Documentary to Encourage Plant-based Eating

Randomized Controlled Trial of a Documentary to Encourage Plant-based Eating

This study will assess whether watching a documentary video about the health, environmental, and ethical consequences of eating meat and animal products reduces participants' self-reported intake of these items.

Study Overview

• Status: Completed
• Conditions: Eating Behavior
• Intervention / Treatment: Behavioral: Documentary; Behavioral: Control

Detailed Description

See detailed preregistration: https://osf.io/xrckh/registrations

• Study Type: Interventional
• Enrollment (Actual): 650
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Palo Alto, California, United States, 94304
      • Maya Mathur

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Participant is currently located in the United States
• Participant is at least 18 years old

Exclusion Criteria:

• Participant is located outside the United States
• Participant is less than 18 years old

Study Plan

How is the study designed?

Design Details

• Primary Purpose: OTHER
• Allocation: RANDOMIZED
• Interventional Model: PARALLEL
• Masking: NONE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Intervention; See detailed preregistration: https://osf.io/xrckh/registrations	Behavioral: Documentary; A 20-minute documentary about the health, environmental, and animal welfare consequences of eating meat and animal products
SHAM_COMPARATOR: Control; See detailed preregistration: https://osf.io/xrckh/registrations	Behavioral: Control; A 20-minute unrelated video (a motivational talk entitled "Listening to shame")

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total meat and animal product consumption	Self-reported meat and animal product consumption (ounces consumed over the past week)	Consumption over the 1-week time frame spanning approximately 1 week to 2 weeks after baseline data collection

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total meat consumption	Self-reported meat consumption (ounces consumed over the past week)	Consumption over the 1-week time frame spanning approximately 1 week to 2 weeks after baseline data collection
Total animal product consumption	Self-reported animal product consumption (ounces consumed over the past week)	Consumption over the 1-week time frame spanning approximately 1 week to 2 weeks after baseline data collection
Consumption of each of 8 individual categories of meats and animal products	Self-reported consumption (ounces consumed over the past week)	Consumption over the 1-week time frame spanning approximately 1 week to 2 weeks after baseline data collection
Total consumption of selected, healthy plant-based foods (ounces consumed over the past week)	Self-reported consumption (ounces consumed over the past week)	Consumption over the 1-week time frame spanning approximately 1 week to 2 weeks after baseline data collection

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Perceived importance of health	A single Likert item adapted from Heckler (2010), ranging from 1 to 6, with higher scores representing greater perceived importance. The exact text is provided in detailed preregistration: https://osf.io/xrckh/registrations.	2 weeks after baseline data collection
Perceived importance of environmental sustainability	A single Likert item adapted from Heckler (2010), ranging from 1 to 6, with higher scores representing greater perceived importance. The exact text is provided in detailed preregistration: https://osf.io/xrckh/registrations.	2 weeks after baseline data collection
Perceived importance of animal welfare	A single Likert item adapted from Heckler (2010), ranging from 1 to 6, with higher scores representing greater perceived importance. The exact text is provided in detailed preregistration: https://osf.io/xrckh/registrations.	2 weeks after baseline data collection
Speciesism	Caviola et al.'s (2019) Speciesism Scale, consisting of 6 Likert items each ranging from 1 to 7. After reverse-coding, a higher score on the sum of the items (ranging from 6 to 42) represents greater speciesism. The exact text for all items is provided in detailed preregistration: https://osf.io/xrckh/registrations.	2 weeks after baseline data collection
Interest in animal welfare activism and reform	2 items modified from Corning et al.'s (2002) Activism Orientation Scale as well as 3 novel items, consisting in total of 5 items each ranging from 1 to 7. A higher score on the sum of the items (ranging from 5 to 35) represents greater interest in activism and reform. The exact text for all items is provided in detailed preregistration: https://osf.io/xrckh/registrations.	2 weeks after baseline data collection
Social dominance orientation	Ho et al.'s (2015) 8-item Social Dominance Orientation [SDO(7)] scale, consisting in total of 5 items each ranging from 1 to 7. After reverse-coding, a higher score on the sum of the items (ranging from 8 to 56) represents greater interest in activism and reform. The exact text for all items is provided in detailed preregistration: https://osf.io/xrckh/registrations.	2 weeks after baseline data collection

Collaborators and Investigators

• Sponsor: Stanford University
• Investigators: Principal Investigator: Maya B Mathur, PhD, Stanford University

Publications and helpful links

Helpful Links

• Future location of data, code, and materials
• Detailed preregistration

Study record dates

Study Major Dates

• Study Start (ACTUAL): August 26, 2020
• Primary Completion (ACTUAL): September 7, 2020
• Study Completion (ACTUAL): December 31, 2020

Study Registration Dates

• First Submitted: July 31, 2020
• First Submitted That Met QC Criteria: August 5, 2020
• First Posted (ACTUAL): August 11, 2020

Study Record Updates

• Last Update Posted (ACTUAL): March 17, 2021
• Last Update Submitted That Met QC Criteria: March 15, 2021
• Last Verified: March 1, 2021

More Information

Terms related to this study

• Other Study ID Numbers: eatingveg

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All materials and analysis code required to reproduce all results will be made publicly available. All data except for participants' counties of residence (which is considered identifying information) will also be made publicly available.
• IPD Sharing Time Frame: Immediately upon journal acceptance or earlier if possible given embargo policies.
• IPD Sharing Access Criteria: Public availability
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE

Drug and device information, study documents

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