Trait Injustice, Social Exclusion, and Anger

Study Overview
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Brief Summary
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Participants will be randomly allocated to one of two experimental conditions: social exclusion or social inclusion. Participants, but not experimenters will be blind to the assignment. Pre- and post-tests will be administered. Participants will be offered 7 euros in compensation for participating.

Official Title
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Trait Injustice and Its Effects on Anger Induced by Social Exclusion

Conditions
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General Population

Intervention / Treatment
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* Other: Cyberball experimental task


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Being over 18 years of age Signs the informed consent Can read and understand Spanish Exclusion Criteria: Being younger than 18 years of age Does not sign the informed consent Cannot read or understand Spanish

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: The two conditions, based on the experimental task called Cyberball, will be: social inclusion and social exclusion.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Social exclusion<br>Cyberball is a ball-passing task in which the participant plays with two virtual players. In this condition, the user receives fewer passes than the other two participants (i.e., 10 out of 60). | Other: Cyberball experimental task<br>* Cyberball is an experimental task in which participants have to pass a ball to two virtual players during 60 passes in total<br>|
| Active Comparator: Social inclusion<br>Cyberball is a ball-passing task in which the participant plays with two virtual players. In this condition, the user receives a comparable number of passes than the other two participants (i.e., 20 out of 60). | Other: Cyberball experimental task<br>* Cyberball is an experimental task in which participants have to pass a ball to two virtual players during 60 passes in total<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Anger State from baseline to end of the experiment | The STAXI-2 includes a measure of anger state (15 items) with responses ranging from 1=Absolutely not to 3=A lot | The STAXI-2 will be administered twice: at Baseline and at the same day of Baseline assessment just after the experimental task (end of study) | 
| Trait Injustice | The Trait Injustice Experiences Questionnaire is a measure of perceived trait injustice beliefs that has 12 items, with responses ranging from 0=never to 4=always. This measure will be used as moderator of the effects of the experiment on anger | This measure will be administered at Baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Frustration Discomfort Scale | This is a measure of frustration intolerance. The scale has 28 items that are gouped in 4 subscales. Items have a 1-to-5 response scale ranging from nothing to a lot. In addition to trait injustice, this measure will also be used in secondary analyses as a moderator of the effects of the experiment on anger | This measure will be administered at Baseline | 
| Change in State Injustice from baseline to end of the experiment | The State Injustice Experiences Questionnaire is a measure of perceived state injustice beliefs that has 12 items, with responses ranging from 0=never to 4=always. This measure will be used as an experimental check (whether exclusion in the experiment effectively increased the sense of injustice in the short term) | This measure will be administered twice: at Baseline and at the same day of Baseline assessment just after the experimental task (end of study) | 
| Change in State Anxiety from baseline to end of the experiment | The STAI-S is a measure of perceived state anxiety that has 20 items, with responses ranging from 0=not at all to 3=a lot. This measure will be used as an experimental check (whether exclusion in the experiment effectively increased anxiety in the short term) | This measure will be administered twice: at Baseline and at the same day of Baseline assessment just after the experimental task (end of study) | 
| Cyberball Experiences post-experimental check Questionnaire | In addition to exploring the effects of the experimental task on anxiety and anger, the Cyberball includes a measure of impact of the task on perceived inclusion and related concepts (isolation, belonging, perceived number of passes received, etc.). This will also be used as an experimental check | This measure will be administered at the same day of Baseline assessment just after the experimental task (end of study) |