The Effects of Oxytocin on Fairness Perception and Related Prosocial Behaviors

The Modulatory Effects of Oxytocin on Fairness Perception and Related Prosocial Behaviors

This study aims to investigate the modulation of intranasally administered oxytocin (24 IU) on human fairness perception and related prosocial behaviors.

Study Overview

• Status: Recruiting
• Conditions: Healthy Adult Participants
• Intervention / Treatment: Drug: Oxytocin nasal spray; Drug: Placebo

Detailed Description

Fairness preference is a cornerstone of human sociality, often driving individuals to incur personal costs in order to uphold fairness norms. Oxytocin (OT), a neuropeptide, is considered a potential modulator of prosocial behavior, yet its specific mechanism of action in fairness decision-making remains unclear. Previous research has predominantly focused on the overall effects of OT on behaviors, without differentiating its roles across distinct processing stages such as cognitive evaluation and emotional anticipation. Furthermore, there is a lack of systematic investigation into whether its effects are modulated by social context and gain-loss contexts. Using a randomized, double-blind, placebo-controlled between-subjects design, the present study combines functional magnetic resonance imaging (fMRI) with the Dictator Game (DG) and the Ultimatum Game (UG) to elucidate how intranasal OT influences fairness perception and related prosocial behavior. The UG additionally involves strategic considerations of the proposer arising from the recipient's ability to reject the offer. Participants, act as proposers, are instructed to rate their perceived levels of fairness and guilt when receiving advantageous inequity and fair allocations in both gain and loss contexts. Following ratings, participants make decisions of accepting or rejecting the current allocation. Their brain activity and behavioral responses will be synchronously recorded during the tasks, and scores of questionnaires including Positive and Negative Affect Schedule, State-Trait Anxiety Inventory, Sensitivity to Punishment and Sensitivity to Reward Questionnaire, Social Value Orientation, Self-Report Altruism Scale, Prosocial Tendencies Measure, Behavioral Inhibition System and Behavioral Activation System Scale, Interpersonal Reactivity Index, Toronto Alexithymia Scale, Beck Depression Inventory-Ⅱ, Guilt and Shame Proneness Scale, Test of Self-Conscious Affect are also collected before the experiment.

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Shuxia Yao, Dr; Phone Number: 86+18111297596; Email: yaoshuxia@uestc.edu.cn

Study Locations

• China
  • Sichuan
    • Chengdu, Sichuan, China, 611731
      • Recruiting
      • University of Electronic Science and Technology of China (UESTC)
      • Contact: Shuxia Yao, Dr; Phone Number: 86+18111297596; Email: yaoshuxia@uestc.edu.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy subjects without past or current psychiatric or neurological disorders.

Exclusion Criteria:

• History of head injury; pregnant, menstruating, taking oral contraceptives; medical or psychiatric illness.
• The presence of metal in the body or claustrophobia.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: oxytocin group; male and female subjects with oxytocin treatment	Drug: Oxytocin nasal spray; intranasal administration of oxytocin (24IU)
Placebo Comparator: placebo group; male and female subjects with placebo treatment	Drug: Placebo; intranasal administration of placebo (24IU)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fairness rating scores	Participants are asked to rate their perceived levels of fairness on a 9-point Likert scale (1 = highly fair, 9 = highly unfair) to the computer's allocation in each trial.	1 hour
Anticipated guilt rating scores	Participants are asked to rate the anticipated guilt they would feel if they accepted the allocation given by the computer in each trial. Ratings were conducted on a 9-point Likert scale (1 = not at all, 9 = highly guilty).	1 hour
The binary decision to the initial allocation	Participants are asked to makde decisions of accepting or rejecting the allocation provided by the computer in each trial.	1 hour
Brain activity patterns	Brain activity patterns in response to the outcome of the allocation given by computer and the binary decision. We will examine these brain response patterns via both the conventional univariate analysis and the machine learning-based multivariate pattern analysis (MVPA) approaches.	1 hour

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Inequity aversion parameters derived from the Fehr-Schmidt model	Inequity aversion parameters derived from the Fehr-Schmidt model are used to elucidate whether OT would modulate inequity aversion. This model-based analysis was conducted based on choices using hierarchical Bayesian modeling. In the Fehr-Schmidt model, the subjective value of a given allocationis determined by one's own and the other's allocation using the following formula: SV(Mself, Mother) = Mself - βmax{ Mself - Mother, 0}, Mself ≠ Mother where Mself is one's payoff and Mother is the other's payoff. Parameter β represents the weight assigned to inequity. Higher parameter values indicate a stronger degree of inequity aversion in participants.	1 hour

Collaborators and Investigators

• Sponsor: University of Electronic Science and Technology of China
• Investigators: Principal Investigator: Shuxia Yao, Dr, University of Electronic Science and Technology of China

Study record dates

Study Major Dates

• Study Start (Actual): September 5, 2026
• Primary Completion (Estimated): December 30, 2026
• Study Completion (Estimated): December 31, 2026

Study Registration Dates

• First Submitted: September 3, 2026
• First Submitted That Met QC Criteria: September 8, 2026
• First Posted (Actual): September 11, 2026

Study Record Updates

• Last Update Posted (Actual): September 11, 2026
• Last Update Submitted That Met QC Criteria: September 8, 2026
• Last Verified: September 1, 2026

More Information

Terms related to this study

• Keywords: oxytocin; fMRI; prosocial behavior; fairness perception
• Additional Relevant MeSH Terms: Behavior; Social Behavior; Altruism
• Other Study ID Numbers: UESTC-neuSCAN-105

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No