventing the onset of diseases, including the use of sunscreen (Detweiler etal., 1999) and quitting smoking (Toll et al., 2007). Meanwhile, for promoting disease-discovery
behaviors including undergoing a mammography (Schneider et al., 2001), “loss” frames havebeen shown to be more effective (Rothman et al., 2006).

Third, we compared the message (5) simply urging a specific action. It is generally known that
simple expressions are easier to understand (Sunstein 2014). The way to simplify actionable
instructions has long been the subject of debate in public health (Zarcadoolas, 2011). Our simple
message “stay home” was also used through social media and online campaigns worldwide.

5

Experimental Design
Overview of ExperimentThis study consisted of two parts; the first was an experiment for intervention that displayed
nudge-based messages, while the second was the follow up. We commissioned MyVoiceComm
Co., Ltd., which is a company engaged in conducting online surveys, to conduct our experimentand subsequent survey. Respondents were extracted from their monitors, who reside throughout
Japan, such that the respondents’ gender and age (20–69 years) ratios would be equal. The firstexperiment was conducted over a 3-day period from April 28–30, 2020, and 6,050 samples andtheir response data were collected. The follow-up survey was conducted during a 5-day period
from May 8–12, 2020, and 5,664 samples and response data were collected. We used for the
study analysis 5,225 respondents who participated in both and provide valid answers.

The first experiment captured respondents’ personal attributes, including gender, age, andaddress, as well as frequency of contact avoidance and infection prevention behaviors for the
week prior to the experiment and their level of life satisfaction. Next, we randomly assigned the
respondents to one of the control group and five nudge-based message groups, and displayed adifferent message to each group. Then, we asked their intention to take the contact avoidance andinfection prevention behaviors during the following week. Finally, we asked them questions
about their socio-economic attributes, which are not affected by random assignment, including
educational background, family structure, and household income.

The follow-up survey again presented questions concerning frequency of contact avoidance andinfection prevention behaviors during the past one week and the degree of life satisfaction.
6

We conducted this experiment and survey from the end of April to the beginning of May, 2020,
when the level of awareness regarding the spread of COVID-19 infection reached its peak inJapan (Figure 1). Furthermore, this period (referred to as “Golden Week” in Japan) contains
several holidays in close succession, and every year many people travel to tourist spots
throughout Japan. In the midst of the pandemic, it was extremely important to control people’s
movements as much as possible during the holiday week, promote avoidance of close contact,
and take thorough actions to prevent the further spread of infection.

We started this study after obtaining ethics committee approval from Graduate School of
Economics, Osaka University.

7

Figure 1 Timeline of the Experiment and the COVID-19 Related Policy in Japan

Notes: A red solid (dash) line shows the start (end) point of the first experiment. A blue solid(dash) line shows the start (end) point of the follow-up survey. Grey shade (April 29-May 6)
shows “Golden Week” (GW) which contains several holidays in close succession. Japanese
government declared the state of emergency in 7 prefectures (Tokyo, Saitama, Chiba, Kanagawa,
Osaka, Hyogo, Fukuoka) on April 7 and the other prefectures on April 16. Japanese government
lifted the state of emergency in 39 prefectures on May 14 and 3 prefectures (Kyoto, Osaka,
Hyogo) on May 21 and the other prefectures (Tokyo, Saitama, Chiba, Kanagawa, Hokkaido) on
May 25.

8

Nudge-based Messages
During the intervention, we first provided general information about COVID-19 (declaration of
emergency, mortality rate, transmission routes, etc.) to all the groups (see the actual screen in
Figure A1 of the Appendix). After that, we displayed a different message to each group. In thecontrol group, we introduced three effective measures to prevent infection, as follows:“To prevent infection,

・Reducing contact with others
・Avoiding the “3 Cs” of closed spaces, crowded spaces, and close contact
・Practicing proper hand washing and wearing a mask
are effective.”

In the intervention groups, one of the five nudge-based messages was randomly displayed inaddition to the introduction. The specific messages were as follows (see the actual screens inFigures A2-A7 of the Appendix):(1: Altruistic Message)
By refraining from going out, avoiding the “3 Cs,” washing your hands, and wearing amask,
you can protect the lives of people close to you.

9

(2: Loss-framed Altruistic Message)
By going out, not avoiding the “3 Cs,” and not washing your hands or wearing a mask,
you will put the lives of people close to you at risk.

(3: Selfish Message)
By refraining from going out, avoiding the “3 Cs,” washing your hands, and wearing amask,
you can protect your own life.

(4: Altruistic and Selfish Message)
By refraining from going out, avoiding the “3 Cs,” washing your hands, and wearing amask,
you can protect the lives of yourself and people close to you.

(5: Simple Message)
Stay home.
You can protect the lives of people close to you.

We confirmed that socio-economic attributes were well-balanced across the groups (see Table
A1 of the Appendix).

10Outcome Measures
This study used three types of indicator as outcome variables (Table 1). The first was contact
behaviors with others by going out. For the following ten types of behaviors, in the firstexperiment, we measured the frequency of respondents’ actual behavior during the previous one
week before the intervention (“0: never” to “7: almost every day”) and the strength of theirintention to avoid such behavior after the intervention (“0: no intention of stopping” to “7: willdefinitely stop”), while the follow-up survey captured the frequency of their actual behaviors
after the intervention on the same scale as the first.

The second indicator was other infection prevention behaviors. For the following 15 types of
behaviors, in the first experiment, we assessed the frequency of respondents’ actual behavior
before the intervention (“0: never” to “7: almost every day”) and the strength of their intention totake such behavior after the intervention (“0: no intention of doing” to “7: will definitely do”),
while the subsequent survey captured the frequency of their actual behaviors after theintervention on the same scale as the first. We created the first and second indicators, which werebased on the study of Jordan et al. (2020) and Muto et al. (2020) and fine-tuned, reflecting
Japan’s situations.

The third indicator was life satisfaction. We used a 5-point scale (responses ranging from “1:dissatisfied” to “5: satisfied”) calibrated to seven categories of items, including general lifestyle,residential area, leisure time, current household finance status, family relationship, friendships,
and work.

11

Table 1 Outcome Measures
Frequency prior to the intervention
Panel A. Contact behaviors with others by going out(“0: never” to “7: almost every day”)
Mean

S.D.

0

7

1

Go to a tavern or bar

0.113

0.662

96.37%

0.15%

2

Go to a restaurant

0.288

0.956

88.18%

0.36%

3

Go to a cafe

0.181

0.812

93.21%

0.34%

4

Go to a supermarket or grocery store

2.541

1.881

16.99%

4.26%

5

Go to a gym

0.117

0.697

96.61%

0.19%

6

Go to work

2.285

2.651

51.08%

10.33%

7

Travel on public transportation such as trains and buses

0.859

1.808

76.18%

2.53%

8

Travel by plane

0.099

0.640

96.99%

0.27%

9Participate in small gatherings and events (excluding online ones)

0.203

0.853

92.50%

0.40%

10 Participate in large gatherings and events (excluding online ones)

0.109

0.664

96.71%

0.25%

Frequency prior to the intervention(“0: never” to “7: almost every day”)

Panel B. Infection prevention behaviors

Mean
12

S.D.

0

7

1
2

When you need to cough or sneeze, place a mask or handkerchief overyour mouth (“cough etiquette”)
Practice gargling and frequent hand washing and disinfection of hands
and fingers with alcohol

5.329

2.442

11.15%

57.75%

6.074

1.702

2.42%

68.47%

3

Try to avoid touching your face

4.101

2.418

14.29%

25.77%

4

Always wear a mask when talking

5.109

2.322

8.94%

46.81%

5

Avoid shaking hands

5.612

2.400

11.76%

67.67%

6

Talk with others via phone or video call whenever possible

4.116

2.805

23.43%

36.29%

5.095

2.204

6.76%

43.16%

4.558

2.564

14.79%

36.99%

3.841

2.983

30.83%

36.16%

10 Use delivery or mail-order services for larger purchases

3.712

2.884

28.92%

31.63%

11 Always wear a mask when going out

5.905

2.040

5.46%

69.97%

12 Avoid going out if you feel unwell

5.023

2.684

17.26%

55.17%

13 Try to stay home as much as possible even if you are not ill

5.805

1.930

4.78%

61.14%

14 Get plenty of rest and sleep

5.613

1.842

2.63%

52.03%

15 Eat nutritious foods

4.802

2.038

5.69%

31.97%

7
8
9

Designate one person to do the shopping or go out in a small group andduring times when stores are not crowded
Use cashless payment methods (credit cards, electronic money, etc.)
instead of cash
Use take-out or home delivery services instead of going to restaurants

13Degree prior to the intervention(1: dissatisfied” to “5: satisfied)Panel C. Life satisfaction
Mean

S.D.

1

5

1

General lifestyle

2.974

1.131

12.90%

9.02%

2

Residential area

3.191

1.046

7.99%

10.37%

3

Leisure time

3.028

1.107

11.36%

9.25%

4

Current household finance status

2.762

1.160

17.81%

7.76%

5

Family relationship

3.374

1.095

7.06%

17.11%

6

Friendship

3.267

1.006

6.47%

11.93%

7

Work

2.877

1.075

13.61%

7.46%

Notes: We used the data of 5,225 respondents and calculate the descriptive statistics.

14

Table 1 also shows the level of each indicator prior to the intervention. We found thatapproximately 90% of respondents had not visited a bar, restaurant, cafe, or gym during
one week prior to the intervention, and many had already taken some actions to avoid
close contact. This study’s situation is similar to that of Barai et al. (2020).

Results
Intention
Using only the data of the first experiment, we examined respondents’ intention to takecontact avoidance and infection prevention behaviors immediately after seeing nudgebased messages. We used for analysis an ordinary least-squares regression.1

Panel A in Figure 2 shows estimated parameters of receiving a nudge-based message,
with 10 types of intention to avoid contact with others by going out as dependent
variables. We found significant and promotional effects only for the Altruistic Message(although at a 10 percent level), which could strengthen respondents’ intention to refrainfrom visiting supermarkets or grocery stores (4) and going to their office (6) during thefollowing week. In contrast, we found no effect to increase their intention to avoid close
contact for the other nudge messages, among which the Simple Message rather weakened
their intention to refrain from going to gym (5).

Panel B in Figure 2 shows estimated parameters of receiving a nudge-based message,
with intention to take 15 types of infection prevention behavior as dependent variables.
We also here found significant and promotional effects for the Altruistic Message, which
15strengthened their intention to “3: try to avoid touching your face,” “5: avoid shaking
hands,” and “6: talk with others via phone or video call whenever possible.”

Additionally, the Loss-framed Altruistic Message were also found to have significant andpositive effects on some intention to engage in infection prevention behaviors. The
Selfish Message and the Simple Message had a positive effect on only one type of
behavior, while the Selfish and Altruistic Message showed an opposite effect.

Figure 2 Effects of Nudged-Based Messages on Intention

Notes: Significantly different from zero at the *10% level, **5% level, and ***1% level. A red line shows a promoting effect, while a blue line shows its
opposite effect.

16

In sum, we found that the Altruistic Message, which is followed by the Loss-framed
Altruistic Message, is effective for strengthening people’s intention to take contact
avoidance and infection prevention behaviors.

Behavior
Using the data of both the first experiment and its follow-up survey, we investigated how
respondents’ behaviors of contact avoidance and infection prevention changed before andafter seeing nudge-based messaged. We used for analysis a fixed-effect model estimation.

Panel A in Figure 3 shows estimated parameters of receiving a nudge-based message, byusing 10 types of contact behaviors by going out as dependent variables. As with the casewhere we used respondents’ intention as the outcomes, we found expected effects only
for the Altruistic Message (although still at a 10 percent level), which could reduce
people’s frequency of visiting cafes (3), taking planes (8), and participating in small
events (9). By contrast, no effect was observed for the other nudge-based messages topromote any contact avoidance behavior.

Panel B in Figure 3 shows estimated parameters of receiving a nudge-based message, byusing 15 types of infection prevention behaviors as dependent variables. Surprisingly,
any nudge-based message did not show an expected promotional effect, while they
showed more or less opposite effects. In particular, the Selfish Message had negative
effects on 7 types of the behaviors. Specifically, when receiving the message, thefrequency of cough etiquette (1), hand washing and disinfection of hands and fingers with17

alcohol (2), wearing a mask when talking (4), designating one person to do the shoppingor going out in a small group and during times when stores are not crowded (7), wearing
a mask when going out (11), getting plenty of rest and sleep (14), and eating nutritious
foods (15) are more likely to decrease compared to when receiving the message without
any nudge in the control group.

Figure 3 Effects of Nudge-Based Messages on Behavior

Notes: Significantly different from zero at the *10% level, **5% level, and ***1% level. A red line shows a promoting effect, while a blue line shows its
opposite effect.

18

Even the Altruistic Message, which promoted some contact avoidance behaviors, hadsome opposite effects, decreasing the frequency of avoiding crowds when shopping (7),getting plenty of rest and sleep (14), and eating nutritious foods (15). However, it ispossible that since people who received that message reduced the frequency of going out,
they may have moved together as a group for their few opportunities to go out. In
addition, since their frequency of shopping decreased, the quality of food and sleep may
have deteriorated.

In sum, our results indicate the possibility that the Altruistic Message promotes actual
some contact avoidance behaviors; however, the message has inevitable side effects atthe same time. The other four messages either have no effect on actual behavior or, if
they do, they have only negative effects, although some of the messages (in particular,
the Loss-framed Altruistic Message) show expected promotional effects on intention.

Life Satisfaction
We considered how respondents’ degree of life satisfaction changed during the 1-weekperiod after receiving the nudge-based messages, by using a fixed-effect model
estimation. We found from Figure 4 that the Altruistic Message, Loss-framed Altruistic
Message, Selfish Message, and Simple Message diminished some types of life
satisfaction. Specifically, in comparison to the control group, the intervention group
receiving the Altruistic Message showed a decrease in life satisfaction regarding leisuretime (3) and friendships (6). This is also a kind of side effect, which we introduced insubsection of Behavior. However, we found the decrease in life satisfaction relating to19

residential area, etc., for the Loss-framed Altruistic Message, Selfish Message, andSimple Message, which did not show any promotional effect on actual behavior.

Figure 4 Effects of Nudged-Based Messages on Life Satisfaction (“1: dissatisfied” to“5: satisfied”)

Notes: Significantly different from zero at the *10% level, **5% level, and ***1% level. A red line shows a promoting effect, while a blue line shows its
opposite effect.

All results in the three subsections were confirmed using the other estimation methods,
including an ordinal logit model.

Discussion and Conclusions
We found from analyses that the patterns of the effects of nudge-based messages on
respondents’ intention to engage in contact avoidance and infection prevention actions,actual behaviors, and life satisfaction can be classified into three categories. The firstcategory includes messages that can promote both their intention and actual behaviors,
but also reduce quality of sleep and diet and life satisfaction. The second category
includes messages that have a promotional effect on intention but no effect on actual
20

behavior and furthermore, reduce quality of life and satisfaction. The third category
includes messages that not only have no promotional effect on intention but actually
increase the frequency of contact behaviors and other risky behaviors as well as reduce
quality of life and satisfaction.

The first type is the Altruistic Message, which was found to strengthen intention to avoid
contact by going out and take measures to prevent infection as well as actually could
reduce people’s frequency of going to cafes, taking planes, and participating in small
events. In contrast, this type of message had side effects, including a deterioration inquality of sleep and diet, and life satisfaction. The second type is the Loss-framed
Altruistic Message and the third is the Selfish Message. No noteworthy and unifying
trends were observed in conjunction with the use of the Altruistic and Selfish message
and Simple message.

The intention reinforcing effects of the Altruistic message are consistent with thoseobserved in Jordan et al. (2020). However, while Jordan et al. (2020) reported observing
no difference between the effects of the Altruistic message and Altruistic and Selfish
message, our results for the Altruistic and Selfish Message show no effect on
respondents’ intentions. This might be explained by motivational crowding out, wherereferring to one’s own gain blocks a rise in altruistic motivation (Gneezy & Rustichini,2000). Additionally, this study’s respondents exposed to the Selfish message were likely
to engage in behaviors with a high risk of infection, while the Altruistic and Selfish

21

message did not have the effect of promoting such actions. Emphasizing the interests ofothers over one’s own interests might curb the appearance of the risky behaviors.

We found that only the Altruistic Message could have promotional effects on bothpeople’s intention and actual performance of contact avoidance and infection prevention
behaviors, while the intention-behavior gap was found for the Loss-framed Altruistic
Message. This is consistent with the results of previous studies, which demonstrated thata gain-framed message promotes disease prevention behaviors more than a loss-framedone (Detweiler et al., 1999; Toll et al., 2007).

Therefore, it is worth considering the employment of gain-framed altruistic messages topromote the actual behaviors as a countermeasure against the COVID-19 pandemic.
Some public and medical institutions have already employed the altruistic messages(British Broadcasting Corporation News, 2020; New Zealand Police, 2020), and our
findings will support the adequacy of such the efforts. However, the effects of ouraltruistic message on the behaviors could be weak, while their effects of reducing qualityof sleep and diet and life satisfaction has been robustly found. Considering these side
effects, policymakers should carefully consider whether the magnitude of thepromotional effects are sufficient.

Why did some nudge-based messages not have the effect of transforming actual
behaviors, even though they had the effect of strengthening intentions? One possibility isthat before our intervention, the respondents had already taken contact avoidance and22infection prevention actions at the maximum level they could and there may have been no
room for any further implementation. In addition, why does life satisfaction diminish
even though behavioral changes have not occurred in many respects? One possibility isthat receiving a nudge message may have made people acutely aware of theinconvenience to their current lifestyles as well as the need to prevent infection.

Future research should develop a nudge-based intervention that can promote both contact
avoidance and infection prevention behaviors sufficiently forcefully while suppressing
side effects of reducing quality of life and satisfaction. Also, this study only tracked
respondents’ behavior for approximately one week immediately after displaying thenudge-based messages, and thus the nudges’ effects were short-term. Their long-term
effects should also be investigated in future research.

Notes

1. Our OLS estimations controlled the effects of age, gender, schooling year, marriedstatus, annual household income, and information on response time, in addition toactual behavior during the previous one week before the intervention.

23

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Appendix

Appendix A. Appendix Figures and Tables

Figure A1 Screen of General Information about COVID-19

27

Figure A2 Screen of Control Group

Figure A3 Screen of “Altruistic Message” Group28

Figure A4 Screen of “Loss-framed Altruistic Message” Group

Figure A5 Screen of “Selfish Message” Group29

Figure A6 Screen of “Altruistic and Selfish Message” Group

Figure A7 Screen of “Simple Message” Group30

Table A1 Balance Test
ControlAltruistic

Loss-framed

SelfishAltruistic
Name of attributes
Age
FemaleSchooling year
Married status
Annual household income
No income information

Selfish andSimpleAltruistic

Mean (and standard deviation) of attributes
45.66245.42345.44545.07045.82645.507(13.801)(13.832)(13.857)(13.935)(13.942)(13.839)

0.508

0.495

0.495

0.504

0.509

0.496

(0.500)(0.500)(0.500)(0.500)(0.500)(0.500)14.561

14.576

14.61414.62714.62614.676(2.147)(2.105)(2.032)(2.073)(2.110)(2.086)

0.564

0.581

0.582

0.537

0.563

0.541

(0.496)(0.494)(0.494)(0.499)(0.496)(0.499)603.318618.485597.576616.628626.316614.127(350.553)(379.780)(358.093)(379.717)(344.483)(367.780)

0.201

0.178

0.187

0.188

0.193

0.188

(0.401)(0.383)(0.390)(0.391)(0.395)(0.391)

Number of observations
874
871
887
869
855
899
Notes: Some respondents did not answer annual household income. We imputed the average amount of the income for such
respondents while considering that they did not answer it by using the variable of no income information.

31