Behavioral Game Intervention for Reducing Bullying and Discrimination in La Paz, Bolivia

Last registered on April 24, 2026

Pre-Trial

Trial Information

General Information

Title
Behavioral Game Intervention for Reducing Bullying and Discrimination in La Paz, Bolivia
RCT ID
AEARCTR-0017837
Initial registration date
April 20, 2026

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
April 24, 2026, 8:58 AM EDT

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

Locations

Primary Investigator

Affiliation
Universidad Privada Boliviana

Other Primary Investigator(s)

PI Affiliation
Universidad Privada Boliviana

Additional Trial Information

Status
In development
Start date
2026-02-18
End date
2026-08-31
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
School violence, discrimination, and gender-based bullying remain persistent challenges in Bolivia despite progressive legal frameworks intended to protect children and adolescents. Recent research conceptualizes bullying not as a dyadic conflict but as a collective social process in which bystanders play a decisive role in either sustaining or interrupting aggression. This study evaluates a behavioral intervention designed to activate prosocial bystander behavior by reshaping the social meaning and incentives associated with aggression and defense.

The intervention employs game-based mechanisms to simulate peer interactions in a controlled environment, using visual, emotional, and strategic nudges to alter how social status is earned within the group. Rather than directly discouraging aggression, the games make defensive and empathetic actions visible, rewarded, and socially salient, thereby shifting perceived norms around acceptable behavior. Two thematic treatment arms are implemented. One card-based game addressing racism and classism, assigns players rotating roles of aggressor, target, and bystander, allowing them to accumulate points through either empathetic defense or reinforcement of bullying. Another focused on gender-based violence, is a social deduction game with hidden roles in which defending vulnerable players entails personal costs but confers social recognition.

The study hypothesizes that norm change operates through multiple mechanisms: social learning, as students observe peers engaging in defense; norm reinforcement, as prosocial behavior becomes collectively validated; and belief updating, as defending is reframed as effective and socially valued. To mitigate social desirability bias, the study combines self-reported survey measures with incentivized behavioral outcomes derived from in-game decisions that reflect real-time trade-offs under peer observation. These behavioral measures capture latent preferences and responses that are not directly observable through attitudinal surveys alone. Together, this design allows for a rigorous assessment of both the direct impact of the intervention and its capacity to generate broader social contagion within schools.
External Link(s)

Registration Citation

Citation
Heller, Lorena and Joaquin Morales. 2026. "Behavioral Game Intervention for Reducing Bullying and Discrimination in La Paz, Bolivia." AEA RCT Registry. April 24. https://doi.org/10.1257/rct.17837-1.0
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Experimental Details

Interventions

Intervention(s)
This study evaluates a school-based behavioral intervention aimed at reducing bullying, racism, classism, and gender-based violence among secondary school students in La Paz, Bolivia. The intervention leverages game-based experiential learning combined with behavioral nudges to shift peer norms and promote prosocial bystander behavior.
The intervention consists of two treatment arms and one control condition:
* Control group: Students play a non-interactive, chance-based game designed to preserve engagement while minimizing social interaction and behavioral influence.
* Treatment 1 (Racism and Classism): Students participate in a card-based game simulating bullying dynamics. Players assume roles and make real-time decisions to attack, defend, or reinforce aggression. The game incorporates empathy and prosocial action cards, and rewards defending behavior through point accumulation.
* Treatment 2 (Gender-Based Violence): Students engage in a role-playing game with hidden identities (bullies, victims, bystanders). The game introduces strategic and moral trade-offs, where bystanders decide whether to intervene at a personal cost under conditions of uncertainty and social pressure.
Across both treatments, the key innovation lies in the use of visual and emotional nudges embedded in game materials. These nudges aim to increase empathy and perspective-taking; make prosocial behavior visible and socially rewarded; shift the perceived social payoff from aggression to cooperation.
The intervention targets bystander behavior as the primary mechanism of change, based on the premise that peer responses determine whether bullying escalates or stops. By altering the social incentives and normative expectations within peer groups, the intervention seeks to move classrooms from antisocial to prosocial equilibria.
Intervention (Hidden)
This study implements a school-based behavioral intervention designed to reduce bullying, racism, classism, and gender-based violence (GBV) among secondary school students in La Paz, Bolivia. The intervention is grounded in a behavioral economics framework that conceptualizes bullying as a peer-driven coordination problem, where bystander responses and social incentives determine whether aggressive behaviors persist or dissipate.

The core intervention consists of structured behavioral games that simulate real-world social interactions within a controlled environment. These games are designed to elicit revealed preferences over prosocial versus antisocial actions under conditions of peer observation, social pressure, and repeated interaction. The intervention does not rely on direct instruction or punitive framing; instead, it modifies the choice architecture through embedded visual and emotional nudges that influence how participants perceive and evaluate their decisions.

The study includes three experimental conditions:

Control condition:
Students participate in a neutral, chance-based game (Chutes and Ladders) that preserves engagement and emotional variability but minimizes strategic interaction and social decision-making. This condition serves to isolate the behavioral impact of social interaction and nudging present in the treatment arms.

Treatment 1 – Racism and Classism (Capiescuela):
Students play a card-based behavioral game that replicates bullying dynamics. In each round, participants can assume roles as aggressors, victims, or bystanders. Players choose among actions such as initiating aggression, defending others, or reinforcing bullying. The game incorporates four types of cards: bullying actions, bystander responses, defensive actions, and empathy-based prompts. Players accumulate points associated with either prosocial (empathy) or antisocial (reinforcement of bullying) behaviors. The game is repeated over multiple rounds, allowing for learning and adaptation. The structure captures key elements of real-world interactions, including social costs of intervention, reputational incentives, and peer influence.

Treatment 2 – Gender-Based Violence (La Noche del Cóndor):
Students participate in a role-playing, hidden-identity game that models bullying and GBV dynamics under incomplete information. Participants are randomly assigned roles (aggressors, victims, bystanders) with asymmetric information. In each round, aggressors select a victim, and bystanders decide whether to intervene at a personal cost. Intervention decisions have immediate and observable consequences, including changes in group composition and voting power. The game introduces strategic uncertainty, moral trade-offs, and collective accountability mechanisms, requiring participants to form beliefs about others’ behavior and update them over time.

Across both treatment arms, the intervention integrates behavioral nudges through visual elements, narratives, and card content. These nudges are designed to:

Increase the salience of victims’ experiences (affective framing)
Enhance the perceived moral and social rewards of defending behavior
Reduce ambiguity about appropriate responses to bullying
Shift expectations about peers’ willingness to intervene

Importantly, the nudges do not alter the formal rules or payoffs of the games but instead target beliefs, emotions, and normative expectations, consistent with nudge theory.

The intervention is implemented in small groups (typically 4–10 students), with multiple rounds of interaction to allow for behavioral reinforcement and social learning. The repeated nature of the games enables the emergence of equilibrium dynamics, where groups may converge toward either prosocial (high intervention) or antisocial (high reinforcement of bullying) patterns depending on early actions and expectations.

To capture both direct and indirect effects, the study employs a two-stage randomized design. Schools are first randomly assigned to treatment or control conditions. Within treated schools, classrooms are further randomized into direct exposure (participation in the behavioral games) or indirect exposure (no direct participation but shared school environment with treated peers). This design allows for the identification of spillover effects, including social imitation, norm diffusion, and peer influence across classrooms.

The intervention is complemented by a structured debriefing and educational session following gameplay. This session reinforces key concepts such as empathy, respect, and institutional resources, and provides a safe space for reflection. However, because all experimental arms receive a similar thematic framing, differences in outcomes can be attributed to the behavioral mechanisms embedded in the games rather than to information provision alone.

Data collection combines behavioral measures derived from in-game decisions with survey-based instruments administered at baseline and one-month follow-up. Behavioral measures include choices related to defending, reinforcing, or ignoring bullying, as well as cooperation and fairness in incentivized allocation tasks. Survey measures capture attitudes, norms, and self-reported behaviors related to discrimination and violence.

Overall, the intervention tests whether low-cost, scalable behavioral tools that reshape social incentives and peer expectations can shift group dynamics toward prosocial equilibria, reducing the prevalence and acceptance of bullying, racism, classism, and gender-based violence in school environments.
Intervention Start Date
2026-03-23
Intervention End Date
2026-06-30

Primary Outcomes

Primary Outcomes (end points)
Prosociality Index
Tolerance to Injustice
Social Distance (Racism and Classism): Measured using an adapted Bogardus Social Distance Scale (BSDS). The outcome is the average social distance score toward different profiles (range: 1–5), where lower values indicate higher prejudice and higher values indicate greater acceptance.
Gender Norms and GBV Attitudes: Measured using an adapted Gender Role Attitudes Scale (GRAS). Outcomes include composite indices and sub-dimensions capturing:

Acceptance of gender equality (egalitarian attitudes)
Endorsement of sexist beliefs and norms that justify gender-based violence
Primary Outcomes (explanation)
Both the Prosociality Index and Tolerance to Injustice (Justice Enforcement) are derived from incentivized allocation decisions in a modified Third-Party Punishment (Dictator) Game. This design allows us to observe costly prosocial behavior in a controlled setting, minimizing social desirability bias.

Game Structure:

Each participant is assigned the role of a third-party decision-maker (observer) in a three-player setting:

An Actor is endowed with 10 tokens and instructed to make an allocation decision toward a passive Recipient. The allocation is pre-determined to be highly unequal (i.e., the Actor keeps most tokens), thereby creating an unfair outcome.
The Participant (third party) observes this allocation and is then endowed with 5 tokens.
The participant is asked to choose how to use their tokens under two possible actions:
Keep tokens: The participant retains their full endowment, accepting the unfair outcome.
Punish the Actor: The participant can spend tokens to reduce the Actor’s payoff. Each token spent by the participant reduces the Actor’s payoff by a fixed multiple (e.g., 1 token spent reduces 3 tokens from the Actor).
This decision is made privately and has real payoff consequences within the experimental setting.
Tolerance to Injustice (Justice Enforcement):
Defined as the number of tokens the participant chooses to spend on punishing the unfair Actor (range: 0–5).
Higher values indicate lower tolerance to unfairness and a greater willingness to engage in costly punishment (active bystander behavior).
A value of zero indicates full tolerance of the unfair allocation.
Prosociality Index:
Constructed from the same decision as the willingness to sacrifice personal resources to improve fairness outcomes. Specifically, it reflects the extent to which participants incur a personal cost to reduce inequality.

Higher values indicate stronger prosocial preferences and fairness concerns.
Lower values (or zero) indicate self-regarding preferences and acceptance of inequity.

Secondary Outcomes

Secondary Outcomes (end points)
In addition to experimental outcomes, the study includes a self-reported measure of overall exposure to bullying dynamics, collected through student surveys at baseline and endline. The measure reflects the student’s overall involvement in or exposure to bullying-related behaviors within the school environment.
Persistence Outcomes

All primary behavioral and attitudinal outcomes are measured both immediately after the intervention and at a one-month follow-up, allowing assessment of the persistence of treatment effects.
Secondary Outcomes (explanation)
Students report the frequency of a range of bullying-related behaviors over a defined recall period. These behaviors include:

Physical aggression (e.g., hitting, pushing)
Verbal harassment (e.g., insults, teasing)
Social exclusion (e.g., ignoring, spreading rumors)
Discriminatory behaviors (e.g., based on ethnicity, socioeconomic status, or gender)
Gender-based harassment (e.g., sexual comments, controlling behaviors)

Responses are recorded using ordered categorical frequency scales (e.g., “never,” “once,” “a few times,” “many times”).

Experimental Design

Experimental Design
The study employs a cluster-randomized controlled trial with two-stage randomization. In the first stage, secondary schools in La Paz are randomly assigned to either treatment or control conditions. In the second stage, within treated schools, classrooms are randomly assigned to either receive the intervention (direct exposure) or not (indirect exposure), enabling the identification of spillover effects.

The intervention consists of game-based behavioral activities designed to influence social interactions and decision-making among students. Two treatment arms are implemented, each using structured games that simulate peer dynamics related to cooperation, conflict, and social behavior. The control group participates in a neutral, non-interactive activity designed to maintain engagement without inducing social interaction effects.

Outcomes are measured using a combination of behavioral tasks and student surveys, administered immediately after the intervention and at a one-month follow-up.
Experimental Design Details
The study is implemented as a cluster-randomized controlled trial with two-stage randomization in secondary schools in La Paz, Bolivia. The unit of randomization at the first stage is the school, and at the second stage the classroom within treated schools.

In the first stage, participating schools are randomly assigned to either treatment or control. In the second stage, within schools assigned to treatment, classrooms are randomly allocated to either:
* Direct treatment (D): students participate in the behavioral intervention
* Spillover group (S): students do not participate directly but are exposed to treated peers within the same school
* Classrooms in control schools constitute the pure control group (C).

This design allows identification of:
* The average treatment effect (ATE) by comparing treated schools to control schools
* Spillover effects by comparing untreated classrooms in treated schools to classrooms in control schools

The intervention consists of behavioral, game-based activities designed to simulate peer interactions related to bullying, discrimination, and bystander decision-making. The games are implemented in small groups within classrooms and involve repeated rounds of interaction.

There are two treatment arms:

* Treatment 1: Racism and Classism (Capiescuela)
A card-based interactive game in which students take on roles that emerge endogenously during gameplay (e.g., aggressor, victim, bystander). Players make decisions such as initiating aggression, defending others, or reinforcing bullying. The game includes different types of cards (bullying, bystander reactions, defense, and empathy-based actions). Outcomes are determined through a point system that rewards either prosocial (defending) or antisocial (reinforcing) behaviors. The repeated structure allows for learning, adaptation, and peer influence.

* Treatment 2: Gender-Based Violence (La Noche del Cóndor)
A role-playing, hidden-identity game with three roles (aggressors, victims, bystanders). Aggressors select victims, while bystanders decide whether to intervene under conditions of uncertainty and potential social cost. Intervention decisions affect survival, group composition, and collective outcomes. The game incorporates discussion, voting, and repeated rounds, capturing strategic behavior, belief formation, and coordination dynamics.
Both treatment arms incorporate visual and emotional nudges embedded in cards, narratives, and game elements. These nudges are designed to:

* Increase empathy and perspective-taking
* Raise the salience of harm experienced by victims
* Increase the perceived moral and social returns to defending behavior
* Reduce ambiguity about appropriate responses to bullying
* Shift beliefs about peers’ willingness to intervene

The intervention targets bystander behavior as the central mechanism, aiming to shift group dynamics from equilibria that sustain bullying toward equilibria characterized by prosocial intervention and norm enforcement.
Students in the control group participate in a non-strategic, chance-based game (Chutes and Ladders). This activity maintains engagement and emotional variability but removes social interaction, strategic decision-making, and exposure to behavioral nudges. This ensures that any observed treatment effects are driven by the social and behavioral components of the intervention rather than by participation in a game per se.

Data are collected at the individual (student) level using a combination of:
* Behavioral measures: decisions made during gameplay and incentivized experimental tasks (e.g., third-party punishment game) capturing prosociality, tolerance to injustice, and responses to unfairness.
* Survey measures: self-reported attitudes and behaviors related to bullying, discrimination (racism, classism), and gender-based violence. A global bullying index captures overall exposure to bullying dynamics.

Data collection occurs at two points:
* Post-intervention (baseline for outcomes)
* One-month follow-up (endline)
This allows estimation of both immediate treatment effects and short-term persistence.
Randomization Method
Randomization was conducted in-office using a computer-based random number generator. Schools were first randomly assigned to treatment or control conditions. Within treated schools, classrooms were then randomly assigned to either direct treatment or spillover groups. Randomization was implemented prior to fieldwork using reproducible code to ensure transparency and replicability.
Randomization Unit
Randomization was conducted at two levels:

First stage: The unit of randomization is the school, which is assigned to either treatment or control.
Second stage: Within treated schools, the unit of randomization is the classroom, which is assigned to either direct treatment (participation in the intervention) or spillover (no direct participation).

The primary unit of analysis is the individual student, with clustering at the school level for inference.
Was the treatment clustered?
Yes

Experiment Characteristics

Sample size: planned number of clusters
40 Schools, 4 courses per school and in average 25 students per classroom.
Sample size: planned number of observations
The planned number of observations is 4,000 observations (students).
Sample size (or number of clusters) by treatment arms
40 schools × 4 classrooms per school × 25 students per classroom = 4,000 students

So, the planned sample size is 4,000 observations (students).
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
The study is powered to detect a minimum effect size of 0.30 standard deviations in the main outcomes. Unit: Individual student-level outcomes Effect size: 0.30 standard deviations Percentage interpretation: Equivalent to detecting a change of approximately 30% of a standard deviation This calculation assumes: Power: 80% Significance level (α): 5% Design: Cluster-randomized with two levels (school and classroom) Intra-cluster correlation (ICC): 0.05 at the school level and 0.10 at the classroom level Average cluster size: 30 students per classroom Simulation results indicate that with the planned sample (e.g., ~40 schools with multiple classrooms per school), the design achieves approximately 80–90% power to detect this effect size.
Supporting Documents and Materials

Documents

Document Name
Protocol in Spanish
Document Type
irb_protocol
Document Description
File
Protocol in Spanish

MD5: e45405147ec6f1967dfba45c567d5011

SHA1: 1d056630896b64edaac350f0d19176c64ca0c07f

Uploaded At: April 20, 2026

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IRB

Institutional Review Boards (IRBs)

IRB Name
Comite de Etica- Universidad Privada Boliviana
IRB Approval Date
2026-02-04
IRB Approval Number
CET-004022026
Analysis Plan

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Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
No
Data Collection Complete
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

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Reports & Other Materials