Analyzing the Effectiveness of a Meatless Monday Intervention on Meat Consumption and Associated Pro-Environmental Spillover Behavior Throughout the Week

Undergraduate Research Thesis

Presented in partial fulfillmen t of the requiremen ts f or graduation with research dis tinction in the undergraduate c olleges of The Ohio St ate University

Stephen Mattson The Ohio St ate Univ ersity April 2020

Project Advisor: Dr . Nic ole Sin tov, School of E nvironment and Natural R esources

Abstract

A global r eduction in mea t c onsumption has been iden tified as a critic al s trategy t o mitig ate the impacts of clima te chang e, as w ell as t o main tain sus tainable land and w ater s ystems. Se veral forms of in terventions ha ve pr omoted r educed mea t c onsumption, with v arying success r ates. One such s trategy is Mea tless Monda y (MM), a c ampaign enc ouraging ab stention fr om mea t consumption on Monda ys f or en vironmental and health r easons. Lit tle e xperimental r esearch has been c onducted r egarding the e ffectiveness of the c ampaign, or of mea t c onsumption reduction in terventions g enerally. Another ar ea w arranting additional r esearch is tha t of beha vioral spillo ver, especially as related t o pr o-environmental beha vior (PEB). Beha vioral spillo ver has been de fined as the e ffect of an in tervention on sub sequent beha viors not t argeted b y the in tervention (e. g., a household recycling in tervention motiv ating incr eased ener gy c onservation r ates). This s tudy addr essed such r esearch g aps b y t esting whe ther an in tervention enc ouraging participation in MM w ould lead t o signific antly r educed mea t c onsumption on Monda y and during the r est of a giv en w eek, as w ell as t o higher perf ormance r ates of other PEBs during tha t week (i.e., beha vioral spillo ver). W e h ypothesized tha t each e ffect w ould be ob served. The sample c onsisted of s tudents enr olled in OSU under graduate c ourses (n = 111). Participants w ere r andomly assigned in to c ontrol and e xperimental gr oups, and c ompleted a baseline sur vey assessing mea t c onsumption and PEBs perf ormed, among other v ariables. The experimental gr oup also r eceived a digit al fly er enc ouraging participa tion in MM. Both gr oups then c ompleted f ood diaries assessing mea t c onsumption f or one w eek, and a f ollow-up sur vey assessing PEBs perf ormed and other f actors during tha t w eek. Subsequent analy ses led t o all thr ee h ypotheses being r ejected. In f act, the e xperimental group r eported higher w eek-level mea t c onsumption, pot entially due t o f ailed baseline randomization. Futur e r esearch is w arranted t o iden tify f actors tha t ma y mak e mea t consumption r eduction in terventions mor e e ffective, and t o de termine c onditions under which pro-environmental beha vioral spillo ver ma y occur .

Introduction

Study Objectives

This s tudy aimed t o addr ess r esearch g aps r elated t o the e ffectiveness of mea t c onsumption reduction in terventions, specific ally the Mea tless Monda y c ampaign, in motiv ating r educed mea t consumption f or the purposes of en vironmental bene fit. It also in vestigated the phenomenon of pro-environmental beha vioral spillo ver, assessing the e xtent t o which an in tervention pr omoting Meatless Monda y c an lead t o other pr o-environmental beha viors not t argeted b y the intervention.

Literature R eview

Environmental Impacts of Meat Consump tion and Die t

Significant r eduction in gr eenhouse g as emissions (GHGes) ar e necessar y if w e ar e t o limit the global a verage t emperature incr ease t o w ell belo w 2 °C , the g oal se t f orth in the P aris Agreement (Schleussner e t al., 2016). T o achie ve these r eductions, it is critic al tha t w e not only transform ener gy and tr ansportation in frastructure, as is c ommonly pr oposed, but also our die ts, so as t o decr ease c onsumption of mea t and other animal pr oducts. Indeed, in its 2018 r eport on global w arming, the IPCC iden tified the r eduction of mea t c onsumption as an import ant s trategy to r educe emissions and thus mitig ate the impacts of clima te chang e (de Coninck e t al., 2018). It has been es timated tha t appr oximately 14.5% of global GHGes c an be a ttributed t o the livestock sect or annually , amoun ting t o o ver 7 gig atons of C O2 -equiv alent (Gerber e t al., 2013). Among the man y r easons f or this sub stantial c arbon f ootprint is the f act tha t mea t pr oduction is highly ine fficient, as plan t ma terial is f ed t o liv estock, which is then f ed t o humans, r ather than feeding plan t ma terial dir ectly t o humans. Indeed, a 2013 s tudy c alculated tha t an a verage of 27 lbs of plan t biomass ar e r equired f or e very pound of mea t (Smith e t al., 2013). This ine fficiency means tha t signific antly gr eater f ossil fuel ener gy inputs ar e r equired f or animal pr otein pr oduction than ar e r equired f or plan t pr otein pr oduction, a t an es timated r atio

3 of 11 t o 1 (Pimen tel & Pimen tel, 2003). The pot ential f or r eduction in GHGes b y w ay of decreased mea t c onsumption is ther efore signific ant. In an analy sis of the clima te chang e impacts of global die tary chang e, it w as f ound tha t tr ansitioning t oward mor e plan t-based die ts that align with s tandard die tary guidelines c ould r educe f ood-related GHGes b y up t o 70%, when compared t o a 2050 r eference scenario (Springmann e t al., 2016). However, it is also import ant t o not e tha t r educed mea t c onsumption ma y addr ess a hos t of other en vironmental challeng es outside of global w arming and GHGes, including land degradation, biodiv ersity loss, and w ater sc arcity, among other s. The v ast ar ea r equired f or pasture mak es mea t pr oduction highly land-in tensive, with pas ture c overing mor e than double the ar ea of global ice- free land tha t cr opland c overs, and with a thir d of tha t cr opland being used solely f or f eed cr ops (F AO, 2011). This r atio of land usag e is particularly pr oblematic in the Amazon r ainforest, wher e it has been es timated tha t o ver 75% of all de forested lands ha ve been converted t o liv estock pas ture and f eed cr op pr oduction (Nep stad, Stickler , & Soar es-Filho, 2008). As a major sour ce of both biodiv ersity and c arbon seques tration, the Amaz on r ainforest must be pr eserved t o mitig ate further en vironmental damag e, which c an be achie ved in part b y reducing mea t c onsumption, thus ob viating the need t o c onvert mor e r ainforest t o pas ture. Meat pr oduction is also highly w ater-intensive, due t o the signific ant w ater f ootprints of f eed crops and the liv estock itself . 29% of the t otal w ater f ootprint of the global agricultur al sect or has been a ttributed t o animal pr oduction, c omprising o ver 15% of global fr eshwater use. Furthermore, it has been es timated tha t o ver 1,800 g allons of w ater ma y be r equired t o pr oduce a single pound of bee f, and o ver 500 g allons of w ater f or a single pound of chick en, as c ompared to 115 g allons f or a pound of fruit and 39 g allons f or a pound of v egetables (Mek onnen & Hoekstra, 2010). When c onsidering these and other en vironmental impacts in ag gregate, it is e vident tha t a diet c omposed of f ewer animal pr oducts is mor e en vironmentally sus tainable, while of fering f ar greater pot ential t o addr ess global f ood security challeng es (Smith e t al., 2013). Indeed, in a comparison of the en vironmental impacts of v egetarian and non vegetarian die ts in Calif ornia, it was f ound tha t non vegetarian die ts r equired 2.9 times mor e w ater, 2.5 times mor e primar y energy, 13 times mor e f ertilizer, and 1.4 times mor e pes ticides than tha t of v egetarian die ts (Marlow e t al., 2009). Additionally , in a lar ger r eview of 63 s tudies r elated t o the adop tion of

4 sustainable die ts, the lar gest en vironment bene fits, including GHGes, land use, and w ater use, were witnessed in those die ts tha t mos t r educed the amoun t of animal-based f oods c onsumed (e.g., pesc atarian, v egetarian, and v egan die ts) (Alek sandrowicz e t al., 2016).

The Meatless Monday Mo vement

In ligh t of these en vironmental impacts, man y s trategies ha ve been pr oposed t o enc ourage consumers t o r educe their per sonal mea t c onsumption. One such s trategy is Mea tless Monda y. Launched in 2003, Mea tless Monda y is a global initia tive with a simple messag e: one da y per week, don’t ea t mea t. The mo vement w as f ounded in c ollaboration with the Cen ter f or a Liv able Future a t the Johns Hopkins Bloomber g School of Public Health, as one of its Health y Monda y initiatives, which enc ourage c onsumers t o mak e healthier decisions a t the beginning of each week. The mo vement has the g oal of f acilitating a 15% r eduction in mea t c onsumption f or both environmental and health r easons (Clark, 2016). The mo vement f ocuses on Monda y in lar ge part due t o the “fr esh s tart e ffect,” which r efers to the phenomenon tha t people ar e mor e lik ely t o eng age in aspir ational beha viors f ollowing temporal landmark s, such as the beginning of a ne w w eek. Beha vioral r esearchers a t the University of P ennsylvania f ound e vidence f or this e ffect among such beha viors as die ting, gym attendance, and the cr eation of c ommitment c ontracts (Dai, Milkman, & Riis, 2014). Other studies f ound tha t smoking cessa tion Google sear ch queries on Monda y w ere 25% higher than the c ombined mean f or T uesday thr ough Sunda y (A yers, Althouse, & Johnson, 2014a), and tha t health-related queries w ere the highes t on Monda y and T uesday (A yers, Althouse, & Johnson, 2014b), thus pr oviding e vidence f or this e ffect. Indeed, while some people r eport tha t Monda y is “a da y t o dr ead,” man y people see Monda y positiv ely, vie wing the da y as an opportunity f or a “fresh s tart” and t o “ get their acts t ogether” (Da ta Decisions Gr oup, 2017). Other s tated r easons for f ocusing on Monda y include the need t o dis tance the mea tless da y fr om Frida y, which is traditionally alr eady a mea t-free da y among Ca tholics and Orthodo x Chris tians, and the idea tha t weekly r eminders t o r estart health y habits ma y enc ourage success (Clark, 2016). There is e vidence tha t a wareness of Mea tless Monda y has gr own mark edly in the Unit ed States o ver time. Acc ording t o a na tionally r epresentative sample of o ver 1,000 Americ an adults,

5 over 50% of Americ ans w ere a ware of Mea tless Monda y b y 2011 (F GI R esearch, 2011). A follow-up s tudy in 2012 f ound tha t of those a ware of Mea tless Monda y, 62% r eportedly had attempted t o inc orporate the mo vement in to their w eekly r outines, and 40% r eportedly had incorporated mor e mea tless meals in to their die ts during the r est of the w eek as a r esult (F GI Research, 2012). Ho wever, it should be not ed tha t this r esearch has not been peer -reviewed and thus should not be c onsidered as cr edible as c omparable peer -reviewed lit erature. Indeed, ther e does not appear t o be an y e xisting peer -reviewed r esearch analy zing r esponses t o Mea tless Monday messaging in an empiric al, quan titative manner , a not able r esearch g ap t o be addressed. Furthermore, while numer ous sur veys ha ve been adminis tered r egarding the g eneral effectiveness of Mea tless Monda y (e. g., Leidig , 2012), it does not appear tha t an y e xperimental research has been c onducted t o ascert ain the specific impacts tha t the Mea tless Monda y campaign has on actual individual mea t c onsumption beha vior (e. g., in the f orm of f ood diaries). This r esearch g ap is due in part t o the inher ent challeng es of accur ately tr acking mea t consumption and of c ausally a ttributing such beha vior t o Mea tless Monda y messaging (Chan & Ramsing, 2017). Indeed, the v ast majority of e xisting r esearch r elated t o Mea tless Monda y has been limit ed t o qualit ative descrip tions of the mo vement’s origins (e. g., Clark, 2016), examinations of its pot ential g eneralized r ole in media ting clima te chang e (e. g., Do yle, 2011), and pr actical tip s f or mor e e ffective implemen tation in specific dining se ttings (e. g., Chan & Ramsing, 2017). Ther efore, a mor e quan titative e xamination of Mea tless Monda y b y means of an experimental design is w arranted, as will be c onducted in this s tudy.

Consumer A ttitudes T owards Meat Consump tion

It is import ant also t o not e tha t while a wareness of Mea tless Monda y has lik ely gr own o ver time, c onsumer a ttitudes t owards e fforts t o r educe mea t c onsumption r emain highly v ariable. One c onsistent finding , ho wever, is tha t c onsumers g enerally under estimate the en vironmental impacts of liv estock pr oduction (V anhonacker, V an Loo , & Gellynck, 2013). A 2011 s tudy f ound that c onsumers belie ve tha t, among pot ential ec ological f ood c onsumption beha viors, a voiding excessive pack aging had the mos t signific ant pr o-environmental impact, wher eas r educing mea t

6 consumption and pur chasing or ganic f ood had the leas t impact (T obler, Visscher s, & Siegris t, 2011). Similarly , in f ocus gr oup discussions assessing public a ttitudes t owards the en vironmental impacts of mea t c onsumption, r esearchers f ound tha t participan ts e xhibited a signific ant lack of awareness of the associa tion be tween mea t c onsumption and clima te chang e, and a g eneral perception tha t per sonal mea t c onsumption beha vior pla ys only a minimal r ole in the global context of clima te chang e (Macdiarmid, Douglas, & Campbell, 2016). Additionally , a r ecent international sur vey f ound tha t while 83% of r espondents agr eed tha t human activity is contributing t o clima te chang e, only 30% per ceived mea t and liv estock pr oduction t o be a significant c ontributor (Baile y, Fr oggatt, & W ellesley, 2014). Furthermore, e vidence has sug gested tha t c onsumers ar e not primarily motiv ated b y environmental impact when f orming in tentions t o r educe mea t c onsumption. Ra ther, c onsumers may be mor e motiv ated b y health c onsiderations than b y en vironmental c onsiderations when choosing t o eng age in such beha vior (La tvala e t al., 2012). Lending further support t o this finding was a r ecent na tionally-representative sur vey of U .S. adults, which f ound tha t the mos t commonly cit ed r easons f or r educing mea t c onsumption w ere c ost and health, wher eas environmental and animal w elfare r easons w ere less in fluential (Ne ff, E dwards, & P almer, 2018). Perceived barrier s t o r educing mea t c onsumption ar e numer ous and v aried. In 2017, German researchers published a s ystematic me ta-analysis of r elevant s tudies, r evealing tha t a hos t of interrelated f actors function as barrier s t o r educing mea t c onsumption (St oll-Kleemann & Schmidt, 2017). Man y people lack suf ficient kno wledge of the c onsequences of high mea t consumption, or of the necessar y skills t o chang e one’ s die t, including mea tless c ooking skills. Others utiliz e denial and de fense mechanisms t o dis tance themselv es p sychologically fr om the potential beha vior chang e, or cit e a lack of a vailability of v egetarian op tions wher e the y shop or reside. Still other s main tain their curr ent r ates of mea t c onsumption due t o daily habits, a preference f or the t aste of mea t (Lea & W orsley, 2003), or financial c onsiderations, due in part t o economic sub sidies supporting the liv estock indus try and thus driving c onsumer prices do wn. Indeed, these f actors and other s w ork t ogether t o main tain a r elative s tatus quo of mea t consumption, with lar ge-scale in frastructure chang e needed t o f acilitate plan t-based ea ting on a broader sc ale (St oll-Kleemann & Schmidt, 2017).

Meat Consump tion R eduction In terventions

While mea t c onsumption r eduction in terventions r epresent a r elatively no vel ar ea of research in terest, multiple appr oaches ha ve been e xperimentally t ested, with mix ed r esults. F or example, man y such in terventions ha ve f ocused on r estructuring the ph ysical micro-environments tha t individuals enc ounter when making decisions r egarding mea t consumption. A r ecent s ystematic r eview of such in terventions f ound tha t this kind of ph ysical restructuring ma y help t o pr omote r educed demand f or mea t c onsumption, specific ally including those in terventions which r educed mea t ser ving portion siz es, pr ovided meal alt ernatives, or changed the sensor y pr operties of mea t (Bianchi e t al., 2018). The e ffectiveness of in formational and emotional messaging has also been e valuated in e xperimental se ttings, with the la tter in particular ha ving been associa ted with r educed mea t c onsumption in cert ain c ontexts (e. g., Carfona, Bert olotti, & Ca tellani, 2019). Many in terrelated f actors ma y c ontribute t o the success or f ailure of mea t c onsumption reduction in terventions. In a r ecent s tudy, it w as f ound tha t per ceived beha vioral c ontrol, attitudes, per sonal norms, and pr oblem-awareness all signific antly impact the phase of behavioral chang e (including pr e-decision, pr e-action, action, and pos t-action phases) an individual ma y ha ve achie ved when c onsidering r eductions in mea t c onsumption. Additionally , factors such as f emale g ender and incr eased educ ation w ere c orrelated with the pr obability of belonging t o a phase of beha vioral chang e, and the achie vement of higher such phases, respectively (W eibel, Ohnmach t, & Scha ffner, 2019). In another s tudy, a multic omponent intervention, the in formational c omponent (i.e., incr easing a wareness of the neg ative impacts of meat c onsumption) w as iden tified b y participan ts as mos t e ffective in leading t o r eductions in meat c onsumption, when c ompared t o social norm, f ear, and g oal-setting c omponents (Amiot, El Hajj Boutr os, & Sukhano va, 2018). P ast pur chasing e xperiences tha t w ere r ewarding t o consumers ma y also pr edict futur e pur chasing and c onsumption of sus tainable f oods, including those without mea t (V assallo, Sc alvedi, & Saba, 2015). Ho wever, e ven when e ffective, mea t reduction in terventions, particularly ones tha t enc ourage adher ence t o a “mea tless da y,” ar e not without their fla ws, as participan ts ma y r eplace mea t with incr eased c onsumption of pr oducts

8 that s till ha ve signific ant neg ative en vironmental impacts, such as eg gs (de Boer , Schösler , & Aiking, 2014). In spit e of these div erse findings, r esearch g aps s till r emain in r elation t o mea t c onsumption reduction in terventions g enerally, with lit tle r esearch ha ving been c onducted t o in vestigate the factors tha t ma y r ender them mor e or less e ffective (Amiot, El Hajj Boutr os, & Sukhano va, 2018). Thus, further e xperimental r esearch in vestigating mea t c onsumption r eduction in terventions is warranted.

Behavioral Spillo ver and Pro-E nvironmental Behavior

Another ar ea of in terest when c onsidering mea t c onsumption r eduction in terventions concerns the e ffects of such in terventions on other r elated beha viors, kno wn as beha vioral spillover. Beha vioral spillo ver, a phenomenon t o which man y dif ferent labels ha ve been historically been a ttached (Aus tin e t al., 2011), is a r elatively no vel ar ea of in terest within psychology and beha vioral science g enerally. It c an be br oadly de fined as an “ effect of an intervention on sub sequent beha viors not t argeted b y the in tervention” (T ruelove e t al., 2014), though de finitions ma y v ary. An e xample of beha vioral spillo ver migh t be the e ffect of a household ener gy c onsumption in tervention on r ecycling r ates. Both positiv e and neg ative spillover c an occur , with positiv e spillo ver r epresenting an incr ease in fr equency of the non-targeted beha vior, and neg ative spillo ver r epresenting a decr ease in fr equency. Within the context of the a forementioned e xample, incr eased r ecycling r ates as a r esult of the ener gy consumption in tervention w ould r epresent positiv e spillo ver, with decr eased r ecycling r ates representing neg ative spillo ver. Indeed, a signific ant ar ea of in terest within spillo ver r esearch r elates t o pr o-environmental behavior (PEB), as r esearchers and policymak ers seek t o under stand ho w positiv e spillo ver c an be utiliz ed t o cr eate mor e e ffective PEB in terventions, as w ell as ho w t o quan tify and minimiz e negative spillo ver e ffects associa ted with such in terventions. While a v ariety of PEBs ha ve been studied in r ecent y ears, no r esearch appear s t o ha ve been c onducted e xploring beha vioral spillover within the c ontext of Mea tless Monda y. Ques tions e xist as t o whe ther adop tion of Meatless Monda y c an lead t o positiv e spillo ver within the same beha vioral domain (e. g., ea ting

9 more or ganic f ood) or among other PEB domains (e. g, sorting r ecycling), or perhap s whe ther adoption of such a chang e ma y actually c ause neg ative spillo ver in r elation t o other PEBs. These intriguing ques tions will be addr essed in this s tudy.

Environmental Iden tity

There ha ve been numer ous in terrelated theor etical pa thways pr oposed tha t ma y c ontribute to spillo ver e ffects. In r egard t o this particular s tudy, one salien t mechanism r elates t o iden tity, specifically en vironmental iden tity. This theor etical pa thway r efers t o the idea tha t in terventions encouraging PEB ma y either s trengthen one’ s en vironmental iden tity (if the beha vior is adop ted), or w eaken it (if it is not adop ted), leading t o positiv e or neg ative spillo ver, r espectively. This pathway has r eceived a r elatively lar ge amoun t of scholarly a ttention and support when compared t o other pr oposed PEB spillo ver pa thways, and has been demons trated t o be a significant pr edictor f or se veral f orms of PEBs (Whitmar sh & O ’Neill, 2010). For e xample, in a r ecent s tudy of such beha viors, it w as f ound tha t a ttaching environmentalist labels t o individuals who perf ormed PEBs led t o incr eased r ates of positiv e spillover (Lac asse, 2016). This finding c an be e xplained in part b y c onsistency theor y, which not es that humans ha ve an in ternal desir e t o r educe c ognitive dissonance b y acting c onsistently with their belie f and iden tities (F estinger, 1957). This desir e t o a void inc onsistency has indeed been found t o be an import ant f actor in shaping pr o-environmental beha vior (Thøg ersen, 2004), as an individual with an es tablished en vironmental iden tity will seek t o beha ve in a manner c onsistent with being an en vironmentalist (V an der W erff, St eg, & K eizer, 2013), and vice v ersa. The iden tity e ffect does not function as a binar y in fluence on futur e PEBs, but r ather functions as a c ontinuum. The s trength with which a PEB signals tha t one is a pr o-environmental person has been demons trated t o in fluence the e ffect on one’ s en vironmental iden tity, with stronger signaling leading t o incr eased s trengthening in one’ s iden tity (V an der W erff, St eg, & Keizer, 2014). R elevant t o this s tudy, the e xtent t o which eng aging in Mea tless Monda y signals that one is a pr o-environmental per son ma y v ary based on multiple f actors, such as pas t mea t consumption beha vior and motiv ations f or eng aging in the c ampaign.

One particularly in triguing s tudy e xplored such iden tity e ffects within the c ontext of a mea t reduction pr ogram being implemen ted in a priv ate sect or c ompany, albeit with a r elatively small participant sample siz e ( n = 13). The s tudy w as based upon principles of iden tity pr ocess theor y, which seek s t o e xplain ho w people r espond t o chang es in their ph ysical and social en vironments, either c oping with such chang es or in tegrating them in to their iden tities. Using these ideas, the study pr oposed a c onceptual fr amework f or e xplaining ho w individuals ma y r eact t o the information of an en vironmental beha vior chang e in tervention (BCI), in r egards t o iden tity. Three dis tinct r esponse pa thways ar ose: in tegration, c ompartmentalization, and c onflict. Integration r eferred t o when the c ontent of the BCI bec ame mor e cen tral t o individuals, leading to s trengthening of en vironmental iden tity, c onsistent perf ormance of PEBs, and positive spillover. Compartmen talization r eferred t o when the c ontent of the BCI bec ame neither mor e or less cen tral t o individuals, leading t o separ ation of the beha vior fr om en vironmental iden tity, one-off beha vior, and a lack of spillo ver. Finally , c onflict (c onflict iden tities) r eferred t o when the content of the BCI bec ame less cen tral t o individuals, leading t o w eakening of en vironmental identity, r eactive beha vior, and negative spillo ver (V erfeuth e t al., 2019). This 2019 s tudy, while limit ed in sample siz e, is indeed r elevant t o the pr esent s tudy, as it proposed a fr amework of c onnecting en vironmentalist iden tity and beha vioral spillo ver within the c ontext of a mea t r eduction pr ogram, and mor e specific ally, pr oposed e xplanatory pa thways by which positiv e and neg ative spillo ver e ffects ma y occur (or lack ther eof). Ho wever, it should be not ed tha t the findings of this 2019 s tudy w ere g enerated primarily fr om qualit ative da ta, having been c ollected primarily fr om semi-s tructured in terviews, and a non-e xperimental s tudy design. Ther efore, the pr esent s tudy will inc orporate and e xpand upon the abo ve ideas, utilizing a mor e quan titative appr oach and an e xperimental design tha t will addr ess man y of the 2019 study’s limit ations.

Behavioral Dif ficulty

Another import ant f actor t o c onsider in r elation t o iden tity is tha t of beha vioral dif ficulty. This is bec ause per ceived beha vioral dif ficulty of an initial beha vior t argeted b y an in tervention has been sho wn t o in fluence the e xtent t o which iden tity is amplified, and thus the e xtent t o which spillo ver ma y occur . F or e xample, in a s tudy of charit able dona tions and hones ty,

11 researchers f ound tha t pr o-social iden tity w as s trengthened only when the initial charit able donations w ere per ceived t o be dif ficult, incr easing sub sequent hones ty, a f orm of positiv e spillover (Gnee zy e t al., 2012). Ho wever, s tudies of beha vioral dif ficulty also apply dir ectly t o environmental decision-making. Indeed, it has been pr oposed tha t initial beha viors r epresenting high per ceived beha vioral dif ficulty lead t o incr eased s trengthening of en vironmental iden tity, and thus incr eased r ates of positiv e spillo ver (T ruelove e t al., 2014). Support f or this e ffect w as found in a s tudy linking household c omposting, a per ceivedly dif ficult beha vior (T ruelove & Gillis, 2018), with positiv e spillo ver r elated t o ener gy and w aste pr evention (Sin tov, Geislar , & Whit e, 2017). However, T ruelove e t al. not ed tha t highly dif ficult initial beha viors ma y also lead t o neg ative spillover when perf ormed. In such situa tions, individuals ma y utiliz e the men tal appr oach kno wn as mor al licensing , which r efers t o the t endency t o use pas t g ood deeds t o jus tify futur e behaviors tha t ma y be mor e pr oblematic (Monin & Miller , 2001). F or e xample, if an individual engaged in the r elatively dif ficult action of ins talling ne w r ooftop solar panels, tha t individual may then f eel tha t it is mor e mor ally permissible t o ab stain fr om r ecycling, due t o the f act tha t he or she had alr eady c ompleted a dif ficult pr o-environmental beha vior. When c onsidering mea t c onsumption r eduction in terventions, beha vioral dif ficulty is quit e relevant, insof ar as r educing mea t c onsumption (or elimina ting it c ompletely on Monda ys) ma y be per ceived t o be a dif ficult initial beha vior. Inc onvenience, a ffinity f or mea t t aste, and pr otein consumption pr eferences ar e among the numer ous pot ential barrier s t o r educing mea t consumption, all of which ma y signific antly incr ease beha vioral dif ficulty, and, depending on ho w such dif ficulty is per ceived, ma y amplif y either positiv e or neg ative spillo ver e ffects.

Research Questions

Given the ur gent need f or the widespr ead adop tion of PEBs, the signific ant pro-environmental bene fits of r educed mea t c onsumption, and the man y unkno wns of mea t consumption r eduction in terventions, specific ally in r egard t o Mea tless Monda y, additional research is w arranted t o in vestigate the e ffectiveness of such in terventions. Furthermor e, while numerous pot entially in terrelated theor etical pa thways t o e xplain spillo ver within the c ontext of PEB ha ve been pr oposed, e vidence of actual spillo ver e ffects has been mix ed (Maki e t al., 2019). Additional r esearch is ther efore w arranted t o de termine the e xtent t o which pr o-environmental spillover beha vior ma y actually occur . In r esponse t o such needs, the f ollowing r esearch questions (R Qs) ar ose:

Will individuals who rec eive an in tervention enc ouraging participation in Meatless Monday …

RQ1 … c onsume signific antly less meat on Monday , relative t o no-in tervention c ontrols? RQ2… c onsume signific antly less meat during the res t of the week, relative t o c ontrols? RQ3 … perf orm signific antly more PEBs throughout the week, relative t o c ontrols?

Hypotheses

Based on a r eview of the lit erature, the f ollowing h ypotheses w ere made:

Individuals who rec eive an in tervention enc ouraging participation in Meatless Monday will...

H1: … c onsume signific antly less meat on Monday , relative t o no-in tervention c ontrols. H2: … c onsume signific antly less meat during the res t of the week, relative t o c ontrols. H3: … perf orm signific antly more PEBs throughout the week, relative t o c ontrols.

Methods

Participants

Recruitment and Inc entives

Students w ere r ecruited t o participa te in this r esearch s tudy fr om among f our semes ter-long undergraduate c ourses of fered in the School of En vironment and Na tural R esources (SENR) a t The Ohio St ate Univ ersity. These c ourses included ENR 2300 (“Socie ty and Na tural R esources”), RURLSOC 1500 (“In troduction t o Rur al Sociology ”), ENR 3200 (“En vironmental and Na tural Resources P olicy”), and ENR 3400 (“P sychology of En vironmental Pr oblems”). Students w ere of fered 1.25% e xtra cr edit t owards their c ourse gr ades in e xchange f or participation in the s tudy. Additionally , participan ts w ere en tered in to a r andomized r affle drawing t o win a $75 gift c ard t o a r etail loc ation of their choice, r eceiving one en try in to the drawing f or each f ood diar y c ompleted (up t o 7), thus incen tivizing participan ts t o c omplete f ood diaries (discussed in the “Pr ocedure” and “Measur es” sections).

Sample

A t otal of 159 individual participan ts c ompleted the initial sur vey. 4 participan ts w ere excluded fr om the sample due t o pr ocedural err ors (i.e., not including an iden tifier, err oneously completing sur vey measur es twice with c onflicting r esults). An additional 44 participan ts w ere omitted fr om the sample bec ause the y sa tisfied one or mor e of the f ollowing e xclusionary criteria: (1) iden tified as “v egan,” “v egetarian,” or “ almost v egetarian”- 31 participan ts; (2) completed f ewer than fiv e f ood diaries- 18 participan ts; (3) f ailed an a ttention check - 1 participant. Therefore, the final sample f or H1 and H2 w as n = 111, with 58 (52.3%) and 53 (47.8%) participants ha ving been r andomly assigned t o the c ontrol and e xperimental gr oups, respectively. It should be not ed tha t six participan ts who did not c omplete the f ollow-up sur vey were s till included in this sample of n = 111, due t o the f act tha t t esting f or H1 and H2 (i.e., mea t

14 consumption r ate on Monda y and thr oughout the r est of the w eek) did not r equire c ompletion of the f ollow-up sur vey. However, bec ause t esting f or H3 (i.e., r ate of PEBs perf ormed thr oughout the w eek) did require c ompletion of the f ollow-up sur vey, these six participan ts w ere e xcluded fr om the H3 sample. The sample f or H3 ther efore w as n = 105, with 57 (54.3%) and 48 (45.7%) participan ts having been r andomly assigned t o the c ontrol and e xperimental gr oups, r espectively.

Demographics

Demographics w ere c omputed f or the lar ger sample ( n = 111). The mean ag e w as 20.5 y ears old, with participan t ag es r anging fr om 18 t o 34 y ears old. An independen t samples t -test (t (108.6) 1 = 1.44; p = .152) a ffirmed tha t mean ag es did not dif fer signific antly be tween c ontrol ( x ̄ = 20.8, σ = 2.8) 2 and e xperimental ( x̄ = 20.1, σ = 2.4) gr oups. In r egards t o g ender, 33 (29.7%) participan ts iden tified as “male," 76 (68.5%) as “f emale," and 2 (1.8%) as “ other”/non-binary . A chi-squar e t est a ffirmed tha t g ender dis tribution did not differ signific antly be tween e xperimental and c ontrol gr oups ( χ 2 = 2.59; p = .274). Racially, participan ts w ere ask ed t o iden tify as one or mor e of the f ollowing op tions: “whit e,” “black or Afric an Americ an,” “Na tive Americ an or Alask a na tive,” “ Asian,” “Na tive Ha waiian or Pacific Islander ,” or “ other.” 95 (85.6%) participan ts iden tified as whit e only , 6 (5.4%) as Asian only, and 10 (9.0%) as mix ed r ace. The r esponses w ere ther efore r ecoded in to thr ee c ategories (white only = 1, Asian only = 2, and mix ed r ace = 3) t o r eflect these dif ferences. Aft er r ecoding, a chi-square t est a ffirmed tha t r acial dis tribution did not dif fer signific antly be tween e xperimental and c ontrol gr oups ( χ 2 = 1.11; p = .575). Regarding fields of s tudy, 58 (52.3%) participan ts w ere pur suing major s with either the w ord “environment” or “ environmental” in the title, with man y other s pur suing r elated fields of s tudy within SENR, including “f orestry, fisheries, & wildlif e,” and “na tural r esource manag ement." However, ther e w ere also a number of participan ts pur suing major s in v astly unr elated fields,

1 For all independent samples t-tests conducted in this study, equal variances between samples were not assumed. This led to degrees of freedom (the value within the parentheses) being computed as a decimal value for each such test, as a feature of the statistical software being used (IBM SPSS Statistics). 2 For this study, the symbols x ̄ and σ represent sample mean and standard deviation, respectively.

15 including c omputer science, music, nur sing, politic al science, and mechanic al engineering. The responses w ere ther efore r ecoded in to a ne w binar y v ariable, “major within SENR, ” with responses of 1 r epresenting participan ts who r eported pur suing a t leas t one major within SENR, and of 0 r epresenting participan ts who did not. An independen t samples t -test a ffirmed tha t the proportion of participan ts pur suing major s within SENR did not dif fer signific antly be tween treatment gr oups ( t (106.5) = .478, p = .633). Politically, 74 (66.7%) iden tified as either “v ery liber al,” “liber al,” or “ somewhat liber al,” with only 19 (17.1%) iden tifying as either “v ery c onservative,” “ conservative,” or “ somewhat conservative” and 18 (16.2%) iden tifying as “neither liber al nor c onservative” and iden tifying as either “v ery c onservative,” “ conservative,” or “ somewhat c onservative.” A chi-squar e t est affirmed tha t dis tribution of politic al a ffiliation did not dif fer signific antly be tween e xperimental and c ontrol gr oups ( χ 2 = 5.10; p = .531). As f or par ental educ ation, 86 (77.5%) participan ts r eported ha ving a t leas t one par ent who has c ompleted a 4- year c ollege degr ee or higher , with only 4 (3.6%) r eporting ha ving par ent(s) who did not c omplete an y f orm of c ollege educ ation (with the other 21 (18.9%) r eporting ha ving parent(s) who ha ve c ompleted “ some c ollege/associate’s degr ee”). A chi-squar e t est a ffirmed that dis tribution of par ental educ ation did not dif fer signific antly be tween tr eatment gr oups ( χ 2 = 3.00; p = .391). In r egards t o self -reported die tary pa tterns3 , outside of the 44 alr eady e xcluded fr om the sample, 61 (55.0%) participan ts iden tified as “ omnivores,” 8 (7.2%) as “pesc o-vegetarians 4,” and 42 (37.8%) “part -time v egetarians.” A chi-squar e t est a ffirmed tha t dis tribution of self -reported dietary beha vior did dif fer signific antly be tween c ontrol and e xperimental gr oups ( χ 2 = 8.98; p = .011), r eflecting a lar ger pr oportion of self -reported omniv ores in the e xperimental gr oup. The distribution is depict ed on the f ollowing pag e, in t able 1.

3 A detailed description of how these self-reported dietary patterns were assessed is included in the “Measures” section. 4 Pesco-vegetarians were included in the sample because fish is included in our definition of meat (i.e., “animal flesh that is consumed as food, including chicken, beef, pork, fish, other seafood, etc.)

Table 1 Comparison be tween T reatment Group s of Self -Reported Die tary Behaviors

Procedure

For r ecruitment, c ooperating f aculty member s dis tributed r ecruitment fly ers (see Appendix A) t o s tudents electr onically via digit al c ourse pla tforms. A member of the r esearch t eam then visited each of the f our classes in per son t o e xplain the c omponents of the enr ollment pr ocess and t o ans wer ques tions about the s tudy. Studen ts who w ere in terested in the s tudy click ed a link on the r ecruitment fly er t o a baseline sur vey hos ted on the electr onic pla tform Qualtrics, where the y w ere able t o digit ally sign a c onsent f orm and begin participa tion in the s tudy. The y were able t o do this a t an y time be tween Thur sday a t 8 A .M. and Sunda y a t 5 P .M. on a giv en week5 . The r est of the s tudy w as also c onducted electr onically. When s tudents beg an participa tion in the s tudy, the y w ere fir st r andomly assigned in to experimental and c ontrol gr oups via Qualtrics. The y all then c ompleted a brie f baseline sur vey, which t ook appr oximately 5-10 minut es. This sur vey assessed le vels of mea t c onsumption, baseline r ate of PEBs perf ormed, and other p sychological v ariables r elated t o mea t c onsumption, as w ell as demogr aphics. F or all mea t-related ques tions, mea t w as de fined as “ animal flesh tha t is c onsumed as flesh, including chick en, bee f, pork, fish, other sea food, e tc.”

5 This specific enrollment time range, and each following time range, was enforced via a feature of Qualtrics that allows the study administrator to limit survey responses to specific times.

At the end of the sur vey, the e xperimental gr oup also r eceived an in tervention in the f orm of a digit al fly er enc ouraging participa tion in Mea tless Monda y (see Appendix B). This fly er aimed t o prime en vironmental iden tity, incr ease a wareness of the en vironmental impacts of mea t production, activ ate social norms 6 , and decr ease per ceived beha vioral dif ficulty, with the ultimate g oal of pr omoting decr eased mea t c onsumption on Monda y. These fly er aims w ere selected bec ause, in the lit erature r eview, each of the f our beha vioral f actors w ere f ound t o ha ve been associa ted with r educed mea t c onsumption, pr o-environmental beha vior, and/ or positiv e spillover beha vior in v arying c apacities. Ther efore, it w as an ticipated tha t these f actors, when presented c ollectively, w ould be a t leas t moder ately e ffective in motiv ating individuals t o participate in Mea tless Monda y, as w ell as t o eng age in positiv e pr o-environmental spillo ver behavior during the r est of the w eek. After r eading this fly er, participan ts in the e xperimental gr oup only w ere ask ed about their relationship t o the Mea tless Monda y mo vement, including prior a wareness of the mo vement, past participa tion r ates, and futur e participa tion in tentions. On the Sunda y e vening immedia tely f ollowing c ompletion of the baseline sur vey, participan ts in both gr oups r eceived an email with ins tructions s tating tha t the y w ould be emailed individual links t o online f ood diaries each morning of the upc oming w eek (Monda y thr ough Sunda y, se ven separate emails) and tha t the y w ould ha ve 48 hour s t o c omplete each daily en try be fore the link expired, so as t o incr ease r eporting accur acy of the f ood c onsumed. F or e xample, Monda y’s f ood diary, emailed t o participan ts a t 8 A .M. Monda y morning , w ould ha ve t o be c ompleted be fore 8 A.M. W ednesday morning. The diaries w ere t o be emailed in the morning so tha t participan ts would ideally ha ve the op tion of c ompleting the r elevant portion of each f ood diar y en try immediately a fter each individual meal w as c onsumed (e. g., documen ting wha t w as ea ten f or breakfast immedia tely a fter br eakfast). Additionally, the Sunda y email r eminded participan ts tha t c ompletion of each f ood diar y entry earned them an additional en try in to the a forementioned dr awing f or a $75 gift c ard. Finally, f or the e xperimental gr oup only , the Sunda y e vening email c ontained a r eminder about the opportunity t o participa te in Mea tless Monda y the ne xt da y.

6 A description of the role social norms may play in motivating PEB is included in Appendix E.

Following this Sunda y e vening email, both gr oups r eceived the e xact same tr eatment, starting with the se ven daily f ood diaries. These daily f ood diaries w ere v ery brie f and simple in nature, and w ere es timated t o t ake a t otal of only 2-3 minut es t o c omplete each da y (see Appendix C). Finally, on Monda y morning of the f ollowing w eek (the w eek a fter the fir st Monda y f ood diary link w as sen t), each participan t w as emailed a brie f f ollow-up sur vey (5-10 minut es), and was ag ain giv en 48 hour s t o c omplete it. This sur vey assessed the same v ariables as did the baseline sur vey, with the e xception of demogr aphics and ques tions r elated t o Mea tless Monda y for the e xperimental gr oup.

Measures

The baseline and f ollow-up sur veys assessed the f ollowing f actors: (1) demogr aphics- baseline only; (2) curr ent mea t c onsumption beha vior- baseline only; (3) prior a wareness of Meatless Monda y- baseline/ experimental gr oup only; (4) pas t eng agement/future in tention t o engage in Mea tless Monda y- baseline/ experimental gr oup only; (5) r ate of PEBs perf ormed o ver the c ourse of a w eek; (6) a wareness of the en vironmental impacts of mea t pr oduction; (7) environmental iden tity; (8) per ceptions r egarding ab stention fr om mea t c onsumption (including perceived beha vioral dif ficulty); and (9) c ognitive accessibility of en vironmental f actors associated with die t. Measur es used t o assess these f actors ar e described belo w.7 To assess curr ent mea t c onsumption beha vior (baseline only), tw o measur es w ere adap ted from pr evious s tudies (Mullee e t al., 2017; Cor dts, Nitzk o, and Spiller , 2014). The fir st, used as an exclusionary crit erion, assessed self -reported die tary pa tterns b y asking participan ts t o “indic ate of the f ollowing die tary pa tterns mos t closely r epresents y our curr ent die t,” with the f ollowing options: (1) v egan- “no animal pr oducts”; (2) v egetarian- “no mea t or fish”; (3) almos t vegetarian- “ eating mea t or fish only on e xceptional occ asions; (4) part -time v egetarian- “ eating meat or fish a f ew times a w eek”; (5) pesc o-vegetarian- “no mea t but ea ting fish”; and (6) omnivore- ea ting mea t or fish on a daily basis or not in tentionally ab staining fr om mea t or fish.

7 Factors 6-9 were not analyzed in this study for the specific purposes of evaluating H1-H3. Therefore, descriptions of these measures are included in the appendix. Demographics are described in the “Participants” section.

The sec ond ask ed participan ts “within the las t se ven da ys, ho w oft en did y ou ea t mea t…” f or breakfast, lunch, dinner , and snack(s), with op tions r anging fr om 0 t o 7 da ys f or each meal. F or example, a r esponse of “3 da ys” f or lunch w ould indic ate tha t, during the las t w eek, the participant c onsumed mea t-containing lunches thr ee times. A ne w v ariable, “baseline meat-containing meals per w eek,” w as thus c alculated b y summing the t otal r eported meat-containing meals fr om each of br eakfast, lunch, dinner , and snack(s). To assess the e xperimental gr oup’s prior a wareness of Mea tless Monda y, participan ts w ere asked t o indic ate their le vel of a wareness of the mo vement prior t o r eading the fly er b y w ay of a five-point Lik ert sc ale, with 1 = “not a t all a ware” and 5 = “ extremely a ware.” To assess the e xperimental gr oup’s pas t eng agement in Mea tless Monda y, participan ts w ere asked t o ans wer “y es” or “no” t o the f ollowing ques tions: “ha ve y ou e ver participa ted in Meatless Monda y?” and “ did y ou participa te in Mea tless Monda y in the las t w eek?” T o assess the e xperimental gr oup’s futur e eng agement in tentions, participan ts w ere ask ed t o ans wer “yes,” “ma ybe,” or “no” t o the f ollowing ques tion: “ do y ou in tend t o participa te in Mea tless Monday?” To assess the r ate of PEBs perf ormed, a measur e w as adap ted fr om a pr evious s tudy (Brick, Sherman, & Kim, 2017). Using a fiv e-point Lik ert sc ale, with 1 = “ne ver” and 5 = “ always,” it ask ed how oft en participan ts perf ormed each of 12 PEBs in the pas t w eek, including “ carrying a reusable w ater bot tle,” “t aking public tr ansportation ins tead of t aking a c ar,” and “ eating or ganic food.” P articipants r eported PEBs perf ormed both a t baseline and a f ollow-up. The full lis t of the 12 PEBs assessed in both sur veys is pr ovided on the f ollowing pag e, in t able 2.

Table 2 List of 12 PEBs Assessed on E ach Sur vey

The f ood diaries (see Appendix C) assessed daily f ood/meat c onsumption per meal. T o assess this, participan ts w ere ask ed t o “brie fly describe wha t f ood the y a te f or each meal (e. g., chick en sandwich with side salad), and whe ther or not each meal c ontained mea t.” F or each meal (breakfast, lunch, dinner , and snack(s)), participan ts w ere giv en a small space f or these brie f qualitative descrip tions, and then r esponded either “y es” or “no” t o the f ollowing ques tion: “ did the meal c ontain mea t?” Mea t w as ag ain de fined as “ animal flesh tha t is c onsumed as f ood, including chick en, bee f, pork, fish, other sea food, e tc.,” with this de finition appearing on each individual f ood diar y.

Results

H1 Before t esting H1, the dif ferences in self -reported baseline mea t c onsumption be tween the experimental and c ontrol gr oup w ere analy zed. This analy sis utiliz ed the ne wly c alculated variable, “baseline mea t-containing meals per w eek” (described in the “Measur es” section), as well as r eported mea t-containing f or each of br eakfast, lunch, dinner , and snack(s) . While the experimental gr oup did r eport a sligh tly higher mean number of mea t-containing meals f or each meal than did the c ontrol gr oup, as w ell as a higher mean t otal f or the w eek, an independen t samples t -test r evealed tha t none of these baselines dif ferences w ere s tatistically signific ant. Results ar e displa yed belo w, in t able 3. Table 3 Reported F requency of Meat -Containing Meals During Baseline W eek

†p<.10, *p<.05, **p<.01, ***p<.001

Then, t o t est H1, independen t samples t -tests w ere run t o c ompare mea t c onsumption on Monday be tween tr eatment gr oups, both on an ag gregate and per -meal le vel. The da ta f or these t-tests w as t aken fr om the Monda y f ood diaries, which assessed mea t c onsumption per meal. Responses of “y es” t o the ques tion “ did the meal c ontain mea t?” w ere c oded as 1, wher eas responses of “no” w ere c oded as 0. Based on this c oding, a ne w binar y v ariable, “mea t on Monday,” w as c alculated t o indic ate whe ther the participan t had c onsumed mea t a t all on Monday (i.e., a 1 w as c oded f or a t leas t one of the f our meals). Ne w v ariables w ere also cr eated from these binar y f ood diar y r esponses t o c alculate the r atio of mea t-containing meals r eported for each of br eakfast, lunch, dinner , and snack(s), as w ell as f or Monda y o verall. It should be noted tha t the t otal r eported number of meals c onsumed dif fered among br eakfast, lunch, dinner, and snack(s), as some participan ts did not r eport c onsuming an y f ood f or cert ain meals (indicated b y qualit ative r esponses of “N/ A” on f ood diar y en tries). On Monda y, participan ts within the e xperimental gr oup r eported c onsuming mea t f or 30.9% of meals, wher eas participan ts within the c ontrol gr oup r eported c onsuming mea t f or 31.7% of meals. An independen t samples t -test r evealed tha t the dif ference w as not s tatistically signific ant (p = .903). Furthermor e, 32/53 (60.4%) of the e xperimental gr oup r eported c onsuming mea t a t least once on Monda y, wher eas 40/58 (69.0%) of the c ontrol gr oup r eported doing so. While the percentage of participan ts who r eported c onsuming mea t on Monda y w as descrip tively lo wer f or the e xperimental gr oup, a t -test ag ain r evealed tha t the dif ference w as not s tatistically signific ant (p = .350). Finally , when c omparing gr oups’ r eported mea t c onsumption f or individual meals, including br eakfast, lunch, dinner , and snack(s), independen t samples t -tests once mor e r evealed that an y dif ferences w ere not s tatistically signific ant. R esults ar e displa yed in t able 4 on the following pag e, with mean decimal v alues ha ving been c onverted t o per centages f or ease of interpretation.

Table 4 Comparison be tween T reatment Group s of R eported P ercentages of Meat -Containing Meals on Monday F ollowing In tervention

†p<.10, *p<.05, **p<.01, ***p<.001 Note. Denomina tors of meal c ounts (in par entheses) v ary bec ause some participan ts reported not c onsuming an y f ood f or cert ain meals.

An analy sis of the e xperimental gr oup in isola tion shed further ligh t on the r elative ineffectiveness of the Mea tless Monda y in tervention in motiv ating actual ab stention fr om Monday mea t c onsumption. Indeed, when the 53 participan ts of the e xperimental gr oup w ere asked if the y in tended t o participa te in Mea tless Monda y a fter r eceiving the in tervention, only

24 (45.3%) r esponded “y es,” while 20 (37.8%) r esponded “ma ybe,” and 9 (17%) r esponded “no. ” Then, among these thr ee gr oups, actual mea t c onsumption on Monda y v aried widely and did not always align with s tated in tentions, as sho wn belo w in t able 5. Table 5 Reported P ercentages of Meat -Containing Meals on Monday within Experimen tal Group, Categorized b y R esponses t o Ques tion: “Do Y ou In tend t o P articipate in Meatless Monday? ”

Note. Denomina tors of meal c ounts (in par entheses) v ary bec ause some participan ts reported not c onsuming an y f ood f or cert ain meals.

When c onsidering the r esults of t able 5, it should also be not ed tha t f or those who initially reported indecision r egarding participa tion in Mea tless Monda y (the “ma ybe” gr oup), v ery f ew

(4/20) actually did ab stain fr om mea t c onsumption on Monda y, r eflecting a possible disc onnect between in tent and actual beha vior. Ultimately, the da ta sho w tha t the in tervention w as ine ffective in motiv ating signific ant reductions in mea t c onsumption on Monda y. Ther efore, H1 (“individuals who r eceive an intervention enc ouraging participa tion in Mea tless Monda y will c onsume signific antly less mea t on Monda y, r elative t o no-in tervention c ontrols”) w as not support ed.

H2 To t est H2, the binar y r esponses t o the r epeated f ood diar y ques tion “ did the meal c ontain meat?” w ere ag ain analy zed, c onsidering binar y r esponses thr oughout the r est of the w eek. T en new v ariables, which c an be seen in t ables 6 and 7, w ere cr eated based on these r esponses. Fiv e of these v ariables w ere cr eated t o c alculate the r atio of mea t-containing meals r eported f or each of br eakfast, lunch, dinner , and snack(s) fr om T uesday thr ough Sunda y, as w ell as ag gregate totals f or tha t period. The other fiv e w ere then cr eated t o c alculate the same a forementioned ratios, but fr om Monday thr ough Sunda y. E ach of the v ariables (e. g., “mea t-containing meals f or breakfast thr oughout the w eek, incl. Monda y”) w as c omputed b y summing the 1’ s and 0’ s f or “yes” and “no” r esponses f or each meal f or each of the se ven da ys. This appr oach w as select ed due t o the f act tha t participan ts c ompleted dif ferent number s of f ood diaries (5-7), as w ell as the fact tha t f or cert ain meals, participan ts r eported c onsuming no f ood a t all. As f or the r esults, e vidence w as f ound f or the opposit e e ffect fr om wha t w as pr edicted in H2, namely, tha t individuals who r eceived the in tervention actually r eported c onsuming signific antly more mea t-containing meals the r est of the w eek, r elative t o c ontrols. This e ffect w as f ound b y conducting separ ate independen t samples t -tests f or the fir st fiv e ne wly cr eated v ariables (Tuesday thr ough Sunda y), c omparing the mean number of mea t-containing meals f or each of breakfast, lunch, dinner , and snack(s) be tween gr oups, as w ell as the ag gregate t otals. Within the e xperimental gr oup, participan ts r eported c onsuming mea t f or 39.0% of meals during the r est of the w eek, wher eas participan ts within the c ontrol gr oup r eported c onsuming meat f or only 31.6% of meals. An independen t samples t -test r evealed tha t the dif ference w as statistically signific ant ( p < .001). Indeed, the r eported per centages of mea t-containing meals

26 trended higher f or the e xperimental gr oup f or each of the f our meals, with br eakfast and dinner being signific antly higher ( p = .010 and .026, r espectively). R esults ar e displa yed belo w, in t able 6. Table 6 Comparison be tween T reatment Group s of R eported P ercentages of Meat -Containing Meals from T uesday through Sunday F ollowing In tervention

†p<.10, *p<.05, **p<.01, ***p<.001 Note. Denomina tors of meal c ounts (in par entheses) v ary bec ause some participan ts reported not c onsuming an y f ood f or cert ain meals.

Similar r esults w ere also f ound when c onsidering the w eek in t otality (Monda y thr ough Sunday) and c onducting independen t samples t -tests f or the other fiv e ne wly cr eated v ariables, as sho wn on the f ollowing pag e in t able 7. These r esults thus sho w an associa tion be tween exposure t o the in tervention and incr eased mea t c onsumption thr oughout the w eek.

Table 7 Comparison be tween T reatment Group s of R eported P ercentages of Meat -Containing Meals from Monday through Sunday F ollowing In tervention

†p<.10, *p<.05, **p<.01, ***p<.001 Note. Denomina tors of meal c ounts (in par entheses) v ary bec ause some participan ts reported not c onsuming an y f ood f or cert ain meals.

Furthermore, when c omparing the mean number of da ys thr oughout the w eek on which participants r eported c onsuming mea t a t leas t once, the mean number w as almos t one full da y higher f or the e xperimental gr oup than f or the c ontrol gr oup. This e ffect held both when including and e xcluding Monda y fr om the c alculation. These r esults w ere g enerated b y cr eating two ne w v ariables, “t otal mea t-containing da ys, incl. Monda y” and “t otal mea t-containing da ys, excl. Monda y.” These v ariables w ere c alculated b y summing the number of da ys (up t o 7 or 6,

28 respectively) f or which a c oded v ariable r esponse of 1 (indic ating mea t c onsumption) w as reported f or a t leas t one meal. When e xcluding Monda y (i.e., assessing mea t c onsumption T uesday thr ough Sunda y), the mean number of mea t-consuming da ys r eported w as 3.74 f or the c ontrol gr oup and 4.71 f or the experimental gr oup, and when including Monda y, the mean number r eported w as 4.43 f or control and 5.32 f or e xperimental. Independen t samples t -tests r evealed tha t these dif ferences between tr eatment gr oups in mean number of mea t-consuming da ys w ere indeed signific ant, both when e xcluding and including Monda y ( p = .003 and .018, r espectively). These r esults ar e displayed belo w, in t able 8. Table 8 Comparison be tween T reatment Group s of Mean Number of Days on which Meat was Consumed During W eek F ollowing In tervention

†p<.10, *p<.05, **p<.01, ***p<.001

Therefore, bec ause the e xperimental gr oup c onsistently r eported higher le vels of mea t consumption thr oughout the w eek, H2 (“individuals who r eceive an in tervention enc ouraging participation in Mea tless Monda y will c onsume signific antly less mea t the r est of the w eek, relative t o c ontrols”) w as also not support ed b y the da ta.

H3 Before t esting H3, a r eliability analy sis w as c onducted r egarding 11 of the PEBs assessed on the baseline sur vey. The 12th PEB , which assessed the fr equency with which participan ts consumed “ animal pr oducts such as milk, cheese, eg gs, or y ogurt,” w as e xcluded fr om the reliability analy sis due t o its r esemblance t o prior ques tions assessing r ates of mea t consumption. The analy sis demons trated tha t such f actors did not function w ell c ollectively as a scale (Cr onbach’s α = .607). The baseline PEBs w ere then analy zed individually , with tw o PEBs (carrying a r eusable w ater bot tle and turning of f ligh ts when e xiting a r oom) being elimina ted due t o e xcessive sk ewness (|sk ewness| = 2.434 and 1.590, r espectively). Ther efore, r eported frequencies of nine PEBs w ere c onsidered f or the purposes of t esting H3, which appear in t able 9 below. First analy zed w ere the dif ferences in self -reported baseline PEBs be tween the e xperimental and c ontrol gr oups. Independen t samples t -tests c omparing the mean r eported fr equencies of each of the nine PEBs (measur ed on 5-poin t Lik ert sc ales fr om 1 - “ne ver” t o 5 - “ always”) revealed no signific ant baseline dif ferences be tween the tw o tr eatment gr oups. R esults ar e displayed on the f ollowing pag e, in t able 9.

Table 9 Comparison be tween T reatment Group s of Mean R eported F requency of PEBs P erformed During Baseline W eek

†p<.10, *p<.05, **p<.01, ***p<.001

After c onducting this baseline analy sis, another se t of independen t samples t -tests w as performed t o de termine if signific ant dif ferences e xisted in the mean r eported fr equencies of each PEB be tween the tr eatment gr oups during the w eek of the Mea tless Monda y in tervention (based on the f ollow-up sur vey). The mean r eported fr equency only dif fered signific antly f or 1 out of 9 f ollow-up PEBs, prin ting on both sides of a shee t of paper . In this c ase, the mean reported fr equency f or the c ontrol gr oup w as higher than tha t of the e xperimental gr oup (4.05 vs 3.44, p = .033). R esults ar e displa yed on the f ollowing pag e, in t able 10.

Table 10

Comparison be tween T reatment Group s of Mean R eported F requency of PEBs P erformed During W eek F ollowing In tervention

†p<.10, *p<.05, **p<.01, ***p<.001

Therefore, H3 (“individuals who r eceive an in tervention enc ouraging participa tion in Meatless Monda y will perf orm signific antly mor e PEBs thr oughout the w eek, r elative t o no-intervention c ontrols”) w as also not support ed b y the da ta.

Exploratory Analysis- Comparison of PEBs Performed between those who did and did not Engage in Meatless Monday

Because the in tervention w as f ound t o be lar gely ine ffective in motiv ating s tudy participan ts to actually ab stain fr om mea t c onsumption on Monda y, a further e xploratory analy sis w as conducted t o de termine whe ther beha vioral spillo ver ma y ha ve occurr ed be tween those who actually eng aged in Mea tless Monda y and the r est of the sample, as opposed t o simply comparing the e xperimental gr oup t o the c ontrol gr oup. Actual eng agement in Mea tless Monda y was de fined f or these purposes as those participan ts within the e xperimental gr oup who responded either “y es” or “ma ybe” when ask ed if the y in tended t o participa te in Mea tless Monday, and who then did not c onsume an y mea t on Monda y. B y this de finition, ther e w ere 19 participants who actually eng aged in Mea tless Monda y, out of 53 member s of the e xperimental group and 111 member s of the en tire sample. A ne w binar y gr ouping v ariable, “Mea tless Monday eng agement” w as c oded based upon these f actors. In r egards t o PEBs, 8 ag ain analy zed w ere the dif ferences in self -reported baseline PEBs between the tw o a forementioned gr oups, namely , be tween those who eng aged in Mea tless Monday and those who did not. Independen t samples t -tests r evealed tha t the only s tatistically significant dif ference w as once mor e in r elation t o PEB #2 (prin ting on both sides of a shee t of paper), which the non-Mea tless Monda y eng agement gr oup r eported perf orming signific antly more oft en than did the eng agement gr oup ( x ̄ = 3.77 v s 3.11, p = .044). R esults ar e displa yed on the f ollowing pag e, in t able 11.

8 Note that potential behavioral spillover in the form of differences in meat consumption during the rest of the intervention week (Tuesday-Sunday) was not tested for, given that statistically significant differences in baseline meat consumption were reported between these two groups.

Table 11 Comparison of Mean R eported F requency of PEBs P erformed During Baseline W eek, Grouped b y those who E ngaged in Meatless Monday and those who did not

†p<.10, *p<.05, **p<.01, ***p<.001

However, when c omparing f ollow-up PEBs, the Mea tless Monda y eng agement gr oup reported perf orming tw o PEBs signific antly mor e oft en than did the non-eng agement gr oup, namely PEB #1 (“w alk, bicy cle, or t ake public tr ansportation ins tead of t aking a c ar”) and PEB #4 (“use r eusable bags when shopping ”). R esults ar e sho wn on the f ollowing pag e, in t able 12.

Table 12 Comparison of Mean R eported F requency of PEBs P erformed During W eek F ollowing Intervention, Grouped b y those who E ngaged in Meatless Monday and those who did not

†p<.10, *p<.05, **p<.01, ***p<.001

Exploratory Analysis- Changes in Psychological Correlates from Baseline to Follow-Up among Experimental Group

Of further in terest t o the r esearch t eam w ere chang es in p sychological c orrelates among the participants within the e xperimental gr oup fr om baseline t o f ollow-up, which c ould shed ligh t on wh y the in tervention w as r elatively ine ffective in pr oducing the h ypothesized r esults. Assessed a t both baseline and f ollow-up w ere en vironmental iden tity, per ceptions r egarding abstention fr om mea t c onsumption (including beha vioral dif ficulty), and a wareness of the negative en vironmental impacts of mea t c onsumption, each of which functioned as a sc ale (see Appendix D f or measur es). P aired samples t -tests w ere c onducted t o assess the e xtent tha t these f actors chang ed fr om baseline t o f ollow-up, with a wareness of the neg ative environmental impacts of mea t c onsumption incr easing signific antly9 , as sho wn in t able 13. Table 13 Analysis of Changes in Ps ychological Correlat e Sc ales from Baseline t o F ollow-Up among Experimental Group

†p<.10, *p<.05, **p<.01, ***p<.001 Note. E ach sc ale w as assessed via se ven-point Lik ert sc ales, with a positiv e numeric al chang e representing a positiv e chang e (e. g., incr eased positiv e per ceptions r egarding ab stention

from mea t c onsumption one da y per w eek), and vice v ersa.

9 Paired samples t-tests revealed no significant changes in scales from baseline to follow-up for the control group.

Additional pair ed samples t -tests w ere c onducted t o assess chang es f or each individual factor of the per ceptions r egarding ab stention fr om mea t c onsumption sc ale. Signific ant changes w ere f ound in r egards t o per ceptions r egarding ho w eas y it w ould be t o ab stain fr om meat c onsumption one da y per w eek, with a decr ease of beha vioral ease/incr ease in per ceived behavioral dif ficulty a t f ollow-up, and ho w much of a positiv e en vironmental impact such behavior w ould ha ve, with an incr ease in per ceived positiv e impact 1 0, as sho wn in t able 14. Table 14 Analysis of Changes in Specific Measures from P erceptual Sc ale from Baseline t o F ollow-Up among Experimen tal Group

†p<.10, *p<.05, **p<.01, ***p<.001

Note. E ach sc ale measur e w as assessed on a se ven-point Lik ert sc ale, with a positiv e numerical chang e r epresenting a positiv e chang e (e. g., an incr eased per ception of the positive impact the beha vior w ould ha ve on the en vironment), and vice v ersa.

10 Paired samples t-tests revealed no significant changes from baseline to follow-up in any individual perpetual factor for the control group.

Discussion

In all, each of the thr ee h ypotheses w ere r ejected. R egarding H1, participan ts who r eceived the in tervention enc ouraging participa tion in Mea tless Monda y did not c onsume signific antly less mea t on Monda y, r elative t o no-in tervention c ontrols. In r egards t o the ine ffectiveness of the in tervention in pr omoting eng agement in Mea tless Monda y, one possible e xplanation r elates to the t emporal g ap be tween participan ts’ e xposure t o the fly er and t o the actual decision poin t of whe ther or not t o c onsume mea t on Monda y. Bec ause participan ts w ere able t o c omplete the baseline sur vey as early as Thur sday a t 8 A .M. on a giv en w eek, some participan ts ma y ha ve had a g ap of almos t 100 hour s be tween the time tha t the y r ead the fly er and the time tha t the y fir st consumed f ood on Monda y. This pot ential t emporal g ap does not align w ell with r esearch findings tha t sug gest tha t jus t-in-time in terventions ma y be mor e e ffective in f acilitating positiv e behavior chang e, b y pr oviding beha vioral support a t the e xact decision poin t, when it is mos t needed (Nahum-Shani e t al., 2014; Thomas & Bond, 2015). Indeed, the pot ential t emporal g ap in this s tudy ma y ha ve made the Mea tless Monda y messaging mor e p sychologically dis tant, and thus c ontributed t o decr eased in tervention e ffectiveness. It should be not ed tha t participan ts were r eminded in their Sunda y nigh t ins tructional email about the pot ential t o eng age in Meatless Monda y the f ollowing da y, but this r eminder w as only cur sory in na ture and did not contain the dif ferent p sychological mechanisms such as en vironmental iden tity and social norms that w ere inc orporated in the fly er. Furthermor e, participan ts ma y ha ve simply neglect ed t o open the Sunda y nigh t email, and thus f orgotten about Mea tless Monda y be fore c onsuming meat on tha t da y. Another possible e xplanation r elates t o the lack of a manipula tion check v erifying tha t participants actually r ead the electr onic fly er. Indeed, especially in c onsideration of the r elatively long leng th of the fly er (see Appendix B), it is possible tha t participan ts simply scr olled and clicked thr ough the electr onic fly er without fully under standing and c onsidering its messaging. This w as a signific ant short coming in the sur vey me thodology. Ho wever, bec ause e xploratory analyses r evealed tha t both a wareness of the neg ative en vironmental impacts of mea t consumption and per ceptions of the pot ential en vironmental impact of ab stention fr om mea t consumption incr eased signific antly a t f ollow-up, this w ould not seem t o en tirely e xplain the

39 ineffectiveness of the in tervention, giv en tha t the in tervention did indeed ha ve a signific ant effect on these f actors. However, e xploratory analy ses r evealed a pot ential alt ernate e xplanation, namely , tha t a t baseline participan ts ma y ha ve under estimated the dif ficulty of ab stention fr om mea t consumption one da y per w eek, as it w as f ound tha t per ceived beha vioral dif ficulty incr eased significantly a t f ollow-up. Indeed, when c onfronted with the actual decision of whe ther or not t o consume mea t on Monda y, participan ts ma y ha ve been unable t o br eak fr om pr eviously-formed habits of mea t c onsumption, or ma y ha ve r ealized tha t the y did not ha ve adequa te mea t substitutes a vailable, among other man y other possible barrier s (St oll-Kleemann & Schmidt, 2017). These e ffects then c ould ha ve led t o lo wer r ates of eng agement in Mea tless Monda y. Additionally, it is import ant t o c onsider the f ormat of in tervention used. A gr owing body of literature has demons trated tha t in formational in terventions c an be r elatively ine ffective when compared t o other f orms of beha vioral in terventions (e. g., St öckli, Niklaus, & Dorn, 2018), and indeed, the in tervention used in the s tudy w as lar gely in formational. Ther efore, it is quit e possible tha t a gr eater per centage of participan ts w ould ha ve eng aged in Mea tless Monda y and reduced their cumula tive mea t c onsumption had another f orm of in tervention been utiliz ed. This point is signific ant bec ause much of the messaging used t o pr omote the Mea tless Monda y campaign in r eality is also in formational, and thus ma y not be ma ximally e ffective in pr omoting engagement in the mo vement. The r esults in this s tudy sug gest tha t c ampaigners w ould be well-suited t o c onsider other f orms of beha vioral in terventions when pr omoting Mea tless Monday, in addition t o in formational messaging. Relatedly, the in tervention in this s tudy f ocused on en vironmental-related messaging , as opposed t o health-r elated messaging , which ma y ha ve limit ed its e ffectiveness. Indeed, r esearch has sho wn tha t health-r elated messaging is oft en mor e e ffective than en vironmental-related messaging in pr omoting positiv e beha vior chang e (e. g, La tvala e t al., 2012; Ne ff, E dwards, & Palmer, 2018). These prior findings ar e particularly g ermane t o this s tudy bec ause e xploratory analyses f ound tha t the e xperimental gr oup’s a wareness of the neg ative impacts of mea t production incr eased signific antly, as did its per ception of the positiv e en vironmental impacts of abstaining fr om mea t c onsumption, but despit e this, its actual mea t c onsumption did not decrease signific antly. Ther efore, it is e vident tha t en vironmental a wareness and

40 environmental-related messaging w as lar gely ine ffective in motiv ating positiv e beha vior chang e among the sample, and as such, it is possible tha t health-r elated messaging ma y ha ve been mor e effective. Finally, it should be not ed tha t the initial r andomization of participan ts in to e xperimental and control gr oups partially f ailed. A t baseline, the e xperimental gr oup r eported c onsuming o ver one additional mea t-containing meal of the c ourse of a w eek when c ompared t o the c ontrol gr oup, though this e ffect w as not s tatistically signific ant. Ho wever, dis tribution of self -reported die tary patterns did dif fer signific antly be tween tr eatment gr oups, with the e xperimental gr oup composed of a signific antly higher per centage of omniv ores, as opposed t o part -time and pesco-vegetarians. Ther efore, it is possible tha t higher r ates of mea t c onsumption f or the experimental gr oup a t baseline limit ed the ability f or signific ant decr eases in mea t c onsumption to be ob served on Monda y, r elative t o the c ontrol gr oup. Many of these same f actors tha t lik ely impact ed H1 also lik ely impact ed the r esults of H2 and H3. F or H2, the e xperimental gr oup r eported c onsuming a signific antly higher per centage of meat-containing meals thr oughout the in tervention w eek, in addition t o r eporting a signific antly higher mean number of da ys with an y mea t c onsumption. Ag ain, these findings ma y pot entially be a ttributed, a t leas t in part, t o the f ailed r andomization a t baseline be tween the tw o gr oups. Ultimately, ho wever, the r ejection of the H2 h ypothesis is lik ely closely r elated t o the ineffectiveness of the Mea tless Monda y in tervention, as it w ould not be e xpected tha t participants w ould signific antly r educe mea t c onsumption on T uesday thr ough Sunda y if the y did not fir st signific antly r educe mea t c onsumption on Monda y. Similarly, f or H3 and pr o-environmental beha vioral spillo ver, it w as not e xpected tha t positiv e spillover w ould occur without fir st widespr ead adop tion of the t arget beha vior, namely , abstention fr om mea t c onsumption on Monda y. Ther efore, bec ause adop tion of the t arget behavior w as limit ed, the f act tha t a signific antly higher r ate of PEBs among the e xperimental group w as not ob served in c omparison t o c ontrols limits our ability t o dr aw s trong c onclusions about pr o-environmental spillo ver beha vior. Despit e this, the finding tha t tw o of the nine PEBs were signific antly higher among those who actually eng aged in Mea tless Monda y c ould potentially r eflect this kind of spillo ver (though it is also possible tha t this finding w as simply due to chance). R egardless, it is cert ainly c onceivable tha t a lar ger and mor e r epresentative sample

(discussed belo w), c oupled with higher r ates of eng agement in the t arget beha vior, w ould ha ve yielded much s tronger e vidence r elated t o pr o-environmental spillo ver beha vior. It should be not ed also tha t e vidence w as not f ound f or the neg ative spillo ver pa thway proposed in V erfeuth e t al., 2019, as a pot ential e xplanation f or wh y the in tervention w as ineffective. In the s tudy, it w as pr oposed tha t c onflicting iden tities w ould lead t o the c ontent of a given in tervention t o bec ome less cen tral t o individuals, leading t o w eakening of en vironmental identity, r eactive beha vior, and neg ative spillo ver. Ho wever, e xploratory analy ses r evealed tha t environmental iden tity (see Appendix D f or measur es) did not chang e signific antly fr om baseline to f ollow-up among the e xperimental gr oup. Thus, without signific ant w eakening of environmental iden tity, the c onflicting iden tities pa thway w ould not be e xpected t o ha ve occurred. Indeed, it ma y be mor e lik ely tha t c ompartmentalization1 1 e ffects occurr ed t o a t leas t a limited e xtent, r eflective of a g eneral lack of pr o-environmental spillo ver beha vior, though this cannot be wholly v erified b y the sur vey measur es utiliz ed in this s tudy.

Limitations and F uture Directions

There w ere multiple signific ant limit ations of this s tudy r elated t o sample. Demogr aphics of the participan ts w ere highly homog enous in man y r espects, including the f ollowing f actors: (1) age- 90.1% be tween 18 and 22 y ears old; (2) g ender- 68.5% f emale; (3) r ace- 93.7% whit e; (4) political a ffiliation- 66.7% liber al; and (5) par ental educ ation- 77.5% in situa tions wher e a t leas t one par ent had c ompleted a 4- year c ollege degr ee. The sample w as also r elatively small, with fewer than 60 participan ts assigned t o each tr eatment gr oup. The sample c annot be c onsidered representative of the popula tion a t lar ge; and futur e r esearch is ther efore needed t o de termine how e ffects migh t chang e with a mor e r epresentative sample. Additionally, bec ause the majority of s tudents within the sample w ere pur suing major s within SENR, these participan ts lik ely had f ar mor e kno wledge of and in terest in en vironmental issues than the g eneral popula tion. Indeed, participan ts sc ored highly on baselines sc ales1 2 f or

11 Compartmentalization within the context of the Verfeuth et al. study describes a separation of the behavior from environmental identity and resultant lack of spillover, as outlined in the introduction. 12 These were measured on seven-point Likert scales. Scale measures and reliability analyses for each of the three scales referenced in this paragraph are described in the appendix.

42 both en vironmental iden tity ( x ̄ = 5.9, σ = .95) and a wareness of the en vironmental impacts of meat pr oduction ( x ̄ = 5.8, σ = 1.25), making it so tha t ther e w as lik ely limit ed ability t o incr ease these f actors as a r esult of the Mea tless Monda y in tervention. Ho wever, r egarding environmental iden tity specific ally, giv en the w ell-documented desir e f or humans t o act consistently with their iden tities (e. g, F estinger, 1957; Thøg ersen, 2004), it is some what unexpected tha t Mea tless Monda y eng agement r ates w ere not higher , giv en the pr evalence of self-described en vironmentalists among the sample. Similarly, participan ts r eported r elatively lo w le vels of baseline per ceived beha vioral dif ficulty (x̄ = 5.2, σ = 1.19) when c onsidering the possibility of ab staining fr om mea t one da y per w eek, again pot entially limiting the ability t o f acilitate a meaningful chang e as a r esult of the intervention. Bec ause ther e ar e numer ous mea tless op tions of fered thr ough the univ ersity’s dining ser vices, it is cert ainly possible tha t this baseline per ceived beha vioral dif ficulty ma y ha ve been lo wer f or the sample than it w ould ha ve been f or the g eneral popula tion, giv en incr eased access t o such mea tless op tions and decr eased need f or actual mea tless c ooking skills. Therefore, futur e r esearch is needed t o ascert ain ho w e ffective such an in tervention migh t be in motivating r educed mea t c onsumption and pr o-environmental spillo ver beha vior when the sample is mor e r epresentative of the popula tion in r egards t o en vironmental issues and perceptions r egarding mea t c onsumption, thus incr easing the pot ential t o motiv ate chang e in these r espects. Furthermore, futur e r esearch is w arranted t o iden tify the specific f actors tha t ma y ha ve contributed t o the r elative ine ffectiveness of the Mea tless Monda y in tervention. Bec ause multiple v ariables w ere assessed in the baseline and f ollow-up sur veys tha t migh t r eveal information about such f actors (e. g., en vironmental iden tity, per ceived beha vioral dif ficulty, awareness of the neg ative en vironmental impacts of mea t pr oduction), ther e is a signific ant opportunity f or further da ta analy sis a t a futur e time, with only cur sory e xploratory analy ses having been perf ormed in this s tudy. Further da ta analy sis is also w arranted t o in vestigate the potential r ole of c ognitive accessibility in media ting beha vioral spillo ver among PEBs (see Appendix D , F). Additionally , ther e is jus tification f or perf orming a similar s tudy with a manipulation check t o ensur e tha t the in tervention (in this c ase, the fly er) w as actually r ead and fully under stood, giv en the not able lack of such a check in this s tudy.

Other futur e dir ections include the br oader needs f or additional s tudy of mea t c onsumption reduction in terventions g enerally and the f actors tha t ma y mak e them mor e or less e ffective. One possible ar ea of e xploration r elates t o the specific f ood c onsumed when people r educe their meat c onsumption without bec oming fully v egetarian or v egan, about which lit tle is curr ently known (Ne ff e t al., 2018). A similar e xperimental design t o tha t of this s tudy, utilizing f ood diaries, c ould addr ess this r esearch g ap, if the underlying f actors tha t made the in tervention ineffective w ere addr essed. Also , futur e r esearch in vestigating the c onditions under which pro-environmental spillo ver beha vior ma y occur , especially when adop tion of the t arget beha vior is mor e widespr ead, is jus tified. This ar ea in particular is import ant so tha t policymak ers ma y design mor e e ffective beha vioral in terventions tha t minimiz e neg ative spillo ver and ma ximize positive spillo ver. Finally, additional e xperimental r esearch in to the Mea tless Monda y c ampaign fr om a br oader perspective is necessar y, both t o addr ess the limit ations of the curr ent s tudy, and t o e xpand upon them. Specific ally, bec ause the da ta r evealed tha t mea t c onsumption did not signific antly decrease despit e incr eased a wareness of the neg ative en vironmental impacts of mea t production, e xperimental r esearch tha t c ompares the e ffectiveness of en vironmental-related messaging t o health-r elated messaging f or the purposes of pr omoting Mea tless Monda y is warranted. Indeed, bec ause the c ampaign pr omotes ab stention fr om mea t c onsumption on Monday f or both en vironmental and health r easons, if indeed health-r elated messaging w ere found t o be mor e e ffective in motiv ating r educed mea t c onsumption beha vior, mark eters w ould potentially be able t o incr ease the e ffectiveness of Mea tless Monda y while s till aligning with the campaign’s s tated in tent.

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Appendix

A. Sample Digit al R ecruitment Flyer

B. Meatless Monday Flyer

C. Sample Digit al F ood Diar y

C. Sample Digit al F ood Diar y (c ont)

D. Descrip tion of Additional Sur vey Measures

To assess a wareness of the en vironmental impacts of mea t pr oduction, tw o measur es w ere modified fr om pr evious s tudies (P ohjolainen e t al., 2016; Mullee e t al., 2017). The r esultant fiv e questions ask ed, f or e xample, the e xtent t o which participan ts agr eed tha t mea t pr oduction is bad f or the en vironment, and tha t mea t pr oduction is signific antly mor e land-in tensive than plant pr oduction, among other crit eria. P articipants r esponded via se ven-point Lik ert sc ales (1 = “strongly disagr ee,” 7 = “ strongly agr ee”). A r eliability analy sis demons trated tha t these f actors functioned w ell as a sc ale (Cr onbach’s α = .902). Thus, a ne w sc ale v ariable, “ awareness of the negative en vironmental impacts of mea t pr oduction,” w as cr eated, which a veraged participan ts’ numerical r esponses t o these fiv e ques tions. To assess en vironmental iden tity, thr ee ques tions w ere r eproduced fr om a pr evious s tudy (van der W erff e t al., 2013). Using a se ven-point Lik ert sc ale (1 = “ strongly disagr ee,” 7 = “ strongly agree”), the it ems assessed the e xtent t o which participan ts agr eed with the f ollowing statements: “ acting en vironmentally-friendly is an import ant part of who I am, ” “I am the type of person who acts en vironmentally friendly ,” and “I see m yself as an en vironmentally-friendly person.” A r eliability analy sis demons trated tha t these f actors functioned w ell as a sc ale (Cronbach’s α = .892). Thus, a ne w sc ale v ariable, “ environmental iden tity,” w as cr eated, which averaged participan ts’ numeric al r esponses t o these thr ee ques tions. To assess per ceptions r egarding ab stention fr om mea t c onsumption one da y per w eek, including per ceived beha vioral dif ficulty, fiv e ques tions w ere adap ted fr om a pr evious s tudy (Truelove & Gillis, 2018). These it ems ask ed participan ts t o indic ate, if the y w ere t o ab stain fr om eating mea t one da y per w eek, “ho w dif ficult it w ould be, ” “ho w inc onvenient it w ould be, ” “ho w the f ood w ould t aste on tha t da y,” “ho w enc ouraging f amily and friends w ould be of y our behavior,” and “ho w much of a positiv e impact it w ould ha ve on the en vironmental o verall.” Participants r esponded via se ven-point Lik ert sc ales (e. g., 1 = “ extremely dif ficult,” 7 = “ extremely easy”). A r eliability analy sis demons trated tha t these f actors functioned w ell as a sc ale (Cronbach’s α = .785). Thus, a ne w sc ale v ariable, “per ceptions r egarding ab stention fr om mea t consumption one da y per w eek,” w as cr eated, which a veraged participan ts’ numeric al r esponses to these fiv e ques tions.

D. Descrip tion of Additional Sur vey Measures (c ont.)

To assess c ognitive accessibility of en vironmental f actors r elated t o die t (see Appendix F), tw o measures w ere modified fr om a pr evious s tudy (Sin tov e t al., 2017). The r esultant six ques tions assessed the e xtent t o which participan ts c onsidered the land, w ater, and ener gy used in production when choosing wha t f ood t o buy and ea t. F or e xample, participan ts w ere ask ed the extent t o which the y agr eed or disagr eed with the f ollowing s tatement: “I c onsider the land tha t was used in pr oduction when I choose wha t kind of f ood t o ea t.” P articipants r esponded via seven-point Lik ert sc ales (1 = “ strongly disagr ee, 7 = “ strongly agr ee”). A r eliability analy sis demonstrated tha t these f actors functioned w ell as a sc ale (Cr onbach’s α = .926). Thus, a ne w scale v ariable, “ cognitive accessibility ,” w as cr eated, which a veraged participan ts’ numeric al responses t o these six ques tions.

E. Discussion of Social Norms

The pot ential in fluence of social norms w as le veraged in the fly er as a pot ential means of increasing eng agement in Mea tless Monda y, in t andem with en vironmental iden tity and other factors. Social norms c an be de fined as s tandards and rules tha t ar e c ollectively under stood b y members of a gr oup, and tha t guide and/ or c onstrain social beha vior without the in fluence of laws (Cialdini & T rost, 1998). Social norms ha ve been link ed t o beha vioral spillo ver (St einhorst, Klöckner, & Ma tthies, 2015). F or e xample, r esearch has demons trated tha t people ar e mor e likely t o eng age in ener gy-saving beha vior when in terventions ar e fr amed as norma tive appeals, rather than as appeals t o bene fit the en vironment or sa ve mone y (Nolan, Schultz, & Cialdini, 2008). Indeed, when in trinsic motiv ation f or perf orming a PEB (i.e. t o bene fit the en vironment) is insufficient, social norms ma y pr ovide the necessar y e xternal motiv ation t o in fluence beha vior and g enerate associa ted spillo ver e ffects (Nash e t al., 2017). Social norms w ere inc orporated in the fly er b y highligh ting tha t “millions of people in o ver 40 countries” and an “ ever-growing number of Ohio St ate s tudents” w ere participa ting in Mea tless Monday, thus r eflecting tha t eng agement with the c ampaign w as a socially accep table and relatively c ommon pr actice among participan ts’ peer s. Ho wever, bec ause the fly er w as lar gely ineffective and bec ause the only measur e r elated t o social norms (the e xtent t o which f amily and friends w ould be enc ouraging of mea t c onsumption r eduction) did not sho w signific ant chang e from baseline t o f ollow-up, it is dif ficult t o e valuate the e ffect tha t social norms had on the t arget behavior, if an y.

F. Discussion of Cognitive Ac cessibility

One r elatively no vel v ariable tha t has been pr oposed in r elation t o the en vironmental identity pa thway is tha t of c ognitive accessibility . The t erm “ cognitive accessibility ” r efers t o the frequency b y which people think about cert ain ideas. It is r elated t o the a vailability heuris tic and self-perception theor y, the w ell-documented t endencies f or people t o o verweight in formation that c an be men tally r ecalled immedia tely (T versky & K ahneman, 1973; Sch warz e t al., 1991; Pachur, Hertwig , & St einmann, 2012), and t o r efer back t o pr evious beha viors as r epresentative of their self -concept (Bem, 1972), r espectively, when making decisions. In an en vironmental context, c ognitive accessibility r efers t o individuals’ t endency t o fir st think about prior PEBs when making decisions r egarding futur e PEBs, and then t o o verweight pas t PEBs tha t ar e easies t t o mentally r ecall (i.e. those tha t ha ve occurr ed mor e r ecently or mor e fr equently). As pr eviously referenced, in a r ecent s tudy, c ognitive accessibility w as h ypothesized as a pot ential media tor between c omposting and spillo ver t o other household w aste pr evention beha viors, and indeed, evidence w as f ound t o support this h ypothesis in r egards t o cert ain w aste pr evention beha viors (Sintov, Geislar , & Whit e, 2017). However, it does not appear tha t further s tudies ha ve in vestigated the pot ential r ole of cognitive accessibility as media ting spillo ver among PEBs, lea ving a signific ant opportunity f or further r esearch. In r egards t o mea t c onsumption, insof ar as daily die tary choices of fer r epeated opportunities t o eng age in PEBs, c ognitive accessibility ma y indeed media te spillo ver t o other PEBs, especially those in the same die tary beha vioral domain. Ther efore, while the pot ential r ole of c ognitive accessibility w as not dir ectly analy zed in this s tudy, specific measur es r elated t o cognitive accessibility w ere indeed included (see Appendix D), so as t o in vite further analy sis in the futur e.