Prosocial incentive versus financial incentive in biodiversity conservation: A field experiment

Last registered on February 13, 2025
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Pre-Trial

Trial Information

General Information

Title
Prosocial incentive versus financial incentive in biodiversity conservation: A field experiment
RCT ID
AEARCTR-0010210
Initial registration date
October 12, 2022

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
October 17, 2022, 5:29 PM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Last updated
February 13, 2025, 8:04 PM EST

Last updated is the most recent time when changes to the trial's registration were published.

Locations

Country
Japan
Region

Primary Investigator

Name
Shusaku Sasaki
Affiliation
The University of Osaka
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Other Primary Investigator(s)

PI Name
Takahiro Kubo
PI Affiliation
National Institute for Environmental Studies
Contact Investigator

Additional Trial Information

Status
Completed
Start date
2022-09-15
End date
2025-01-31
Keywords
Agriculture, Behavior, Environment & Energy, Other
Additional Keywords
Conservation actions, Species information, Invasive species, Rare species, Charitable giving, Financial reward, Incentive, Information provision, Public good, Smartphone app, Posting, Behavioral economics, Experimental economics, Japan
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Citizens exhibit interests for a variety of social contribution activities, including biodiversity conservation ones. However, it is difficult for one citizen to participate in multiple activities with the same effort. There are both activities in which they want to directly participate and activities in which they would be satisfied to be indirectly involved.

In this study, we introduce a scheme whereby when people contribute to the activity in which they want to directly participate, another positive action also occurs in the social contribution activity in which they want to be indirectly involved. We experimentally test how much the scheme facilitates the former behavior.

Specifically, we introduce a matching scheme whereby people post species information on a smartphone app related to biodiversity conservation, and monetary donations are made to related activities (e.g., saving endangered species, etc.). We conduct a field experiment with the app users, measure the scheme’s effect on their posting behavior during implementation, and evaluate the lasting impact after the scheme is deactivated. To examine the significance of exposures to species under the pandemic, we also measure spillover effects on physical activities and mental health.

Furthermore, we measure the behavior change effect of another scheme that gives financial rewards for posting species information and investigate which charitable matching or reward matching has a greater behavior change effect. We also examine how the relative relationship depends on the app users’ attributes and perceptions.
External Link(s)

Registration Citation

Citation
Sasaki, Shusaku and Takahiro Kubo. 2025. "Prosocial incentive versus financial incentive in biodiversity conservation: A field experiment." AEA RCT Registry. February 13. https://doi.org/10.1257/rct.10210-3.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
We randomly assign 900 participants to either of the control group, prosocial treatment group, or financial treatment group (300 participants x 3 groups). We set a two-week treatment period, during which those assigned to the prosocial treatment group, or financial treatment group receive the following interventions, respectively:

Prosocial treatment: Based on the number of species information posted by each user, the experimenter donates to activities related to biodiversity conservation.
Financial treatment: Based on the number of species information posted by each user, the experimenter gives them financial rewards that can be used for their online shopping.
Intervention (Hidden)
Intervention Start Date
2022-10-17
Intervention End Date
2022-10-28

Primary Outcomes

Primary Outcomes (end points)
1) Number of species information posted on weekdays
2) Number of species information posted on weekends or holidays
Primary Outcomes (explanation)
The primary outcomes are automatically recorded by the app.

Secondary Outcomes

Secondary Outcomes (end points)
1) Number of species photos posted on weekdays
2) Number of species photos posted on weekends or holidays
3) Physical activities (Weekday steps and weekend steps)
4) Mental health (k6)
Secondary Outcomes (explanation)
Among the secondary outcomes, the variables 1) and 2) are are automatically recorded by the app. Here, the primary outcomes (number of posted species information) are not equal to the two secondary outcomes (number of posted species photos), which count even if a user posts multiple photo of the same organism.

The variables 3) and 4) are collected in a self-report format in surveys.

Experimental Design

Experimental Design
In this study, we collaborate with a company that provides a smartphone app for citizens to collect, post, and record species information, and conduct a field experiment with its users.

We randomly assign 900 participants to either of the control group, prosocial treatment group, or financial treatment group (300 participants x 3 groups). We set a two-week treatment period, during which those assigned to the prosocial treatment group, or financial treatment group receive the following interventions, respectively:

Prosocial treatment: Based on the number of species information posted by each user, the experimenter donates to activities related to biodiversity conservation.
Financial treatment: Based on the number of species information posted by each user, the experimenter gives them financial rewards that can be used for their online shopping.
Experimental Design Details
In this study, we collaborate with a Japanese company that provides a smartphone app for citizens to collect, post, and record species information, and conduct a field experiment with its users. The app was launched in May 2017, and the number of users exceeded 400,000 in April 2022.

When users take photos of plants and animals they see outdoors and post them to the app, the app determines their names and types based on the AI. At the same time, the app records its species information as well as the time and place of taking and posting the photos. Citizens collecting species information and sharing it to the public will lead to a better understanding for what kind of, where, and how many species, including rare and invasive ones, are living. Ascertaining this actual situation is essential for biodiversity conservation.

We collect participants for this field experiment in the following ways: We post a recruitment ad on the front page of the app. On the transition page, we obtain opt-in participation consent from users. The target number of participants is around 900, based on our research budget, etc.

After obtaining their participation consent, we then ask them to complete the first survey. The survey includes a set of questions to ascertain their socioeconomic demographics, as well as their use of the app, daily steps, mental health, reasons for participating in this event, etc.

Next, we randomly assign them to either of the control group, prosocial treatment group, or financial treatment group (300 participants x 3 groups). We set a two-week treatment period, during which those assigned to the prosocial treatment group, or financial treatment group receive the following interventions, respectively:

Prosocial treatment: Based on the number of species information posted by each user, the experimenter donates to activities related to biodiversity conservation.
Financial treatment: Based on the number of species information posted by each user, the experimenter gives them financial rewards that can be used for their online shopping.

After the treatment period, we conduct the second survey to again ascertain their daily steps, mental health, etc.

Using randomization and difference-in-differences approach, we measure the impact of each treatment on changes in the number of posted species information and that of posted species photos. We also measure the impact of each intervention on changes in daily steps and mental health.

Among the outcome variables, the number of posted species information and that of posted species photos are automatically recorded by the app. The analysis uses for the variables the difference between the baseline period prior to participation and the treatment period. Daily steps and mental health are collected in a self-report format in two surveys, as described above. The analysis uses for the variables the difference between the two surveys.
Randomization Method
Stratified randomization. The strata are based on 1) number of species information posted by users during the baseline period, and 2) their prosocial or selfish motivations for participation.
Randomization Unit
Individuals
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
N/A
Sample size: planned number of observations
900 app users
Sample size (or number of clusters) by treatment arms
300 users in the control group, 300 users in the prosocial treatment group, and 300 users in the financial treatment group
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
Center for Infectious Disease Education and Research, Osaka University IRB
IRB Approval Date
2022-09-01
IRB Approval Number
2022CRER0901
Analysis Plan

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Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
Yes
Intervention Completion Date
October 28, 2022, 12:00 +00:00
Data Collection Complete
Yes
Data Collection Completion Date
March 31, 2023, 12:00 +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
N/A
Was attrition correlated with treatment status?
No
Final Sample Size: Total Number of Observations
830 individuals
Final Sample Size (or Number of Clusters) by Treatment Arms
Control group (n = 275) Prosocial incentive treatment group (n = 273) Financial incentive treatment group (n = 282)
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Yes
Program Files URL
https://doi.org/10.1016/j.ecolecon.2024.108506
Reports, Papers & Other Materials

Relevant Paper(s)

Abstract
Ascertaining the number, type, and location of plant, insect, and animal species is essential for biodiversity conservation. However, it is difficult to comprehensively monitor the situation using only expert-led surveys, and therefore information voluntarily provided by citizens is helpful in determining species distribution. To effectively encourage citizens to share data, this study proposed a prosocial incentive that rewards providing species information with donations for endangered species conservation activities. We conducted a field experiment with users (N = 830) of a widely used Japanese smartphone app “biome” where they post species photos and measured the incentive's effect on their posting behavior. In addition, we measured the effect of a financial incentive that provides monetary rewards for posting species photos and compared the two incentives' effects. The analyses revealed that while the prosocial incentive did not increase the number of posts on average, it could influence the content of the posts, increasing the proportion of posts on rare species. In contrast, the financial incentive significantly increased the total number of posts and, in particular, the number of posts on less rare and invasive species. Our results indicate that the prosocial and financial incentives could stimulate different motivations and encourage different posting behaviors.
Citation
Sasaki, S., Kubo, T., & Kitano, S. (2025). Prosocial and financial incentives for biodiversity conservation: A field experiment using a smartphone app. Ecological Economics, 230, 108506.
URL
https://doi.org/10.1016/j.ecolecon.2024.108506

Reports & Other Materials