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Sustainability: Science, Practice and Policy

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Spillover effects of sustainable consumption:combining identity process theory and theories ofpractice

Marcia Frezza, Lorraine Whitmarsh, Martina Schäfer & Ulf Schrader

To cite this article: Marcia Frezza, Lorraine Whitmarsh, Martina Schäfer & Ulf Schrader(2019) Spillover effects of sustainable consumption: combining identity process theoryand theories of practice, Sustainability: Science, Practice and Policy, 15:1, 15-30, DOI:10.1080/15487733.2019.1567215

To link to this article: https://doi.org/10.1080/15487733.2019.1567215

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Published online: 19 Feb 2019.

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RESEARCH ARTICLE

Spillover effects of sustainable consumption: combining identity processtheory and theories of practice

Marcia Frezzaa,b , Lorraine Whitmarshc , Martina Sch€afera and Ulf Schraderd

aCenter for Technology and Society, Technische Universit€at Berlin, Berlin, Germany; bLaboratory of Human-EnvironmentalRelations Studies, Postgraduate Program in Psychology, Universidade de Fortaleza, Fortaleza-CE, Brazil; cSchool of Psychology,Cardiff University, Cardiff, UK; dDivision of Economic Education and Sustainable Consumption, Institute of Vocational Educationand Work Studies, Technische Universit€at Berlin, Berlin, Germany

ABSTRACTWork organizations that implement sustainability strategies can create supportive environ-ments for the performance of sustainable routines. For instance, employers have the cap-acity to influence sustainable lifestyles of their employees by increasing spillover effectsfrom workplaces to home settings. These circumstances provide a potential pathway tochange routinized activities in different domains. We critically review sociological and psy-chological literature on practices of environmental relevance to better understand thesespillover effects. These disciplines have contributions to make but are on their own insuffi-cient to determine trajectories toward more sustainable (consumption) routines. This analysisthus considers both structural and individual dimensions of sustainable lifestyles. To advanceanalyses of spillover of routinized activities, we present a framework that combines theoriesof practice concepts (meanings, competencies, and material aspects) and principles of iden-tity process theory (continuity, distinctiveness, self-esteem, and self-efficacy). Our frameworkaims to identify and assess spillover effects from the workplace to domestic settings. Weshow that work organizations can systematically provide the elements necessary for the per-formance of sustainable practices. The framework underpins methodological instruments toexplain spillover effects (of sustainable consumption), equally encompassing individual andstructural aspects.

ARTICLE HISTORYReceived 2 January 2018Accepted 16 December 2018

KEYWORDSCross-situational spillover;sustainable consumption;identity process theory;theories of practice; workand domestic routines

Introduction

Numerous governmental and institutional reports(UNDP 2016; WCED 1987) and academic publications(e.g. Nash et al. 2017; Jaeger-Erben, R€uckert-John andSch€afer 2015; Whitmarsh 2016; Sch€afer and Jaeger-Erben2012; Schrader and Thøgersen 2011) released inrecent years have sought to encourage sustainablelifestyles. Achieving these changes demands profoundand expansive measures (Nash et al. 2017; Thøgersenand Crompton 2009). Interventions that target iso-lated behaviors or technologies, for instance, areunlikely to be sufficient to provide alternative life-styles toward sustainable societies. For instance,Thøgersen and Crompton (2009, p. 142) observe thatmeasures will need to entail ‘far-reaching changes inindividual behavior, fundamental changes in businesspractice, and the implementation of ambitious newpolicies and regulations to drive’ interventions.Several researchers assert that spillover effects, suchas behavioral spillover, offer potential pathways tofoster more sustainable lifestyles (Nash et al. 2017;

Muster 2011; Thøgersen and Crompton 2009). If theperformance of one behavior affects the probabilityof practitioners to engage (positive spillover) or dis-engage (negative spillover) in a second behavior(Truelove et al. 2014), interventions to promote sus-tainability could take advantage of such mechanismsto increase the probability of promoting non-targetedsustainable behavior (Nilsson, Bergquist, and Schultz2016). Another form of spillover occurs between con-texts (cross-situational spillover) when the perform-ance of a behavior in one context affects theprobability of performing this behavior in a secondcontext. Given the need to accelerate societal changeto address sustainability challenges like climatechange, policies and other interventions that favorspillover effects may offer ways to catalyze broad life-style changes more effectively and significantly.

Household consumption has a significant – andgrowing – impact on the environment, as well as onpeople’s living conditions (Eurostat 2017; Geiger,Fischer, and Schrader 2018). For instance, of thetotal volume of greenhouse-gas emissions released

CONTACT Marcia Frezza frezza@ztg.tu-berlin.de Center for Technology and Society, Technische Universit€at Berlin, Sekr. HBS 1,Hardenbergstrasse 16-18, Berlin 10623, Germany� 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permitsunrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

SUSTAINABILITY: SCIENCE, PRACTICE AND POLICY2019, VOL. 15, NO. 1, 15–30https://doi.org/10.1080/15487733.2019.1567215

in the United States in 2015 by sector, including dis-tributed electricity, the following sectoral shareswere domestic (16%), commercial (17%), and indus-trial (29%) (USEPA 2017). There is accordingly acompelling need to promote more sustainable life-styles, consumption acts, and routines and with aclear demand for analyses of ‘how and why consum-ers behave as they do’ (Di Giulio et al. 2014, p. 45).Practically speaking, all social practices, classified aseither production or consumption, entail the use ofresources (Røpke 2009; Warde 2005). A distinct linebetween the two realms might not always be easy toestablish because, for example, the transformation ofresources into intermediate products, as well as thedirect use (and discard) of final products occurs inboth business and private domains (Røpke 2009). Inthis article, we define consumption as activities thatinvolve the acquisition, use, and disposal of goodsand services (Kaufmann-Hayoz et al. 2012; Schraderand Belz 2012).

Kastner and Matthies (2014, p. 178) highlight theneed to have educated and motivated consumerswho are able to look for new opportunities for pro-environmental behavior. They claim that for thedesign of policy measures, ‘not only impact relevantbehaviors should be addressed but also general edu-cation for pro-environmental motivation and thussustainable development.’ In this sense, we can per-ceive that work organizations that implement pro-grams which foster sustainable routines duringworking hours (affecting shared meanings, compe-tencies and structures) may contribute to this educa-tion and motivation.

Most studies of understanding and changingenvironmentally relevant actions use mainstreamsocial-psychological approaches where the focus ison the individual level, implying that personalchange is sufficient for social change (Batel et al.2016). Theories and behavioral models could beenhanced by shifting attention from individualactions toward more expansive and contextualbehavioral aspects (Nash et al. 2017) which wouldrequire consideration of the linkage among individ-uals, businesses, governments, and the cultural andphysical contexts of consumption and lifestyles.

Among sociological perspectives, theories of prac-tice (TPs) provide theoretical and methodologicalalternatives to supplement individualistic and reduc-tionistic approaches (Nash et al. 2017; Nicolini2012), presenting new ways of understandinghuman behavior (Reckwitz 2017) and consumption(Warde 2014), including behavioral spillover (Nashet al. 2017). But when explaining consumption prac-tices, TPs equally have limitations and gaps, specific-ally concerning mind and bodily processes (Warde2014) and the role of individuals. To shed light on

such blind spots, social-psychological theories thatelucidate the role of individuals and mental proc-esses can usefully be combined with TPs. In this art-icle, we argue in particular that the identity processtheory (IPT) can provide such a bridge to TPs inunderstanding sustainable consumption behaviorchange and spillover. IPT defines identity as adynamic social process that has intrinsic relations tosocial changes and actions (Jaspal, Nerlich, andCinnirella 2014; Breakwell 2010). The interdepend-ence of identity construction and elements of practi-ces can help explain how routines change and howspillover occurs. According to our extensive litera-ture review, it is the first time the potential combin-ation of TPs and IPT is proposed. Additionally,despite growing research interest in spillover effects,evidence and catalysts for behavioral spillover arestill unclear (Nash et al. 2017).

The guiding question of this article is ‘how canthe combination of identity process theory and the-ories of practice benefit analyses of spillover effects?’As expressed by Klade et al. (2013, p. 322), ‘theworkplace setting together with incentives providedby the company forms an ideal opportunity toorganize daily practices and behavioral routines in amore sustainable and climate-friendly manner.’Accordingly, the framework that we describe aimsto observe and analyze spillover effects, primarily,from the workplace to the domestic environment.With this choice, we acknowledge that work organi-zations have the possibility to systematically struc-ture and implement policies that shape the materialand physical aspects of the workplace, the meaningsand values shared by employees, as well as employ-ees’ skills and competencies necessary for the per-formance of (sustainable) practices. For other actors,as municipalities, it is much more difficult to imple-ment integrative strategies that comprise all practiceelements (S€ußbauer and Sch€afer 2018). In futurestages of this research, we plan to expand the use ofthe framework to study spillover effects fromdomestic settings to the workplace, and betweenother contexts and the domestic sphere.

In the second section, we provide an overview ofstudies on spillover effects, emphasizing their poten-tial for opening innovative pathways toward sustain-ability. We then present in the third section coreconcepts of TPs and describe some of their blindspots. The fourth section describes our decision toinclude an identity theory in our framework andanalyzes the advantages of using IPT. We then inthe fifth section elaborate on why the proposedcombination of TPs and IPT is relevant and discusshow we can assess spillover effects from workplacesto home-settings by applying our framework. In thefinal two sections, we outline the expected

16 M. FREZZA ET AL.

contributions of this conceptual framework andsummarize our key conclusions.

Spillover effect studies: the need forinnovative pathways toward sustainability

Various disciplines including psychology, econom-ics, and sociology have examined spillover effects inhuman behavior and in relation to differentdomains (safety, environment, health, finances),although these effects have previously been charac-terized in diverse ways: ‘response generalization’(Geller 2002; Ludwig and Geller 1997), ‘the foot inthe door effect’ (Beaman et al. 1983; Freedman andFraser 1966), and ‘moral licensing’ (Blanken, van deVen, and Zeelenberg 2015; Mullen and Monin2016). Spillover is the observable and causal effectthat one behavior has on another (Nash et al. 2017;Dolan and Galizzi 2015) and it can be positive(resulting in consistent behavior change) or negative(resulting in inconsistent behavior change). Spilloverstudies either consider the probability that the per-formance of one behavior leads to the performanceof a second behavior (behavioral spillover) or con-sider the probability that the performance of abehavior in one context leads to the performance ofthe same behavior in another context (cross-situ-ational spillover) (Nash et al. 2017).

Research on spillover effects has to date mainlydealt with spillover within the same context and inparticular has tended to focus on domestic settings(Thøgersen and Crompton 2009). To a lesser extent,investigations of spillover have also focused on pro-fessional or workplace contexts and these studieshave typically been concerned with work-life balanceor relationships with colleagues and family members(Cho et al. 2013; Sanz-Vergel and Rodr�ıguez-Mu~noz2013; Tenbrunse et al. 1995) and environmentallyfriendly behaviors (Littleford, Ryley, and Firth 2014;Nik Ramli and Naja 2012; Muster and Schrader2011). Bostr€om et al. (2015) conducted comparativequalitative research in differently sized organizationsof various sectors (hotels/conference venues, trans-port, cinema, interior design, and hospitals/daycare)and concluded that a general organizational sustain-ability/environmental focus, for instance includingsustainability policies, strategies, manuals, and/orcodes of conduct; can help to create a holistic viewthat extends to other areas (e.g. creation of ecola-bels, technical and risk-related schemes, and pro-curement guidelines). Although some researchshows little spillover between workplaces and home-settings (e.g. Littleford et al. 2014), other studiesreport that interventions implemented at workplacesenable positive spillover of consumption patterns todomestic domains (Nik Ramli and Naja 2012;

Muster 2011; Thøgersen and €Olander 2003;Thøgersen 1999) – even though the impact on pri-vate consumption was not a deliberate objective ofthe organizations (Muster 2011).

Our research suggests that identity is likely to beimportant for the occurrence of spillover effects.Similarly, when Dittmer and Blazejewski (2017)investigated spillovers of pro-environmental behav-ior (PEB) from private and public spheres to work-ing spheres, they proposed that environmentalidentity is a key motivational basis for life-workspillover. Additionally, Kastner and Matthies (2014)argue that a pro-environmental motivational basisfor PEB change is key to spillover processes, eventhough high-impact PEBs (i.e. actions that are mostbeneficial for the environment) are less often moti-vated by pro-environmental concern than low-impact actions. The authors argue that drawing onself-perception processes may help to achieve spill-over of higher impact PEBs.

Besides self-identity, previous research has high-lighted self-efficacy as relevant to promoting cross-situational spillover. Dittmer and Blazejewski (2017)found self-esteem and self-efficacy feelings couldplay a role in the establishment of PEB, which arekey concepts that we explore in the proposition ofour framework. Similarly, Littleford et al. (2014)compared two municipal government workplacesand found notable differences between them inadoption of energy-saving behaviors, due primarilyto control factors (e.g. automated lighting) andmaterial factors (i.e. using the same equipment athome and work) may also be a facilitator. They alsofound limited relationships between workplace andhome energy-saving behaviors, although these rela-tionships were stronger in one of the workplaceswhere there was more control over behavior. Theyconcluded that ‘people behave more consistentlyacross settings when they have greater control overtheir own behavior,’ including physical and socialcontrol (p. 165). Other work also suggests home-work spillover may be possible if there is organiza-tional or social support in both environments(Rashid and Mohammad 2011). Additional studiesbring some indications of relationships betweenspillover and identity concepts; however, they didnot directly investigate workplace settings and aremainly related to behavioral spillover (Nash et al.2017; Thomas, Poortinga, and Sautkina 2016; Vander Werff, Steg, and Keizer 2014; Whitmarsh andO’Neill 2010; Thøgersen and €Olander 2006).

Nonetheless, beyond these limited findings,researchers have not explained satisfactorily the con-ditions and processes that underpin (or obstruct)cross-situational spillover effects (Nash et al. 2017);indeed, there remains ‘a lack of detailed

SUSTAINABILITY: SCIENCE, PRACTICE AND POLICY 17

investigation into the mechanisms behind spillovereffects’ (Thomas et al. 2016, p. 127). Furthermore,spillover literature is methodologically limited, par-ticularly relying on behavioral intentions and self-reports, rather than measuring actual behav-ior change.

Along with a need to foster lifestyle changes in amore holistic way to address sustainability chal-lenges, it is also necessary to pursue integrativesocial science that seeks to develop more significantopportunities for reducing emissions at the individ-ual and societal level (Capstick et al. 2014).Accordingly, scholars advocate that there are strongreasons to deepen comprehension of spillover ofsustainable consumption, including from workplacesto private domains (Muster and Schrader 2011) bydrawing on insights from a number of fields.Providing a more interdisciplinary perspective canhelp address some of the criticisms (including fromamong the psychological community) of traditionalpsychological studies on (sustainable) consumptionand spillover effects (Piscicelli 2016; Hargreaves2010; Jackson 2005). For example, Uzzell andR€athzel (2009, p. 341) point out that psychology‘has largely developed individualistic and reduction-ist models of behavior which have rarely positionedbehavior within its larger social, economic and polit-ical context’. Such models provide importantinsights on individuals’ perceptions, cognition, andintentions, but also tend to overlook contextual andnon-conscious drivers of behavior (Piscicelli 2016;Hargreaves 2010; Jackson 2005). This perspectiveimpedes a thorough understanding of the challengesof promoting more sustainable routines. Scholarsfrom theories of practice (TPs) advocate that studiesof consumption should not focus on specific behav-iors, but rather on practices. Practices are importantfor sustainability because through their daily

activities (e.g. cooking and showering) people con-stantly consume resources (Spurling et al. 2013).

Despite epistemological differences, theorists ofboth TPs and social psychology have attempted tobring together these streams where there are areasof convergence, such as around behavior change(Batel et al. 2016), spillover (Nash et al. 2017), andhabits (Kurz et al. 2015). They assert that such com-bination could be fruitful for studies and interven-tions to promote sustainable lifestyles (e.g. Capsticket al. 2014; Boldero and Binder 2013; Darnton andEvans 2013; Heisserer 2013; Darnton et al. 2011;Whitmarsh, O’Neill, and Lorenzoni 2011; Wilsonand Chatterton 2011). We agree that ‘changingthe core unit of analysis and focus, a social practice-based understanding of spillover can bothchallenge and enrich psychologically dominatedperspectives… , [providing insights on] why someactions co-occur and not others’ (Nash et al. 2017,p. 13). Building on these efforts, we here considerthat cross-situational spillover may be another areaof convergence for TPs and social psychology, spe-cifically identity process theory (IPT) that has thepotential to generate insights on transformation ofsustainable consumption routines (Figure 1).

Theories of practice

Theories of practice (TPs) shift the focus fromhuman behavior to social practices. A social practicecan be defined as ‘a routinized type of behaviorwhich consists of several elements, interconnectedto one other… bodily activities, …mental activities,“things” and their use, a background knowledge inthe form of understanding, know-how, states ofemotion and motivational knowledge… a “block”whose existence necessarily depends on the existenceand specific interconnectedness of these elements,

Figure 1. Framework to examine cross-situational spillover (combining identity process theory and theories of practice).

18 M. FREZZA ET AL.

and which cannot be reduced to any one of thesesingle elements’ (Reckwitz 2002, pp. 249–250).

Similarly, Darnton and Evans (2013) describesocial practices as patterns of actions, which bringtogether ‘doings and sayings’ – in particular timesand spaces (see also Nicolini 2012). These ‘doingsand sayings’ are socially shared in routinized ways.There are common features that enable practices tobe coherent, regular, and recognizable in everydaylife (Darnton and Evans 2013). The elements thatconstitute practices are frequently divided into threegroups: materials (e.g. objects, technologies, infra-structure, and the body itself), meanings (e.g. ideas,emotions, aspirations, expectations, and symbolicmeanings) and competencies (e.g. skills, know-how,techniques, and knowledge) (Shove, Pantzar, andWatson 2012; Reckwitz 2002).

In TPs, individuals are characterized as practi-tioners or carriers of practices. Depending on thetheoretical tradition, there might be differences con-cerning the practitioner role or specific characteris-tics. But, generally, TPs define practitioners asknowledgeable and competent carriers who link theelements of the practice (meaning, material, andcompetence) (Mar�echal and Holzemer 2015; Røpke2009). Shove (2012) emphasizes that rather thanacquiring habitual practices, practitioners areacquired or recruited by practices. Thus, TPs takesocial practices as the central focus of interest, mov-ing individuals to the background (Darnton andEvans 2013).

However, TPs are far from being a unified theor-etical body of knowledge. Nicolini (2012, p. 1)emphasizes that TPs can only be perceived as ‘arather broad family of theoretical approaches con-nected by a web of historical and conceptual simi-larities.’ Since practice is a complex, multifaceted,and multi-dimensional phenomenon, the authorobserves that it cannot be grasped by using a singletotalizing discourse; instead, practice should beaddressed through sets of methodological proce-dures (that he terms a ‘toolkit approach’). Based onthis logic, for instance, Nicolini (2009) designed oneof these sets to carry out practice-based organiza-tional studies. He used heterogenous sensitizingconcepts extracted from different TP traditions.

Blind spots in theories of practice

TPs seem, however, to have difficulty in answeringsome key questions. From the perspective of TPs,Shove (2012, p. 100) raises important queries, forinstance, ‘How do habits locate suitable carriers?How do habits, viewed as practices that requirerecurrent, consistent reproduction, relate to otherless demanding pursuits?’ Although TPs shed light

on why certain consumption routines develop andbecome stable, they have thus far delivered littleexplanation for why some practitioners are recruitedby certain practices and others are not. Gram-Hanssen(2015, p. 9) observes that ‘there is a lack of studies onthe social differentiation of practices: why there arevariations within the performance of practices, focus-ing either on the social structuration within the per-formance of practices or on how individuals indifferent socio-materialities or time-spaces performpractices differently’.

The understanding that individuals are merelycarriers of practices (Shove 2012; Shove et al. 2012),a very frequent concept in practice-based studies onsustainable consumption, might contribute to thementioned difficulties. This assumption limits theunderstanding of practice performances because itputs very low emphasis on the role of the individu-als who perform or change practices. Whitmarsh,O’Neill, and Lorenzoni (2011, p. 259) observe thatconcerning transformational and transitional proc-esses, the active participation of people should beconsidered. The authors claim that, ‘unfortunately,there is no “I” (for Individuals) in the…modelShove advocates.’ Warde (2014, p. 294) also analyzessome of the limits that TPs face to explain the rela-tionships among action, body processes, things, andmind. He observes that ‘while acknowledging theneglect of material factors during the cultural turn,maybe the stick is now being bent too far in theopposite direction.’ Additionally, Gram-Hanssen(2015, p. 9) highlights that the ‘need to distancepractice theory research from an individualisticapproach has also led to too much fear of studying(1) how the performances of practices vary betweenpractitioners and (2) how individuals perform prac-tices across particular socio-material settings, includ-ing how individuals also take part inshaping structures’.

We thus conclude that considering contextualand non-human elements is essential, but it is alsoimperative to regard individuals’ roles as an integralpart of practices, even if they are, inevitably,embedded in institutional and physical constraints.In this sense, the application of a theory of identitycan be particularly fruitful to help explain phenom-ena such as those raised by Gram-Hanssen (2015)and thus significantly contribute to practice-basedstudies on sustainable consumption.

Identity process theory

The use of an identity theory to explain motives forand resistance to behavioral change adds potentialnew pathways to favor sustainable behavior.Murtagh, Gatersleben, and Uzzell’s (2012, p. 318)

SUSTAINABILITY: SCIENCE, PRACTICE AND POLICY 19

results ‘suggest rich avenues for future research onthe theoretical and empirical implications of therelationship between identities and sustainablebehaviors.’ Theories of identity have been proposedto understand the (non-)adoption of PEBs (e.g.Jugert et al. 2016; Jaspal, Nerlich, and Cinnirella2014; Uzzell and R€athzel 2009; Lave and Wenger2005; Terry, Hogg, and White 1999). Some studies,more specifically, have sought to explain the mecha-nisms of how spillover works via identity (Nashet al. 2017; Thomas et al. 2016; Van der Werff, Steg,and Keizer 2014; Whitmarsh and O’Neill 2010;Thøgersen and €Olander 2006). Despite the promis-ing findings achieved by the recent attempts toapply theories of identity to comprehend behavioralchange mechanisms toward more sustainable behav-iors (via spillover or not), little attention has beenpaid to the analysis of how interdependencybetween identity construction and structural aspectscan elucidate cross-situational (as opposed to behav-ioral) spillover. Here we consider that a combinedapproach of these two study domains can provide astep forward for the understanding of cross-situ-ational spillover.

For the development of our framework, we firstconsidered four theories related to identity: socialidentity theory (SIT), identity theory (IT), socialrepresentations theory (SRT), and identity processtheory (IPT). We briefly review the first three ofthese theories before demonstrating that IPT pro-vides better conceptual basis for the targetedendeavor. The concept that social structure precedesthe individual and that identity has impacts on peo-ple’s behaviors are in accordance with all four theo-ries, but each theory focuses on different aspects ofidentity. SIT seeks to explain interpersonal andintergroup dynamics, focusing on individual needsand motivations (Breakwell 1993). For SIT, the basefor identity formation is self-categorization and theindividual’s perceptions derived from (inter/out)group relations (Stets and Burke 2000). In IT, roles(e.g. parent, worker) are the basis of identity.According to this theory, society provides roles,which are sets of expectations of behaviors consid-ered appropriate (Hogg, Terry, and White 1995).Self-evaluating the appropriate role-identity, an indi-vidual will act to fulfill the expectations and mean-ings attributed to the role (Stets and Burke 2000).SRT considers that interpersonal communicationprocesses determine the content and structure ofpeople’s belief systems, which are called social repre-sentations. This theory explains that it is throughsocial representations that people interpret and givemeaning to the world (Breakwell 1993). None ofthese three theories, however, focusses on identitybehavior-change processes or adequately accounts

for how behavioral consistency across contexts (e.g.home and work) may be mediated by (change in)identity. On the contrary, there is more attentiongiven to how identities and behavior may differacross, for example, home and workplace due to dif-ferent roles, social groups, or representations associ-ated with each context.

Although, initially, Breakwell (1986) developedIPT to explain how individuals respond to threats toidentities, the author emphasizes that IPT providesa general theory of identity processes (Breakwell2014). Coyle and Murtagh (2014) observe that thereis a wide range of possibilities to extend the use ofIPT, encompassing proactive and constructive iden-tity motivations. Threats to identity are not relevantfor this article, but IPT’s comprehension of identity(its structure, contents, and construction process) iskey to understanding the interdependence of socialchanges and actions, as well as to apprehending thesignificance of spillover effects. IPT is a holistic the-ory that avoids the separation of personal and socialidentities and the concept of multiple identities(Breakwell 2014). According to this theory(Breakwell 1986), identity is a dynamic social prod-uct of the interaction between the individual (con-sidering her/his characteristics and capacities fordeveloping memory, consciousness, and organizedconstruals) and the social context (physical and soci-etal structures and influential processes). This aspectof IPT is of great significance to our research. Inaddition to considering the role of mental activities(e.g. perceptions, interpretations and beliefs) – as theother three theories do – IPT stresses the importanceof physical and social structures to identity con-struction and to the ways people act. Accordingly,comparing the four theories of identity, we concludethat IPT has more to offer for the understanding of(and changes in) routinized performances and spill-over phenomena.

Angouri (2016) observes that, methodologically,identity can either be understood as something indi-viduals have or something individuals do. IPT high-lights that social changes affect identityconstruction; identity construction affects people’sactions; and, simultaneously, actions (re)shape iden-tity (Breakwell 1993). While acting and being partof sociohistoric settings, individuals assimilate thecontent of identity, which defines the salience ofidentity’s characteristics (Breakwell 1986). Thus,identity is not a static entity. Additionally, an indi-vidual’s identity and ways of performing actions arenecessarily interdependent. Identity’s structure andcontents are continuously adjusted and evaluateddepending on interactions with the social environ-ment and ongoing social changes (Sablonni�ere andUsborne 2014).

20 M. FREZZA ET AL.

Identity construction is regulated by two internalprocesses: ‘assimilation-accommodation’ refers toboth the absorption of new elements into identityand the adjustment that occurs in identity structureto make space for new elements and ‘evaluation’refers to the incorporation of value to identity ele-ments (Breakwell 2010). These processes are guidedby at least four principles, which can be describedas desirable states for identity (Breakwell 1993):

� Continuity: The individual will seek (and actaccordingly) to maintain feelings of self-continu-ity and/or group-continuity across timeand space.

� Distinctiveness: The individual will seek (and actaccordingly) to emphasize feelings of uniquenessand differentiation from others (individuals and/or groups).

� Self-esteem: The individual will seek (and actaccordingly) to achieve and maintain feelings ofpersonal and/or group worth.

� Self-efficacy: The individual will seek (and actaccordingly) to achieve and maintain an identitystructure which is characterized by competenceand control over life and situations.

Embedded in social contexts, individuals proceedwith the assimilation-accommodation and evaluationprocesses. If unable to fulfill their desirable states ofcontinuity, distinctiveness, self-esteem, and/or self-efficacy, they will engage in strategies for copingwith the undesirable state(s). Coping strategiesinclude any activities, either thoughts or actions,aimed at modifying the state(s). They can functionat three levels: intrapsychic, interpersonal, or inter-group (Jaspal 2014). In particular, the interpersonaland intergroup levels are relevant to our studybecause they can produce social mobilization, whichcan favor actual changes of practices and, possibly,spillover effects.

An important difference between IPT and theother theories of identity is the fact that it empha-sizes the relevance of the process of identity con-struction, not necessarily stressing the individual’sneed to be perceived as having a specific identitylabel. In relation to this distinction, and consider-ing what Angouri (2016) highlighted, the definitionof identity in IPT would be closer to what peopledo rather to what they have. In other words, thistheoretical perspective explains how social contexts,as well as changes related to physical and societalstructures and influential processes, affect the con-tents and structure of identity. This effect on iden-tity occurs through pursuit of the fulfillment ofidentity principles. Such a process results inthoughts and actions that we could also discern as

‘doings and sayings.’ This understanding providesmissing methodological tools that can enhance thecomprehension of social practice changes and spill-over effects (or how individuals perform practicesacross different social-material settings and particu-larly how they take part in (re)shaping practices).

Framework to analyze spillover effects:combining identity process theory andtheories of practice

Why is the combination of IPT and TPs relevant?

To analyze routines and to intervene toward moresustainable consumption, it is necessary to consideraspects of both social-material structure and the roleof individuals. As has been discussed, psychologicalapproaches tend to focus more on individual deci-sion-making processes than on conditions of dailyroutines, which limits understandings and possibil-ities to intervene. TPs also may constrain under-standing of consumption behavior by putting lowemphasis on the role of individuals. The combin-ation of IPT and TPs is proposed to overcome suchlimitations.

IPT and TPs agree that awareness is a poorground for pro-environmental actions (Thøgersenand Crompton 2009); that habitual behavior androutines are not consciously driven, as they are nota result of rational decision-making processes; andthat the performance of action is made possible bysocial-technical (structural, temporal and spatial)elements (Boldero and Binder 2013; Binder andBoldero 2012; Whitmarsh, O’Neill, and Lorenzoni2011; Jackson 2005). Another aspect that makes thecombination suitable is that both IPT and TPs seekto describe the constitutive aspects, dynamics, andembedded sociohistorical configuration of theirresearch foci. Despite the fact that the core aim ofboth approaches is not behavioral change, in differ-ent ways, IPT and TPs relate to changes in social-historic settings that will co-occur with changes inhabits and routines. This perspective is key toour framework.

A practice-based study or intervention seeks toidentify the available materials, meanings, andcompetencies that allow particular practices torecruit carriers (Kurz et al. 2015). Such mappingof these elements provides a clearer description ofthe structure and dynamics of social changes thataffect identity construction. However, the notionthat individuals (or carriers) are captured (orrecruited) by practices is not enough to explainwhy practices are carried out differently by variousindividuals.

Thus, to better explain the trajectories of practi-ces, and how they are stabilized, adapted, or

SUSTAINABILITY: SCIENCE, PRACTICE AND POLICY 21

abandoned it is also necessary to better explain, asWarde (2014) puts it, individuals’ relevance and therelationships among action, body processes, things,and mind. Additionally, when Reckwitz (2002)defined social practices, he included mental activitiesas one of the constitutive elements. Nash et al.(2017) also describe the significance of TPs tosocial-psychological studies on spillover.Accordingly, we propose the combination of TPsand IPT to design practice-based studies of spill-over effects.

How can we examine spillover effects based onthe combination of IPT and TPs?

One could argue that TPs do not conceptualizespillover, but that they convey understandings thatcan be considered proximate to spillover effects.Schatzki (2015) affirms that practices and theirarrangements bundle through time and space. Ifpractices form bundles, they are connected, despitebeing performed in different time and/or spaces.Consequently, a practice or its elements may affectother practices and their elements, meaning thatthey may prefigure practices and configurations ofthe elements. Accordingly, Nash et al. (2017)observe that there is a ‘loose concept of spillover’ inTPs, because, for example, across different (spatial-temporal) contexts, practitioners engage in the samepractice and, therefore, follow structural rules andprocedures that prefigure similar performances ofthe practice. Røpke (2009, p. 2493) observes thatsocial reproduction ‘is based on the intersection intime and space of institutional projects and individ-ual pathways, sometimes with individuals linked tospecific roles within institutions (e.g. within thefamily or at a workplace).’ Additionally, accordingto Reckwitz (2002), individuals represent a uniquecrossing point of practices.

Hence, we can see in Schatzki (2015), Røpke(2009) and Reckwitz (2002) the implicit importanceof individuals for the realization and understandingof practice trajectories. However, as discussedbefore, TPs do not satisfactorily explain how indi-viduals perform across different social-material set-tings, or how they actively contribute to (re)shapepractices (Gram-Hanssen 2015). Based on our cur-rent literature review, only one published study(Wonneck and Hobson 2017) has applied a prac-tice-based approach to investigate spillover effects,but unlike our work, the authors did not considerthe active role of practitioners.

We present some contributions that IPT providesfor the comprehension of practice trajectories – orspillover effects. First, we observe that the conceptof ‘role’ – mentioned in Røpke (2009) and the key

to some identity theories – favors an understandingabout why some practices may not be reproduced inintersections in space or time. Role identities implythe fulfillment of expectations and appropriatebehaviors prescribed by specific groups and contexts(Stets and Burke 2000; Hogg et al. 1995). Hence,according to role-identity theories, when the indi-vidual crosses different places and/or contexts, s/hewill tend to give salience to the specific roleexpected for that setting. For example, the roles ofbeing a manager at a company and a mother athome imply different practices and/or different waysof performing the same practices. Thus, the focuson ‘roles’ could explain the ‘non-reproduction’ ofpractices across social-material settings – and thenon-occurrence of spillover effects.

In contrast, the processual concept of identity inIPT is suitable to explain the trajectories of practicesacross different settings (spillover). For instance, atwork, an employee is engaged in practices that con-sume water more sustainably. The performance ofsuch routines (being embedded in the availablemeanings, material, and competencies at work)affect the contents of her/his identity – for example,s/he may develop feelings of high self-efficacy andself-esteem because s/he performs practices thatentail sustainable consumption of water. These feel-ings will add content to her/his identity, which willguide the way s/he will act and interact with differ-ent social-material elements. Additionally, as thecarrier who crosses practices in the intersection oftime and space, s/he may seek to maintain, in othersettings – for instance at home – the high levels ofself-esteem and self-efficacy reached at work (andthis may also imply the need for continuity).Accordingly, s/he will seek to engage in strategies(at home) to maintain these high (and satisfactory)levels of the identity principles. While proceedingwith such engagements (and performing differentpractices), s/he will potentially be confronted with(and possibly adapt) the available elements of practi-ces at home (material, meanings, and competencies),as well as to negotiate with the other involved prac-titioners. In this sense, we may identify that thearrangements of practices at work can potentiallyprefigure similar practices at home: while practicearrangements affect the contents of identity, theeffort to maintain the level of identity principlesaffects the way people act/perform, which can con-tribute to reshaping practices (via modifying theirelements or the way practices bundle together).However, the comprehension of practices prefigur-ation (or the spillover effects) between different set-tings (e.g. work and home) will be impaired if theparticipation of the individual (the unique crossingpoint between practices) is neither considered nor

22 M. FREZZA ET AL.

understood. Figure 1 is designed to visually expressthese processes, or, more specifically, the interac-tions and interdependencies among elements ofpractices and identity principles that affect practices.

Describing the framework

Figure 1 depicts our view of processes involved inspillover occurrences, combining IPT and TPs con-cepts. We perceive spillover effects as part of multi-dimensional processes that entail the dynamics ofhow practices are perpetuated, abandoned, and/oradapted, in combination with the intrinsic and con-tinuous strategies of practitioners to fulfill iden-tity principles.

Essentially, spillover effects take place in bothdirections, between different places and lifedomains. Therefore, they occur, for instance, fromhome to the workplace, as well as vice versa (Younget al. 2015; Tudor, Barr, and Gilg 2008). However,the focus of our current research is the study ofspillover effects from the workplace to the homedomain. Correspondingly, in Figure 1, the arrowspoint in this direction.

Two life domains are represented in Figure 1:work (on the left) and home (on the right). In eachdomain, a variety of practices are performed.Accordingly, these practices are shaped by theavailable elements (competencies, material, andmeanings). The framework suggests that if at workpeople perform practices that entail sustainableconsumption, this can potentially affect the waythey perform practices at home. While people per-form practices at work: they deal with instrumentsand objects; they develop competencies and know-how; they reproduce meanings; they negotiate withother practitioners; they conform or resist tonorms; and so forth. In this sense, the specific con-ditions of practice performances and configurationat work will provide elements for identity. Thesocial-material settings, the doings and the sayings,will help define the salience of the characteristics ofidentity and will help establish the standards foridentity principles. The processes that are describedhere are represented by boxes No. 1 and No. 2 inFigure 1.

The work domain in the figure represents a workorganization that creates supportive environmentsfor employees (practitioners) to perform sustainableroutines. Hence, it is expected that, in general,employees will develop high levels of identity princi-ples (self-efficacy, continuity, self-esteem, and dis-tinctiveness) concerning practices that involvesustainable consumption. Since the process of iden-tity construction compels people to strive to main-tain the same level of identity principles across time

and space, it implies that employees will engage instrategies to succeed in achieving satisfactory levelsin different life domains (box No. 2 in Figure 1).

However, people’s actions are embedded insocial-material conditions and elements of practices.Hence, the strategies they engage in will be depend-ent on the conditions and elements available in thedifferent settings they come across. Concerning ourframework (box No. 3 in Figure 1), it means thatwhen people seek to maintain the satisfactory levelsof identity principles (made possible via routines atwork), their actions and performances at home willbe circumscribed by the conditions and elementsavailable in this setting. Accordingly, their strategiesmight entail negotiations, resistances, conflicts,adaptations, and changes concerning the elements ofthe practices, as well as concerning the ways practi-ces bundle together. On one hand, these processeswill possibly favor changes of practice performancesat home, where agency and control are likely to begreater than in the workplace (Littleford et al. 2014).On the other hand, while pursuing strategies andpotential negotiations to adapt and change practicesat home, employees engaged in spillover processesmay have to deal with resistances and conflicts fromother household members who might not have thesame pro-environmental motivations or object todisruption to their routines (e.g. Hargreaves, Nye,and Burgess 2010). Dittmer and Blazejewski (2017)observed that people respond in different wayswhen facing resistance, for instance, by becomingresilient and/or tolerant of frustration or by enhanc-ing their self-esteem. Particularly the last strategymay fortify their determination to perform (andspillover) the practice. To investigate and analyzethe changes that we highlight above, we refer toSpurling et al. (2013). The authors describe six waysin which sustainability challenges can be framed:three in current policy interventions (innovatingtechnology, shifting consumer choices, changingbehavior) and three from a practice perspective (re-crafting practices, substituting practices, changinghow practices interlock). The latter group is of par-ticular interest to our framework because of its link-age to social practices:

� Recrafting practices involve the reduction ofresource intensity of existing practices by chang-ing components or elements, for example, theimplementation of LED lights or the adaptation/employment of competencies.

� Substituting practices involves replacing less sus-tainable practices with more sustainable alterna-tives, for example, substitute car driving byriding a bicycle.

SUSTAINABILITY: SCIENCE, PRACTICE AND POLICY 23

� Changing how practices interlock involves adapt-ing the way different practices bundle together. Itis expected that adjustments can affect severalinterconnected practices, for example, washingclothes (reduction of water consumption), shop-ping (reduction/substitution of washing prod-ucts), and cleaning the house (reuse of wastewater to clean the patio floor).

Because we sought to advance analysis of thespillover of routinized activities from work todomestic settings, we deemed that investigation ofthe substitution of practices was beyond the scopeof our aim. For this reason, we only focused in ourframework on recrafting practices and changinghow practices interlock (Spurling et al. 2013).

Brief illustration of conceptual improvementsprovided by the framework to spillover studies

Using a practice-based approach, Wonneck andHobson (2017) carried out an empirical study(linked to an intervention program) on the spilloverof practices. The authors sought to understandwhether and how certain practices affect each other,analyzing practice composition and relations toother practices. In addition to practical aspectsrelated to materials, competencies, and meaningsinvolved in spillover effects (negative and positive),they verified the occurrence of ‘emotive processes.’By mentioning these ‘emotive processes,’ the authorsstate their relevance for the spillover phenomena tooccur, but they do not explore how these processeswould work, leaving important questionsunanswered, for instance:

� How relevant are these emotive processes for theperformance of practices?

� How and to what extent are the ‘emotive proc-esses’ operators of spillover effects?

� How are these processes and the elements ofpractices linked?

We suggest that the use of our framework couldhelp answer these questions as well as similar ones.We propose that the framework combining IPT andTPs can potentially deepen the comprehension ofspillover of (sustainable) social practices. To betterexplain and exemplify our considerations on thismatter, we elaborate in Table 1 how our frameworkcould favor improved understandings of spillovereffects of social practices.1

The additional brief analyses of some ofWonneck and Hobson’s (2017) results that wedeveloped (third column of Table 1) highlight thatthe identity principles (feelings of self-efficacy, self-

esteem, continuity, and distinctiveness) influence theprobability that spillover effects of practices will(not) occur. For example, in row ‘ii’ of Table 1, des-pite the fact that previously there was the availabilityof competence and material for the ‘practice ofcomposting,’ the overall changes of elements ofpractices seem to have affected feelings related toself-efficacy and self-esteem, which were possiblydeterminant for the partial abandonment of thepractice. We may conclude that TPs alone lack cap-acity to explain essential aspects of the cross-situ-ational spillover of practices. To make significantprogress on spillover studies, it is also relevant toconsider the identity principles that guide identityconstruction. These considerations strengthen ourargument that the combination of IPT and TPs isfruitful to deepen comprehension of reproduction,adaptation, and/or abandonment of social practicesat the intersections of time and space. Thus, inter-ventions that seek to favor the spillover of sustain-able practices also need to take into considerationthe interrelation of identity principles and (changesof) the elements of practices.

Expected major achievements of the framework

Sustainability is a multilayered issue and to pursuesolutions to environmental problems it is necessaryto consider levels of both social structures and indi-vidual actions (Whitmarsh, O’Neill, and Lorenzoni2011). The two dimensions are necessary, but nei-ther one is sufficient on its own to determine path-ways toward more sustainable consumptionroutines. Additionally, sustainable consumptionstudies need to conceptualize the relationshipsamong individual aspects, elements of practice, andstructural contexts (Capstick et al. 2014). It is, there-fore, necessary to seek synergies between theoreticalconcepts, an effort that we strive to make here bycombining concepts of IPT and TPs.

The specific combination of IPT and TPs that wehave developed is in accordance with previous workthat has pointed out the benefits of combining TPsand psychology, as well as concerning the under-standing of spillover phenomena (e.g. Nash et al.2017). In the current case, though, we have appliedthese two fields to cross-situational spillover, a par-ticular form of spillover that has received far lessattention than behavioral spillover. Our purpose isneither to integrate both streams nor to develop aunified theory but to find synergies between IPTand TPs, without risking their coherence, consist-ency, and independence. In that sense, in the previ-ous sections, we accomplished our intention toexplain the relationships among the elements of

24 M. FREZZA ET AL.

practices, actions, identity principles, and spill-over effects.

Work organizations have the possibility of shap-ing material structures, meanings, norms, and com-petencies of practices at worksites, which can createsupportive environments for practitioners to per-form sustainable routines (S€ußbauer and Sch€afer2018; Bostr€om et al. 2015). Additionally, previousstudies have identified positive spillover effectsbetween work and home domains. Therefore, it isdesirable to develop studies and interventions thatincrease the potential of organizations to affect indi-vidual consumption routines at workplaces and inprivate spheres (e.g. favoring positive spillover ofsustainable consumption practices). We contendthat the combination of IPT and TPs applied tostudies of cross-situational spillover of sustainablepractices – the framework we present here – cancontribute to such endeavors.

By developing this conceptual framework wehave sought to generate new insights into analysesof spillover effects of sustainable routines – forexample, the spillover of practices that entail con-sumption (of products, infrastructures, and services)and its different stages (acquisition, purchase, use,and disposal) between workplaces and home set-tings. In addition, we suggested how the frameworkcan be analytically applied to empirical studies that

focus on spillover effects of sustainable consumptionroutines. As such, the framework addresses gapsand challenges mentioned in the literature, such asthe need, highlighted for instance by Jaspal, Nerlich,and Cinnirella (2014) to develop empirical studiesthat seek to examine the interrelations betweensocial practices and identity processes in contextsthat aim at transitions to more sustainable lifestyles.

The framework focuses on spillover effects andchanges of practices toward more sustainable con-sumption routines and the aspects that favor suchphenomena, including, for example, material ele-ments and individuals’ relevance. Accordingly, theframework speaks to another gap mentioned in theliterature, namely the need to explain how individu-als perform practices across different social-materialsettings and how they take part in (re)shaping struc-tures (Gram-Hanssen 2015).

Focusing on both the elements of practice andidentity principles, the use of our frameworkencourages researchers to use forms of observingand interacting with the research object. The frame-work facilitates the use of several methodologicaltools and techniques – participant observations, dif-ferent types of interviews, questionnaires, and com-parison of different sources of data (diaries, fieldnotes, audio, and video recordings). Such applica-tion of the framework contributes to improved

Table 1. Insights of how the use of identity process theory can deepen analyses of spillover effects of social practices.

Some aspects of Wonneck and Hobson (2017) results using TPs Contributions of our framework combining TPs andIPT to deepen the analysis

Spillover effects Practitioners’ explanationsThe relevance of identity principles for spillover

effects of social practices

i. As an effect of the intervention, prac-titioners reported they dry recyclemore, both at home and elsewhere.

a) After getting used to separating foodand yard waste, practitioners ‘felt itwas weird’ to see dry recyclables inthe garbage bin.

This result may indicate the relevance of practitioners’ desiresfor continuity. We assume that practitioners were seeking tomaintain feelings of self-continuity, which could have favoredthe occurrence of spillover effects of practices.

b) The intervention program ‘forced’practitioners to reflect and developtechniques for separating the waste.

This example may express the importance of feelings of self-effi-cacy for the occurrence of spillover. Affected by competenciesof practices installed by the intervention, practitioners mighthave developed feelings of self-efficacy and sought to main-tain control over other situations (reshaping practices andtheir elements).

ii. The intervention program involvedthe collection of composting wastedelivered to an industrial-scale com-posting facility. With this interven-tion, some practitioners reportedthey significantly reduced or stoppedhome composting.

c) Related to home composting, somepractitioners claimed they were notskilled at making good soil; they alsofound it difficult to keep pests away.

It seems that practitioners felt a lack of self-efficacy. Possibly thecompetencies available within social practices were unable todeliver a desirable level of feeling competent. This under-standing might express how important it is, for spillover tooccur, that practitioners feel able to maintain a satisfactorylevel of self-efficacy, which may also be relevant for practicesto recruit carriers and to stabilize.

d) Some practitioners had the feelingthat home compostingwas ‘pointless’.

Since waste would be composted in any way by the program, itmight have favored the perception that home composting is‘pointless’. In that sense, practitioners that used to homecompost might have felt that they did not make a differenceanymore in terms of sustainability impacts, which might havefavored feelings of lack of distinctiveness. And this lack of dis-tinctiveness contributed to changes in ways of dealing withwaste. Additionally, feelings of doing something ‘pointless’can be linked to feelings of low self-esteem as well as lowself-efficacy. Without being able to maintain satisfactory levelsof self-esteem, self-efficacy, and distinctiveness, practitionersperformed in ways that contributed to the abandonment ofthe practice. In that sense, the practice was unable to con-tinue recruiting the same/new carriers.

SUSTAINABILITY: SCIENCE, PRACTICE AND POLICY 25

methodological strategies, offering, for example, fur-ther possibilities of triangulation, thus strengtheningthe results of the research.

Conclusion

Our conceptual discussion results from a criticalreview of sociological and psychological literatureon practices that are relevant with respect to envir-onmental and sustainability policies. The analysisreveals that the combination of IPT and TPs iscoherent, and it can potentially contribute to newinsights in empirical studies on spillover effects ofsustainable consumption routines. Additionally, ourreview is the first time that the combination of IPTand TPs has been proposed. Inspired by Nicolini’s(2009) warning that, social practices cannot beunderstood using a single totalizing discourse, wesought to develop an interdisciplinary approach.With such an endeavor, we have sought to addresssome weaknesses of previous studies, such as thefocus on individualistic attitudes and perceptions,lack of material dimensions, underestimation and/oroverestimation of people’s agency, and dichotomousperspectives. We deem that the framework can con-tribute to studies that seek to provide more compre-hensive answers to questions about how practicescapture suitable practitioners, how performances ofpractices vary among spatial-temporal settings and/or among practitioners, and how practices relate toother practices.

Additionally, we hope the concepts that weadvance here will contribute toward development ofclearer methodological instruments aimed atexplaining spillover effects, equally encompassingindividual and structural aspects. By not focusing onone behavior at a time, the framework favors theanalysis of far-reaching changes in lifestyles. Seekingto assess the benefits of this approach, we have pro-vided an initial test of the framework in relation topost-hoc analysis of an empirical study. Future workshould seek to apply the framework at the outset ofa spillover study, designing both a spillover inter-vention and its evaluation with these two theoreticalstrands and associated methodologies in mind. Inaddition to providing sensitizing categories forunderstanding mechanisms that favor (or obstruct)spillover phenomena, the framework can also beapplied in future studies on spillover effects in abroader sense, for instance, between different lifedomains and/or different practices. It can also con-tribute to studies aimed at providing further explan-ations of identity construction (and the changes/threats imposed to identity) and on trajectories ofpractices. More broadly, we anticipate that theframework could be used as a theoretical and

methodological tool for designing studies and inter-ventions with wide and diverse foci, aims, andapplications.

Note

1. We emphasize that the ideas presented in Table 1are preliminary suggestions. For a more consistentanalysis, access to primary data and additionalempirical analyses would be necessary. Ourintention is to demonstrate how the combination ofTPs and IPT can provide a deeper and broaderunderstanding of spillover occurrences, drawing onsome results reported by Wonneck andHobson (2017).

Acknowledgments

We cordially thank the institutions that supported thisresearch, as well as the researchers who kindly providedrelevant comments on earlier versions of the article. Wealso thank the editor and the anonymous reviewers fortheir contributions to the improvement of this article.

Disclosure statement

The authors declare no potential conflicts of interest withrespect to the research, authorship, and/or publication ofthis article.

Funding

This research was conducted with the support of theNational Council of Science and TechnologicalDevelopment (CNPq), Brazil, and the Universidade deFortaleza (UNIFOR), Brazil. We acknowledge support bythe German Research Foundation and the Open AccessPublication Funds of Technische Universit€at Berlin.

ORCID

Marcia Frezza http://orcid.org/0000-0003-2880-381XLorraine Whitmarsh http://orcid.org/0000-0002-9054-1040Martina Sch€afer http://orcid.org/0000-0003-2240-6928

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