Peer Review History

Original SubmissionOctober 4, 2019
Decision Letter - Catharine Penelope Cross, Editor

PONE-D-19-27807

NO EVIDENCE THAT OMISSION AND CONFIRMATION BIASES AFFECT THE PERCEPTION AND RECALL OF VACCINE-RELATED INFORMATION

PLOS ONE

Dear Mr Jimenez,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

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Kind regards,

Catharine Penelope Cross

Academic Editor

PLOS ONE

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Additional Editor Comments (if provided):

Dear Mr Jiménez

I have now received two very favourable reviews of your manuscript and have read it carefully myself. I think it is very close to being ready to publish.

Both reviewers made suggestions for improving the paper further, however, and I have one or two myself. I have complied these suggestions into an outline here and would also encourage you to read the original comments of both reviewers in full.

Additional citations:

R1 made some suggestions of papers on vaccine attitudes which you might wish to cite. I’d encourage you to have a look at these, though I’ll leave it up to you which ones you feel would really add to the paper. If R1 is right, however, the suggestion they make regarding a tweak to line 210 would be particularly relevant, as it would link to something directly relevant to your study.

Analysis:

R1 reported having some difficulty following your results section. I think it might be worth (if possible) adding a citation to similar analyses/guides to such analyses for readers not familiar with the AIC approach. In particular, I think the use of the word ‘logistic’ threw R1 off the trail a bit: it seems they believed you had tested a yes/no of whether each ppt recalled each item, rather than testing proportions recalled correctly (I went to confirm what you’d done by looking at the variable ‘Recall’ and its range in the supplementary material). It might be worth adding a clarifying sentence or two in the main text to walk readers through the analysis process a little more slowly.

Preregistration details:

R2 noted that pre-registration is a particular strength of the paper. They seem not to have located the scripts and data in supplementary material, but I think these will be much more findable when the paper is nicely formatted and online. I had a look and they seem clear and thorough to me.

R2 did note that the dates of data collection don’t seem to be given in the paper, and I can’t find them either. Please could you specify the period of data collection in the main text?

R2 also suggests that there should be a clearer marking of analyses that are and are not part of the pre-registered plan. I note that these are marked in the R scripts, but would ideally like to see a brief note of this in (the results section of) the main text as well.

Power

Finally, R2 noted the age-old problem of inferring a negative from a null result, and suggested that if the ‘true’ effect is small then N=202 might actually miss it. Please could you tweak the sentence that R2 notes in their review and any similar ones accordingly. An additional suggestion from me would be to discuss the range of plausible effect sizes according to the analysis, as well as reporting whether or not a predictor is part of a best-fitting model. Joe Stubbersfield does this in the main text and supplementary material of this paper: Stubbersfield, J. M., Dean, L. G., Sheikh, S., Laland, K. N., & Cross, C. P. (2019). Social transmission favours the ‘morally good’over the ‘merely arousing’. Palgrave Communications, 5(1), 3.

Gender of participants

I found the (quite interesting!) rationale for testing only female participants in the supplementary material, but I think it’s worth mentioning briefly in the main text because many readers will wonder about it.

I hope these suggestions are helpful. I’ll be happy to clarify any that require it. I look forward to receiving your revision – I think this paper will be a valuable addition to the literature.

Best wishes

Kate Cross

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: No

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: I uploaded my review as an attachment.

I uploaded my review as an attachment.

I uploaded my review as an attachment. (Couldn't submit the manuscript if this section was left under 200 characters)

Reviewer #2: The manuscript is clear, the research well motivated and thoroughly carried out, the results presented clearly. It is important that these results are published.

I have three recommendations which I think are important to see the full value of this work realised

1. Regarding Pre-registration

The preregistration of the analysis is a great thing and the authors could make more of it (since it is a strength of an analysis with several DVs and multiple plausible analysis pathways for the exact analysis to be pre-declared).

Regardless of whether the authors decide to emphasise the pre-registration they should#

A Clearly distinguish pre-registered analyses from exploratory analyses in the results

B Clarify the timeline: the ethics for this project was given June 2016, the pre-registration is dated Dec 2017, but timestamped Feb 2018. When was the data collected? This information should be declared

2. Open Data

Why not make the data (and final analysis code) from this study available?

3. Risk of false negatives

The authors should discuss the possibility that their null results are false negatives. In particular, a statistical power analysis of a between subjects contrast will reveal that n=202 is not actually that many for detecting small to medium effects. The consequence of this must be to weaken the conclusion that this study is evidence of lack of omission bias (i.e. it elevates the plausibility that the study is merely a lack of evidence regarding the presence of an omission bias). So, for example, a sentence like this should be revised or qualified "The lack of evidence for the omission bias indicates the nonexistence of such a bias or the elimination of its effects in modern environments."

**********

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Reviewer #1: Yes: Sacha Altay

Reviewer #2: Yes: Tom Stafford

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Attachments
Attachment
Submitted filename: Review.docx
Revision 1

Thank you for your comments and suggestions. We have included a response to your comments on the Response to Reviewers. We also include our response here:

# EDITOR

R1 made some suggestions of papers on vaccine attitudes which you might wish to cite. I’d encourage you to have a look at these, though I’ll leave it up to you which ones you feel would really add to the paper. If R1 is right, however, the suggestion they make regarding a tweak to line 210 would be particularly relevant, as it would link to something directly relevant to your study.

R1 is right: the study does not provide evidence to rule out the disgust-antivaccination link. Consequently, we have changed the sentence to be more specific to the omission bias: “the lack of convincing evidence for the omission bias suggest that the spread of anti-vaccination messages might not be explained by an omission bias acting against the practice of vaccination” (lines 535-537). We do not comment on the disgust-antivaccination link, as this is not the topic of our article.

We have also added one of the suggested references on vaccine communication. We don’t think we need to specifically address the literature on vaccine communication as the article focuses on cognitive biases, not in specific interventions to make pro-vaccination messages more appealing.

Analysis:

R1 reported having some difficulty following your results section. I think it might be worth (if possible) adding a citation to similar analyses/guides to such analyses for readers not familiar with the AIC approach. In particular, I think the use of the word ‘logistic’ threw R1 off the trail a bit: it seems they believed you had tested a yes/no of whether each ppt recalled each item, rather than testing proportions recalled correctly (I went to confirm what you’d done by looking at the variable ‘Recall’ and its range in the supplementary material). It might be worth adding a clarifying sentence or two in the main text to walk readers through the analysis process a little more slowly.

We have added a few sentences to explain how model comparisons work: “For our analyses of average severity ratings, we adopted a model comparison approach (Burhmam and Anderson, 2002). We first ran a null linear model that used a fixed intercept (i.e. the mean of the outcome variable) to predict each participants’ average severity ratings. We compared this null model with two linear regression models directly derived from our hypotheses using Akaike’s Information Criterion (AIC, see Table 2). A lower AIC by a difference of two or larger was considered evidence of better fit to the data” (Lines 382-391).

We have also added a reference to a classical book on the use of AIC for model comparisons and statistical inference:

Burnham, K. P., & Anderson, D. R. (2002). Model Selection and Multi-Model Inference: A Practical Information-Theoretic Approach. Secaucus, US: Springer.

We have also added a few sentences to be clearer about our use of logistic regression for a proportional outcome and added a reference about how to conduct this type of regression model: “For our analyses of recall, we use the same model comparison approach as for the analyses of average severity ratings. As our outcome variable was the proportion of correctly recalled symptoms/side effects, we modelled the relationship between the predictors and the outcome variables using logistic regression models for a proportional outcome (Zuur, Ieno, Saveliev, Smitt & Walker, 2009, pp. 254-257). The fit of a null model was compared with our confirmatory models (see Table 3)” (Lines 414-419).

R2 noted that pre-registration is a particular strength of the paper. They seem not to have located the scripts and data in supplementary material, but I think these will be much more findable when the paper is nicely formatted and online. I had a look and they seem clear and thorough to me.

The data and the R scripts were submitted together with the manuscript. We want the data and R scripts to be accessible for everybody together with the article on PlosOne’s website.

R2 did note that the dates of data collection don’t seem to be given in the paper, and I can’t find them either. Please could you specify the period of data collection in the main text?

We have added a sentence (Lines 276-277) with the dates of data collection (5th March and 31st March 2018).

R2 also suggests that there should be a clearer marking of analyses that are and are not part of the pre-registered plan. I note that these are marked in the R scripts, but would ideally like to see a brief note of this in (the results section of) the main text as well.

We have provided a more extended explanation of the changes conducted in the data analyses with respect to the preregistered analyses at the beginning of the Results section. Specifically, we report that we are not reporting regression models with interaction terms without main effect terms due to their controversial nature in statistics. We explain that instead we report regression models with both main effect and interaction terms. We also note that this change has not qualitatively affected the results and provide both analyses as supplementary materials so that the readers can check this by themselves.

Power

Finally, R2 noted the age-old problem of inferring a negative from a null result, and suggested that if the ‘true’ effect is small then N=202 might actually miss it. Please could you tweak the sentence that R2 notes in their review and any similar ones accordingly. An additional suggestion from me would be to discuss the range of plausible effect sizes according to the analysis, as well as reporting whether or not a predictor is part of a best-fitting model. Joe Stubbersfield does this in the main text and supplementary material of this paper: Stubbersfield, J. M., Dean, L. G., Sheikh, S., Laland, K. N., & Cross, C. P. (2019). Social transmission favours the ‘morally good’over the ‘merely arousing’. Palgrave Communications, 5(1), 3.

As suggested, we have qualified the statement “The lack of evidence for the omission bias indicates the nonexistence of such a bias or the elimination of its effects in modern environments” by changing it to “The lack of evidence for the omission bias MIGHT INDICATE the nonexistence of such a bias or the elimination of its effects in modern environments” and adding “Another possibility is that our between-subjects experiment design with a sample size of 202 participants might have been inadequate to detect a small or medium effect of omission bias. A replication of the current experiment with a larger sample size might help to clarify this possibility”(Lines 500-505).

The best fitting model for average severity ratings is the null model, so the best-fitting model does not include any of the predictors of interest. For proportion of correct recall, the best fitting model did include our predictors of interest (Condition and Vaccination attitudes) and their interaction together with Reaction Time. However, the model fit was similar to the control model (with Reaction Time as unique predictor). Consequently, we do not think it is necessary to report this.

Gender of participants

I found the (quite interesting!) rationale for testing only female participants in the supplementary material, but I think it’s worth mentioning briefly in the main text because many readers will wonder about it.

We have now included the sentences about our selection of only female participants in the main text (Lines 250-258)

Attachments
Attachment
Submitted filename: Response to Reviewers.docx
Decision Letter - Catharine Penelope Cross, Editor

NO EVIDENCE THAT OMISSION AND CONFIRMATION BIASES AFFECT THE PERCEPTION AND RECALL OF VACCINE-RELATED INFORMATION

PONE-D-19-27807R1

Dear Dr. Jimenez,

We are pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it complies with all outstanding technical requirements.

Within one week, you will receive an e-mail containing information on the amendments required prior to publication. When all required modifications have been addressed, you will receive a formal acceptance letter and your manuscript will proceed to our production department and be scheduled for publication.

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With kind regards,

Catharine Penelope Cross

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Dear Dr Jimenez

I am delighted to see such a clear and thorough response to the reviewer comments. Many thanks to you and your co-authors for making the changes and explaining the rationale for these changes (or absence of changes) in such an exemplary way.

Reviewers' comments:

Formally Accepted
Acceptance Letter - Catharine Penelope Cross, Editor

PONE-D-19-27807R1

No Evidence that Omission and Confirmation Biases Affect the Perception and Recall of Vaccine-related Information

Dear Dr. Jiménez:

I am pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please notify them about your upcoming paper at this point, to enable them to help maximize its impact. If they will be preparing press materials for this manuscript, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

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With kind regards,

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on behalf of

Dr. Catharine Penelope Cross

Academic Editor

PLOS ONE

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