Alcohol and the Social Brain: An Alcohol-Administration Hyperscanning Study Employing a Within-Subject Design

The study investigates the effects of alcohol consumption on social and individual behaviors using a within-subject design. Participants, aged 21-30, will attend two laboratory sessions approximately one week apart, participating as part of a dyad (pair). During one session, they will consume an alcoholic beverage, while in the other, they will receive a control beverage, with the order of conditions randomized. This design facilitates direct within-participant comparisons of behaviors and neural activity in intoxicated versus sober states.

To achieve these aims, the study employs EEG technology to explore intra-brain and inter-brain dynamics during social interactions. Additionally, validated self-report questionnaires will capture data on mood, social bonding, and other psychological variables. The findings are expected to enhance understanding of alcohol's role in social reward processes and contribute to developing evidence-based prevention and intervention strategies for alcohol use disorder.

Study Overview

• Status: Recruiting
• Conditions: Alcohol Drinking; Alcoholism; Alcohol; Harmful Use; Binge Drinking; Alcohol Intoxication; Alcohol Use Disorder (AUD)
• Intervention / Treatment: Drug: Alcohol beverage; Other: Control - non alcoholic beverage

Detailed Description

Objective:

Alcohol's ability to enhance social bonding and modulate mood in social contexts has been identified as a key factor contributing to its reinforcing properties and risk for Alcohol Use Disorder (AUD). While prior research has demonstrated alcohol's role in enhancing social interactions, laboratory studies often fail to replicate the real-world context in which most alcohol consumption occurs-social settings with familiar companions. This discrepancy limits our understanding of the mechanisms through which alcohol exerts its effects in social contexts.

This study is the first to employ EEG hyperscanning methods to investigate the inter- and intra-brain mechanisms underlying alcohol's social rewards within dyadic interactions. Specifically, the study aims to characterize how alcohol modulates social bonding, emotional regulation, and neural synchrony during social interactions, and to identify the cognitive and affective processes driving alcohol's reinforcing properties. The findings are expected to deepen understanding of the role of alcohol in social dynamics and inform interventions for AUD.

Study Population:

The study will recruit 200 participants, aged 21-30, who self-identify as regular social drinkers and with no reported history of severe alcohol use disorder.

Design:

This within-subject laboratory study involves two experimental sessions spaced approximately one week apart. Each session includes participants interacting in dyads with a stranger, where they will consume either a moderate dose of alcohol (target BAC ~0.08%) or a non-alcoholic control beverage, with the order randomized between sessions. Participants will engage in structured and unstructured tasks during each session, allowing for the evaluation of behavioral, emotional, and neural outcomes in both intoxicated and sober states.

• EEG Hyperscanning: Neural activity will be recorded simultaneously from both members of the dyad using EEG hyperscanning technology. This allows for the investigation of intra-brain processes (e.g., cognitive and emotional regulation) and inter-brain synchrony (e.g., neural alignment during social interactions).
• Tasks and Measures: Participants will complete tasks designed to assess social bonding, emotional regulation, and cognitive processing. Tasks include structured paradigms (e.g., music perception tasks and flanker task) and naturalistic social interactions. These are complemented by self-report measures assessing mood, social closeness, and perceptions of the interaction.
• Randomization and Counterbalancing: The order of alcohol versus control sessions will be randomized across participants to control for carryover effects.

Outcome Measures:

1. Neurophysiological Outcomes:

   Intra and Inter Brain Coupling (IBC):

   • Intra brain synchrony (within-subject): Coherence or phase-locking between brain regions within the same participant, compared across sober versus intoxicated states.
   • Inter brain synchrony (between-subject): Synchronization metrics (e.g., inter subject PLV, inter subject correlation) between paired participants, assessed separately in sober and intoxicated conditions

   Event Related Potentials (ERP):

   • Amplitudes and latencies of task-related ERP components, specifically Feedback Related Negativity (FRN), measured both for the operating ("player") and observing ("observer") participant, with comparisons across sobriety conditions

2. Behavioral and Psychological Outcomes:

   Self-reported mood and social bonding assessed pre- and post-interaction using validated measures such as the Inclusion of Other in Self Scale and the Biphasic Alcohol Effects Scale.

   Observational coding of nonverbal behaviors (e.g., facial expressions, body language) during dyadic interactions.

3. Drinking Behavior:

Longitudinal self-reports of drinking patterns and alcohol-related outcomes.

• Study Type: Interventional
• Enrollment (Estimated): 200
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Catharine E Fairbairn, Ph.D.; Phone Number: 217 300 5850; Email: cfairbai@illlinois.edu

Study Locations

• United States
  • Illinois
    • Champaign, Illinois, United States, 61820
      • Recruiting
      • University of Illinois Urbana-Champaign
      • Principal Investigator: Catharine Fairbairn, Ph.D.
      • Contact: Catharine Fairbairn, Ph.D.; Phone Number: 217 300 5850; Email: cfairbai@illlinois.edu
    • Champaign, Illinois, United States, 61820
      • Not yet recruiting
      • University of Illinois at Urbana Champaign
      • Contact: Catharine E Fairbairn, Ph.D.; Phone Number: 2173005850; Email: cfairbai@illlinois.edu

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Between the ages of 21 and 30
• Regularly consumes alcohol

Exclusion Criteria:

• History of adverse reaction to the amount of beverage employed in the study
• Have a history of major problems associated with alcohol
• Take medications that could adversely interact with alcohol
• Have medical conditions that contraindicate alcohol administration
• Individuals with a history of skull fractures or who indicate discomfort with EEG procedures used
• Female participant is pregnant or trying to become pregnant

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Alcohol beverage administration	Drug: Alcohol beverage; This intervention involves the administration of an alcohol beverage (vodka mixed with juice or soda) in a controlled laboratory setting, targeting a blood alcohol concentration (BAC) of 0.08%. The alcohol is consumed over a 36-minute period in three equal parts.
Other: Control condition - non alcoholic beverage	Other: Control - non alcoholic beverage; This intervention involves the administration of a non-alcoholic control beverage in a controlled laboratory setting. The beverage is matched in volume and palatability to the alcohol condition but co

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Ambulatory Drinking	Drinking behavior assessed outside the laboratory using ambulatory assessment	14 days
Longitudinal Drinking Problems	Drinking assessed at longitudinal follow-up	Up to 24 months post-baseline
Inter-brain entrainment	Synchronization metrics (e.g., inter-subject PLV, inter-subject correlation) between paired participants, assessed separately in sober and intoxicated conditions	During active laboratory beverage manipulation exposure (during or immediately after beverage administration, at which time participants in the alcohol condition will register a positive BAC)
Intra-brain entrainment	The comparison of EEG signal synchronization within the same participant across the alcohol and non-alcohol conditions, reflecting intra-brain activity changes due to alcohol consumption during the hyperscanning task.	During active laboratory beverage manipulation exposure (during or immediately after beverage administration, at which time participants in the alcohol condition will register a positive BAC)
Event-Related Potentials (ERP)	Feedback-Related Negativity (FRN), measured both for the operating ("player") and observing ("observer") participant, with comparisons across sobriety conditions	During active laboratory beverage manipulation exposure (during or immediately after beverage administration, at which time participants in the alcohol condition will register a positive BAC)

Collaborators and Investigators

• Sponsor: University of Illinois at Urbana-Champaign

Study record dates

Study Major Dates

• Study Start (Actual): August 9, 2025
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): May 1, 2028

Study Registration Dates

• First Submitted: August 9, 2025
• First Submitted That Met QC Criteria: August 9, 2025
• First Posted (Actual): August 15, 2025

Study Record Updates

• Last Update Posted (Estimated): August 29, 2025
• Last Update Submitted That Met QC Criteria: August 22, 2025
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Mental Disorders; Substance-Related Disorders; Chemically-Induced Disorders; Drinking Behavior; Alcohol-Related Disorders; Behavior; Alcoholism; Alcohol Drinking; Alcoholic Intoxication; Binge Drinking; Organic Chemicals; Alcohols; Ethanol
• Other Study ID Numbers: 2R01AA025969-01 (U.S. NIH Grant/Contract); 2R01AA025969 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Data is being shared on the National Institute of Mental Health Data Archive

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No