PONE-D-21-17431

Cleaner wrasse Labroides dimidiatus perform above chance in a "Matching-to-sample" experiment

PLOS ONE

Dear Dr. Aellen,

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.

So far I have had one independent expert on animal behaviour review the manuscript, and I have also carefully read the work. I agree with R1 that the work is potentially of interest to publish, but clarity of explanations and writing can be improved a lot (see reveiwer report). In particular, I agree with R1 that readers need a more complete explanation of MTS (matching to sample)for which you use simultaneous presentation, and how delayed MTS (ie DMTS) experiments has been more frequently used in other animal species, at least in recent times. DMTS requires buth longer term memory formation of rule, and working memory (WM) of samples in a particular instance. The simultaneous MTS thus is not directlly comparable to DMTS; at least you need to clearly explain differences for readers and how such differences influence your experimental interpretation(s).

I also found the line "Fish were fed ad libitum for five minutes 20 minutes prior to the start of the experiment." confusing as to what this meant.........please use a lot more care so a general readership can fully understand your paper. I also was confused by s3 Figure which I cant see mentioned in main manuscript. Can you please take much more care in paper presentation and message? I have allowed time for a major revision to enable this. If you can do a good job I will then ask R1 and another expert to review the revised paper.

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We look forward to receiving your revised manuscript.

Kind regards,

Adrian G Dyer, Ph.D.

Academic Editor

PLOS ONE

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 [The study was supported by the Swiss National Science Foundation (grant numbers 31003A_153067 and 310030B_173334/1) to R.B. 

NO]. 

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[We are grateful to the Gump research station in Moorea (French Polynesia) for letting us work in their station. We are particularly thankful to the directors and the staff for their unconditional help and great friendship. We thank Léonore Bonin for fish capturing. We acknowledge Dr. Christèle Borgeaud for English corrections and valuable comments. We thank Radu Alexandru Slobodeanu for statistical help and support. The study was supported by the Swiss National Science Foundation (grant numbers 31003A_153067 and 310030B_173334/1) to R.B.]

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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

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

Reviewer #1: I Don't Know

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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: 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: No

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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: In this study, the authors tested the ability of cleaner fish to succeed in a simultaneous matching-to-sample task. Such task is classically used to test for rule learning based on a ‘same’ abstract relational concept. This cognitive ability has been established in many animal species from mammals to insects. However, while some fish species appeared able to master this task (zebrafish and goldfish), others were not (e.g. archerfish). The current study thus proposes to further explore fish concept learning capacities by testing an additional species. This question is scientifically valid and of interest as I consider that the comparative cognition field certainly gains from more model species to be tested for key cognitive tasks. The results demonstrate great individual variability but with success of a few individuals. These results support the existence of an ability for solving matching-to-sample task in this species in particular as the procedure chosen is not classic and may have had detrimental effect on performance. Indeed, usually, the sample is not longer present when the subject has to make a choice between a stimulus identical to the sample and an alternative stimulus. In addition, only a limited number of samples are used in standard procedures at least during the acquisition phase while in the current study, each trial presented a novel stimulus. These key differences may have induced attentional bias and noise which prevented most subjects to extract the common rule between trials. Proposing alternative procedures is of high interest to better understand the underlying processes but I regret that the authors did not test in parallel the classical procedure for comparison. With the current data, it is indeed impossible to compare the cleaner fish performances with those of other species.

Other comments:

Introduction: The introduction needs quite a substantial editing. Some sentences are difficult to read, some others are incorrect or imprecise. I recommend the authors to invest more effort in drafting the introduction in a novel version of the manuscript.

A few examples:

l. 35 : do you mean a shaping procedure ? It is not clear what you mean by operant conditioning. Your description does not allow to understand what is the procedure to study the ability of animals to learn abstract concepts. Please revise the lines 34-37

l. 46 : I do not understand this sentence. ‘concepts are represented by the relation of abstract rules to novel stimuli’ ??

l. 49-53 : Difficult to follow, please revise for improved clarity

l.57 : The reference 27 seems fully out of context here. Could you please provide references of studies using simultaneous MTS to test for same/difference concept learning ?

l. 58: Incorrect references as they used a DMTS procedure and not a simultaneous MTS

…

Methods

l. 164 : Why did you feed the fish ab libitum before the experiment. This should induce a lack of motivation for the food reward.

l. 165 : Why did you let the food plate in place for 2 hours ?

I suggest to provide a video as supporting information to help the reader to better picture the whole procedure.

Discussion

l.228 : There is at least one study, the one in pigeons which is described a few sentences later (ref 12)

Bibliography : please check the references formatting as not consistent between references and does not follow the journal guidelines.

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Reviewer #1: No

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Cleaner wrasse Labroides dimidiatus perform above chance in a "Matching-to-sample" experiment

PONE-D-21-17431R1

Dear Dr. Aellen,

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

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Adrian G Dyer, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Appologies for slow response; 2021 is a difficult year for obtaining reviewers as many people are disrupted. The manuscript has now been reviewed twice by a world expert on the topic, and I have also carefully read the manuscript versions. As the expert reviewer now recommends acceptance; I am recommending acceptance of the manuscript.

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

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2. 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

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

Reviewer #1: Yes

**********

4. 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

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5. 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

**********

6. 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: (No Response)

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No