Review Reports - Intergroup Sensitivity and Promoting Sustainable Consumption: Meat Eaters Reject Vegans’ Call for a Plant-Based Diet

Round 1

Reviewer 1 Report

I appreciate the opportunity to review this interesting article. Here are some suggestions that could improve it.

1. Introduction

- I believe that some statements, such as the first sentence of the article, require greater endorsement in the scientific literature than just a single quote.
- Consider whether it is necessary to differentiate between the type of meat that mainly contributes to climatic problems, for example beef or pork, and poultry.
- Consider including other arguments in favor of not consuming meat, not just climactic ones. For example, the possible relationship of consuming certain types of meat with the increased risk of colon cancer or other disorders.
- The section "present research" does not make much sense because such information is already in the methods section, unless it is a requirement of the journal.

2.- Methods.

- Explain, justify and comment on the possible effect on the results of the disproportion in the sample between the number of men and women.
- It would be necessary to justify who determines the content validity of the texts / articles used in the research.
- Apparently the texts only identify problems with climate change and not other aspects, such as health problems due to eating meat ... Could the results be influenced by the fact that the texts were not sufficiently critical and forceful with the consumption of meat? Could clearer and "meat-aggressive" texts have influenced the results in another way?

3.- Results and discussion

- Include comments, explanations and justification, regarding the effect of the aspects indicated in these suggestions and their possible effect on the results and conclusions.

Author Response

Response to Reviewer 1

Thank you for your constructive feedback and positive evaluation of our paper. We have substantially revised our manuscript and respond to each of your comments below. One co-author, who is a native speaker, has carefully proof-read the manuscript.

Reviewer 1 Comment 1: I appreciate the opportunity to review this interesting article. Here are some suggestions that could improve it.

Introduction

- I believe that some statements, such as the first sentence of the article, require greater endorsement in the scientific literature than just a single quote.

- Consider whether it is necessary to differentiate between the type of meat that mainly contributes to climatic problems, for example beef or pork, and poultry.

- Consider including other arguments in favor of not consuming meat, not just climactic ones. For example, the possible relationship of consuming certain types of meat with the increased risk of colon cancer or other disorders.

- The section "present research" does not make much sense because such information is already in the methods section, unless it is a requirement of the journal.

Author Response 1: Thank you for this suggestion. We have now extended our references accordingly (p. 16 f.). We have also now addressed the differentiation between types of meat in the limitations section and discuss whether more differentiated suggestions for behaviour change would be more effective. We also discuss how addressing other benefits of not consuming meat in critical comments could impact the observed results. Please note that we have rearranged the structure of the paper in line with the suggestions of Reviewer 2. We shortened the section “present research” and integrated it in the introduction. (p. 2)

Quote 1. “We also did not distinguish between different types of meat, although the negative effects of meat consumption on the environment and personal health vary greatly [70, 71]. For instance, red meat (i.e., beef and veal) has a greater carbon footprint than poultry [72]. The reduction of the consumption of a specific type of meat would therefore be most beneficial. Such an approach may be less effective, however, due to the added complexity level, which may present further hindrances to behavior change. Combining both personal and environmental benefits of reduced meat consumption in one message and referring to the consumption of specific types of meat are thus a fruitful avenue for future research.” (p. 15)

Quote 2. “Our comments promoted reducing meat consumption only via environmental appeals. This kind of dietary change also has great personal benefits, for instance by promoting health and decreasing obesity [6]. Including these aspects in comments would play on the societal norms for healthy living [68] and rampant obesity bias [69], making them more “meat-aggressive”.” (p.15)

Reviewer 1 Comment 2: 2.- Methods.

- Explain, justify and comment on the possible effect on the results of the disproportion in the sample between the number of men and women.

- It would be necessary to justify who determines the content validity of the texts / articles used in the research.

- Apparently the texts only identify problems with climate change and not other aspects, such as health problems due to eating meat ... Could the results be influenced by the fact that the texts were not sufficiently critical and forceful with the consumption of meat? Could clearer and "meat-aggressive" texts have influenced the results in another way?

Author Response 2: We respond to your points raised in turn. Women made up 70 % of our sample, and we discuss possible effects of this on our results. We have moreover simplified the sample description (p. 5).

Quote 3. “Our sample provided sufficient power to test our hypotheses but was comprised of students and working adults who were predominantly female. Past research has observed the ISE using samples more representative of the general population [25], across a range of cultures [26, 58, 59], and in all genders [23, 54]. Females have been observed to consume less meat and have more positive attitudes towards veganism than males [60]. The predominance of female participants in our sample may thus have reduced the effect of our manipulation, providing a highly critical test of our hypothesis. Supporting this view, we observed that the ISE was more pronounced among those dedicated to environmentally friendly behaviors. We therefore assume that the observed results will generalize to populations with a greater gender balance.” (p. 14)

The comments and articles used in the research were designed according to common criticism of eating meat, for example in the WHO’s IPCC Report of 2019, which we now note in the paper.

Quote 4. “In fact, we wrote the criticism based on common guidelines to reduce meat consumption [45].” (p. 6)

We have now added a paragraph in which we discuss how using more “meat-aggressive” messages could impact our results.

Quote 5. “Our comments promoted reducing meat consumption only via environmental appeals. This kind of dietary change also has great personal benefits, for instance by promoting health and decreasing obesity [6]. Including these aspects in comments would play on the societal norms for healthy living [68] and rampant obesity bias [69], making them more “meat-aggressive”. The ISE has been observed for critical but not for neutral or positive messages [25]. We would therefore assume that more “meat-aggressive” messages would increase the effect size of our comment source manipulation. We also did not distinguish between different types of meat, although the negative effects of meat consumption on the environment and personal health vary greatly [70, 71]. For instance, red meat (i.e., beef and veal) has a greater carbon footprint than poultry [72]. The reduction of the consumption of a specific type of meat would therefore be most beneficial. Such an approach may be less effective, however, due to the added complexity level, which may present further hindrances to behavior change. Combining both personal and environmental benefits of reduced meat consumption in one message and referring to the consumption of specific types of meat are thus a fruitful avenue for future research.” (p. 15)

Reviewer 1 Comment 3: 3.- Results and discussion

- Include comments, explanations and justification, regarding the effect of the aspects indicated in these suggestions and their possible effect on the results and conclusions.

Author Response 3: We revised the results and discussion sections accordingly, with a more thorough discussion of the limitations and according need for future research. (See Quotes 3, 4 and 5)

Response to Reviewer 2

Thank you for serving as a reviewer on our manuscript and for your supportive comments.

Reviewer 2 Comment 1: Thank you for the opportunity to read your manuscript. The topic is particularly relevant in present days, the method was very well chosen, the hypotheses and argument are relevant and valid. So, the article has potential to attract readers and make a contribution to the field.

Still, there are some weaknesses that need urgent attention from the Authors. Below I provide some comments and recommendations, which I hope are helpful to improve the manuscript. I wish all the best to the Authors and their research.

Structure. The structure of the article is neither adequate nor effective. In my opinion, by following the traditional structure of Sustainability journal articles, the manuscript would benefit not only in terms of clarity, but also on its potential to attract readers and influence the state of the art. Hence, I recommend that the structure is improved. 1. Introduction should provide the contextualization of the topic, and present the arguments, research problem, and objectives. Then, a brief summary of the method adopted, and, if possible, also 1 paragraph emphasizing the main contributions (or innovation) of the article. Again, the study is very interesting and very strong, so this should be easily achieved by the Authors. Then, please include a proper section for the literature review, moving some parts previously included in the introduction. Consequently, the method section will become section 3, and results section 4. The discussion could be integrated in the results, or the conclusion, or become an independent section. Please check the recommendations by Sustainability regarding the discussion. Finally, section 5 (or 6?) would be conclusion, which should have a few sub-sections in this order: 5.1. theoretical contributions; 5.2. practical contributions; 5.3. Limitations and future research directions. Please arrange the numbering if necessary.

Author Response 1: Thank you for bringing this up. We have re-arranged the paper accordingly. Specifically, we now include the sections: literature review (p. 3 f.) and conclusion (p. 11) with the suggested sub-sections: theoretical contributions (p. 12), practical contributions (p. 13) and limitations and future research (p. 14).

Reviewer 2 Comment 2: The literature review is short and should be improved, by including the most recent and relevant articles on the topic. This version of the article has in total 37 references, many of them web links. So, there is a need to include more journal articles. Obviously, the theme of plant-based diet adoption is particularly popular in recent years, including in Sustainability journal, so many relevant contributions would be relevant to include. Therefore, I recommend that the Authors make the literature review stronger, by further supporting the research hypotheses and by integrating more citations of journal articles in line with the arguments and statements made.

Author Response 2: Thank you for this suggestion. We now discuss existing literature more thoroughly, as reflected in our extended reference list (p. 16 f.). Specifically, we pick up on recent debates in Sustainability on environmental behaviour and meat consumption as well as existing literature on the role of social identity.

Quote 6: “Our norm manipulation was adapted from past research but had a limited impact on our dependent measures (i.e., descriptive results were in the expected direction but no significant differences emerged), providing weak support for Hypothesis 2. Potentially, the order of the manipulations decreased the normative impact. Participants viewed the criticism after the norm induction, thus leading to a more immediate impact of criticism on responses. Moreover, our supportive norm manipulation indicated that a growing minority adheres to a meat-free diet. A stronger manipulation indicating that a majority adheres to such a diet could yield larger effects, although such a statement would be factually incorrect and thus would require further deception. In line with our findings, a number of recent studies did not observe beneficial norm effects [61-63] or even reported that norms may backfire [64]. Apparently, the activation of social norms does not always influence behavior, depending on individual and situational factors. For instance, social norm interventions had a greater effect on people scoring high on agreeableness, extraversion, and conscientiousness and low on openness [65]. Other research found that norms had a greater impact on behavior when phrased as an invitation to work together [51]. Alternatively, the violation of a general norm of not criticizing other groups may trump other normative signals, such as the dietary behavior of other citizens. Two recent registered reports support such a normative account of intergroup sensitivity [23, 54], indicating that intergroup criticism violates general conversational norms [29]. Accordingly, future research should investigate the role of the specific content and ordering of norm manipulations, as well as consider people’s individual sensitivity to them.” (p. 14)

Reviewer 2 Comment 3: The discussion does not have any "dialogue" with extant literature, and that is essential to "discuss" your results. Please improve this section, by comparing your findings and arguments with extant literature.

The same applies to theoretical contributions. In order to demonstrate what you add to the state of the art, you need to "compare" with extant literature. Please refer to the most relevant and recent articles too.

In my opinion part of the limitations you point out should be integrated in the discussion... The limitations of your study are, for instance, the poor nature of your sample (student sample). Also, please provide recommendations for future research.

Author Response 3: Thank you for pointing this out. We have added a discussion of the limitations you point out. The share of students in our sample is higher than in the general population (44,7 %), it does not reflect the majority in our sample. Our participants were predominantly female (70 %). We now provide extended sample demographics and discuss why we are optimistic that our findings will generalize to other contexts and populations.

Quote 7: “N = 260 participants were included in the analysis (185 female, 73 male, 2 divers, age M = 30.60, SD = 11.47, 128 Austrian, 120 German, 12 other nationality; 122 working, 115 students, 23 other.)” (p. 5)

Quote 8: “Our sample provided sufficient power to test our hypotheses but was comprised of students and working adults who were predominantly female. Past research has observed the ISE using samples more representative of the general population [25], across a range of cultures [26, 58, 59], and in all genders [23, 54]. Females have been observed to consume less meat and have more positive attitudes towards veganism than males [60]. The predominance of female participants in our sample may thus have reduced the effect of our manipulation, providing a highly critical test of our hypothesis. Supporting this view, we observed that the ISE was more pronounced among those dedicated to environmentally friendly behaviors. We therefore assume that the observed results will generalize to populations with a greater gender balance.” (p. 14)

Quote 9: “Along similar lines of reasoning, our study did not include a direct measure of meat consumption after viewing the criticism. This said, changing attitudes and intentions are important precursors of behavior change and our research thus indicates that investigating the behavioral impact of public messaging campaigns on actual consumption is a fruitful avenue for future applied research.” (p. 15)

As for other recommendations for future research, we provide strong causal evidence due to our experimental manipulation using a behavioural measure. However, we do not directly assess meat consumption. Future research should thus observe consumption behaviour directly.

Thank you again for serving as a reviewer and your constructive feedback. We hope that you agree that this round of revisions has substantially improved our manuscript.

Author Response File: Author Response.pdf

Reviewer 2 Report

Thank you for the opportunity to read your manuscript. The topic is particularly relevant in present days, the method was very well chosen, the hypotheses and argument are relevant and valid. So, the article has potential to attract readers and make a contribution to the field.

Structure. The structure of the article is neither adequate nor effective. In my opinion, by following the traditional structure of Sustainability journal articles, the manuscript would benefit not only in terms of clarity, but also on its potential to attract readers and influence the state of the art. Hence, I recommend that the structure is improved. 1. Introduction should provide the contextualization of the topic, and present the arguments, research problem, and objectives. Then, a brief summary of the method adopted, and, if possible, also 1 paragraph emphasizing the main contributions (or innovation) of the article. Again, the study is very interesting and very strong, so this should be easily achieved by the Authors. Then, please include a proper section for the literature review, moving some parts previously included in the introduction. Consequently, the method section will become section 3, and results section 4. The discussion could be integrated in the results, or the conclusion, or become an independent section. Please check the recommendations by Sustainability regarding the discussion. Finally, section 5 (or 6?) would be conclusion, which should have a few sub-sections in this order: 5.1. theoretical contributions; 5.2. practical contributions; 5.3. Limitations and future research directions. Please arrange the numbering if necessary.
The literature review is short and should be improved, by including the most recent and relevant articles on the topic. This version of the article has in total 37 references, many of them web links. So, there is a need to include more journal articles. Obviously, the theme of plant-based diet adoption is particularly popular in recent years, including in Sustainability journal, so many relevant contributions would be relevant to include. Therefore, I recommend that the Authors make the literature review stronger, by further supporting the research hypotheses and by integrating more citations of journal articles in line with the arguments and statements made.
The discussion does not have any "dialogue" with extant literature, and that is essential to "discuss" your results. Please improve this section, by comparing your findings and arguments with extant literature.
The same applies to theoretical contributions. In order to demonstrate what you add to the state of the art, you need to "compare" with extant literature. Please refer to the most relevant and recent articles too.
In my opinion part of the limitations you point out should be integrated in the discussion... The limitations of your study are, for instance, the poor nature of your sample (student sample). Also, please provide recommendations for future research.

Best wishes, and happy new year.

Author Response

Response to Reviewer 2

Thank you for serving as a reviewer on our manuscript and for your supportive comments. We have substantially revised our manuscript and one co-author, who is a native speaker, proof-read the manuscript. We respond to each of your comments below.

Thank you again for serving as a reviewer and your constructive feedback. We hope that you agree that this round of revisions has substantially improved our manuscript.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Thanks for the careful revision. Clearly, the improvements made the article much stronger. I wish all the best to the authors and their research.