Acquisition and long-term memory of object names in a sample of Gifted Word Learner dogs

Dogs with a vocabulary of object names are rare and are considered uniquely gifted. In a few cases, these Gifted Word Learner (GWL) dogs have presented cognitive skills that are functionally similar to those of human infants. However, the acquisition rate of new object names and the ability of GWL dogs to form long-term memories of those is unknown. In this study, we examine the ability of six GWL dogs to acquire the names of new objects in a short period and to retain those in their long-term memory without post-acquisition exposures. In Experiments 1 and 2, the dogs were tested on their ability to learn, during social interactions with their owners, the names of 6 and 12 new toys respectively, in one week. In Experiments 3 and 4, the dogs' memory of these objects was tested after one and two months. GWL dogs typically learned the names of the new objects and remembered those. We suggest that dogs with knowledge of object names could be a powerful model for studying mental mechanisms related to word acquisition in a non-human species.

for anything other than an efficient associative mechanism… That is all that THEY tested. They cannot argue that their dogs would perform as well as others trained and tested in different paradigms. The authors are correct that the POSSIBILITY exists, but their claims for THEIR data are way too strong. L. 237: Acquiring associations that MAY or MAY NOT be object labels.
As I noted before: Not only are these dogs gifted, but they are all Border collies-dogs specifically BRED to learn quickly and to understand vocal commands given by humans…and even then, not all their subjects do well. Note that collies are no longer bred specifically for herding, but likely for physical standards of "beauty", so that the genetics no longer hold as strongly, which may be why so few dogs succeed.
I repeat my earlier criticism, that although I DO find the behavior of some of these dogs impressive, I do not agree that their behavior is all that similar to that of children who are learning labels nor that dogs (in genera!?!--remember only a few Border collies succeed in any kind of label learning at all) can be a model for studying mechanisms involved in human word acquisition. The authors should stick to their truly impressive data (which are impressive!) rather than make additional claims of parallels with human acquisition.
They have backed down a bit and said that more work is needed, but they haven't backed down enough, simply because they do not have the data beyond one dog, Whiskey, to make any such claims-no other dog of theirs has been appropriately tested.
In References: Why are some titles of journal articles capitalized whereas other are not?

Review form: Reviewer 2
Is the manuscript scientifically sound in its present form? Yes

Are the interpretations and conclusions justified by the results? Yes
Is the language acceptable? Yes

Recommendation?
Accept with minor revision (please list in comments)

Comments to the Author(s)
In this paper, the authors recruited 6 dogs who had previously demonstrated the ability to associate toys with specific names. They then tested their ability to learn new associations of 6 + 12 objects over a short period (1 week), and whether the dogs could retain those associations 1 and 2 months later without any practice in the meantime. I thought the premise was interesting, the design was well-executed, and the conclusions were warranted. I did still have a few questions about the specifics (e.g. subject criteria, methodology) which are addressed below in my line-by-line feedback.
Title: I wonder if would be better to say 'acquisition' as opposed to 'learning rate' since your question is broader and categorical (i.e. yes/no did the dogs learn the words in a set amount of time) vs. the specifics that 'learning rate' might call to mind (i.e. how many exposures are needed/learning curves/etc.). Also, rather than 'selected' dogs, maybe 'word-knowledgeable' dogs (or some descriptor that defines how they were selected). Line 15. Might be useful to clarify here that they are retaining in their memory 'without further practice post-acquisition' or something like that? Lines 59-64. This sentence is hard to parse and parts are redundant. I think it would be easier to understand if rephrased slightly and broken up into 2 sentences. Maybe something like: "In infants, the ability to rapidly learn new words is thought to mark a shift in their thinking, whereby they now realize that words represent objects [15]. Thus, evidence for comparable rapid learning of object names in dogs, combined with previous evidence showing that dogs with vocabulary knowledge relate labels to categories of items, instead of only associating one word to one object [16], may support the idea that dogs, similar to human children, can learn that words represent items [12]." Subject criteria -how was their knowledge of over 26 object names verified? E.g. owner report or actually tested by an independent party? Were there nominated dogs who were deemed to not actually meet the criteria? I think it would be helpful to either explain in more detail and/or provide a link to the website (geniusdogchallenge.com), which I found by googling the Genius Dog Challenge social media campaign that you first mention in the experimental setup section directly below. The 'How to Apply' section of the website (assuming that is the criteria the 6 current dogs were held to?) was useful in ascertaining how dogs were deemed to meet the criteria. Line 107-111: obviously sample size is such that we can't draw any firm conclusions, but would be interesting to know which subjects specifically were trained for an avg of 1.5 h and 2.5-5.5 h, respectively Lines 144-145: why did the owner remove the requested toy if the dog brought the incorrect one? To make it the same # and ratio of test/control items between dogs? Please explain rationale. And what happened with the incorrectly retrieved toy? Was it replaced, or also removed? Lines 173-176: what was the rationale for replacing the toys after 3 and 9 trials (as opposed to after every trial)? Why did the # of trials between replacement differ between experiments? Line 190: It would be helpful to present results of experiment 3 and experiment 4 as you do the first 2 experiments… i.e. when you say XX dogs retrieved all toys, remind the reader of the total number of all toys. So, "In Experiment 3, five dogs successfully retrieved all 6 toys" and "In Experiment 4, three dogs successfully retrieved all 6 toys" Line 191: how many toys did the dog who didn't perform above chance successfully retrieve? Line 253: ah great -here is the link to the website! Although this also clarifies that the website was used as a recruitment tool AFTER the recruitment of the 6 dogs in the current study (presumably for future studies)… so I think still useful to add more detail in the methods re: recruitment, at the detail level of the 'how to apply' page of the website Line 266: consider rephrasing to "The similarities in word learning rate (or acquisition??) and retention capacity between infants and 'word-knowledgeable' dogs further suggests that…" Decision letter (RSOS-210976.R0) We hope you are keeping well at this difficult and unusual time. We continue to value your support of the journal in these challenging circumstances. If Royal Society Open Science can assist you at all, please don't hesitate to let us know at the email address below.

Dear Ms Dror
On behalf of the Editors, we are pleased to inform you that your Manuscript RSOS-210976 "Learning rate and long-term memory of object names in a sample of selected dogs " has been accepted for publication in Royal Society Open Science subject to minor revision in accordance with the referees' reports. Please find the referees' comments along with any feedback from the Editors below my signature.
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Thank you for submitting your manuscript to Royal Society Open Science and we look forward to receiving your revision. If you have any questions at all, please do not hesitate to get in touch. This is a fascinating piece of work and will be of much interest. The two reviewers would like to see some revisions made and so would we.
The work as dog qua dog is good enough to stand alone without making claims that the dog is a good model for learning about the development of language in children. This is nonsensicalthere are a super abundance of children from whom we can gather phenotypic and genetic data that directly bear on human language development -we don't need dogs for that -if you have a particular idea in mind for why the dog is a good model or what we could learn from dogs that we cannot learn from human children and their adult relatives, then please say it.
What is striking and interesting here is the evidence of variation among individuals and of capacity. That this work was done under the restrictions of the pandemic is especially praiseworthy.
I would consider cutting the references to cross-species comparisons, but at the least, please do listen to Reviewer 1 who proposes that the ms still in places goes beyond its evidence. It doesn't' need to -the work is great as it is. Reviewer 2 has asked some key questions. Answering those will strengthen the ms.
We hope you will revise this after a careful reading of the Reviewer comments. It will be a splendid paper.
Reviewer comments to Author: Reviewer: 1 Comments to the Author(s) Dror and colleagues have revised their intriguing paper on the capacities of dogs to learn human labels for objects and to retain these labels for several months. I still have a few comments on the paper as the authors have not quite addressed all my concerns.
L. 19: I still object to the comparison between the dogs and young children. As I noted before, even if children have a very small vocabulary before their 'spurt', the labels are not restricted to one particular object (a "ball" will be used to refer to a number of different balls, and even sometimes the label is over-or under-extended). To argue that dogs are good models for other nonhumans, however, DOES make sense.
L. 34: Here the authors have shifted from early vocabulary acquisition to children well beyond the beginning of the vocabulary spurt…and then shift back to 2 yr olds…the children here are in very different stages and comparisons that are being made are confusing and conflate many issues.
L. 53-55: I would again argue that all these dogs learned was a brief association of sound and object; to call this behavior the learning of names is quite a stretch.
L. 59-63: This sentence is quite complex and difficult to parse…please edit. L. 63: I agree that one dog seems to understand something about categories, which suggests that such learning is possible…but the authors cannot make such claims for the other subjects in the other studies and later for all their subjects. L. 110: 5.5 hrs/day is intensive training! Which dog was that? Did that dog do better than some of the others? Would be an important bit of information! And why are descriptions of Experiment 2 placed in the paragraph devoted to Experiment 1? L. 118: How did the experimenters guarantee that the toys were stored away and that the owners did not review things with their dogs? Promises to do so are nice, but people often want their dogs to shine, so…. L. 128: There's a certain amount of 'exclusion' occurring here-dog knows it has fetched X already, so maybe knows to ignore X at least for awhile? Why not put in a mix of fetched and some other old toys, or maybe a brand new, unnamed toy? L. 163: So here the owner showed the dog the correct toy? Wouldn't that act as a refresher trial? L. 175ff: To be truly conservative, the chance level should be 1/6 for the first set and 1/12 for the second, assuming that the dog would ignore its old toys and just concentrate on the new ones… L. 209: In reality, only SOME OF the dogs could perform the task….the authors cannot make a broad generalization.
L. 222ff: Given that the labels are connected to a SINGLE object, rather than a class (e.g., "balls", which is what Pilley and Reid tried to test) for the dogs in THIS study, the authors cannot argue for anything other than an efficient associative mechanism… That is all that THEY tested. They cannot argue that their dogs would perform as well as others trained and tested in different paradigms. The authors are correct that the POSSIBILITY exists, but their claims for THEIR data are way too strong.
L. 237: Acquiring associations that MAY or MAY NOT be object labels.
As I noted before: Not only are these dogs gifted, but they are all Border collies-dogs specifically BRED to learn quickly and to understand vocal commands given by humans…and even then, not all their subjects do well. Note that collies are no longer bred specifically for herding, but likely for physical standards of "beauty", so that the genetics no longer hold as strongly, which may be why so few dogs succeed.
I repeat my earlier criticism, that although I DO find the behavior of some of these dogs impressive, I do not agree that their behavior is all that similar to that of children who are learning labels nor that dogs (in genera!?!--remember only a few Border collies succeed in any kind of label learning at all) can be a model for studying mechanisms involved in human word acquisition. The authors should stick to their truly impressive data (which are impressive!) rather than make additional claims of parallels with human acquisition.
They have backed down a bit and said that more work is needed, but they haven't backed down enough, simply because they do not have the data beyond one dog, Whiskey, to make any such claims-no other dog of theirs has been appropriately tested.
In References: Why are some titles of journal articles capitalized whereas other are not?
Reviewer: 2 Comments to the Author(s) In this paper, the authors recruited 6 dogs who had previously demonstrated the ability to associate toys with specific names. They then tested their ability to learn new associations of 6 + 12 objects over a short period (1 week), and whether the dogs could retain those associations 1 and 2 months later without any practice in the meantime. I thought the premise was interesting, the design was well-executed, and the conclusions were warranted. I did still have a few questions about the specifics (e.g. subject criteria, methodology) which are addressed below in my line-by-line feedback.
Title: I wonder if would be better to say 'acquisition' as opposed to 'learning rate' since your question is broader and categorical (i.e. yes/no did the dogs learn the words in a set amount of time) vs. the specifics that 'learning rate' might call to mind (i.e. how many exposures are needed/learning curves/etc.). Also, rather than 'selected' dogs, maybe 'word-knowledgeable' dogs (or some descriptor that defines how they were selected). Line 15. Might be useful to clarify here that they are retaining in their memory 'without further practice post-acquisition' or something like that? Lines 59-64. This sentence is hard to parse and parts are redundant. I think it would be easier to understand if rephrased slightly and broken up into 2 sentences. Maybe something like: "In infants, the ability to rapidly learn new words is thought to mark a shift in their thinking, whereby they now realize that words represent objects [15]. Thus, evidence for comparable rapid learning of object names in dogs, combined with previous evidence showing that dogs with vocabulary knowledge relate labels to categories of items, instead of only associating one word to one object [16], may support the idea that dogs, similar to human children, can learn that words represent items [12]." Subject criteria -how was their knowledge of over 26 object names verified? E.g. owner report or actually tested by an independent party? Were there nominated dogs who were deemed to not actually meet the criteria? I think it would be helpful to either explain in more detail and/or provide a link to the website (geniusdogchallenge.com), which I found by googling the Genius Dog Challenge social media campaign that you first mention in the experimental setup section directly below. The 'How to Apply' section of the website (assuming that is the criteria the 6 current dogs were held to?) was useful in ascertaining how dogs were deemed to meet the criteria. Line 107-111: obviously sample size is such that we can't draw any firm conclusions, but would be interesting to know which subjects specifically were trained for an avg of 1.5 h and 2.5-5.5 h, respectively Lines 144-145: why did the owner remove the requested toy if the dog brought the incorrect one? To make it the same # and ratio of test/control items between dogs? Please explain rationale. And what happened with the incorrectly retrieved toy? Was it replaced, or also removed? Lines 173-176: what was the rationale for replacing the toys after 3 and 9 trials (as opposed to after every trial)? Why did the # of trials between replacement differ between experiments? Line 190: It would be helpful to present results of experiment 3 and experiment 4 as you do the first 2 experiments… i.e. when you say XX dogs retrieved all toys, remind the reader of the total number of all toys. So, "In Experiment 3, five dogs successfully retrieved all 6 toys" and "In Experiment 4, three dogs successfully retrieved all 6 toys" Line 191: how many toys did the dog who didn't perform above chance successfully retrieve? Line 253: ah great -here is the link to the website! Although this also clarifies that the website was used as a recruitment tool AFTER the recruitment of the 6 dogs in the current study (presumably for future studies)… so I think still useful to add more detail in the methods re: recruitment, at the detail level of the 'how to apply' page of the website Line 266: consider rephrasing to "The similarities in word learning rate (or acquisition??) and retention capacity between infants and 'word-knowledgeable' dogs further suggests that…" ===PREPARING YOUR MANUSCRIPT=== Your revised paper should include the changes requested by the referees and Editors of your manuscript. You should provide two versions of this manuscript and both versions must be provided in an editable format: one version identifying all the changes that have been made (for instance, in coloured highlight, in bold text, or tracked changes); a 'clean' version of the new manuscript that incorporates the changes made, but does not highlight them. This version will be used for typesetting.
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See Appendix A.
Decision letter (RSOS-210976.R1) We hope you are keeping well at this difficult and unusual time. We continue to value your support of the journal in these challenging circumstances. If Royal Society Open Science can assist you at all, please don't hesitate to let us know at the email address below.

Dear Ms Dror,
It is a pleasure to accept your manuscript entitled "Acquisition and long-term memory of object names in a sample of Gifted Word Learner dogs " in its current form for publication in Royal Society Open Science. The comments of the reviewer(s) who reviewed your manuscript are included at the foot of this letter.
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The work as dog qua dog is good enough to stand alone without making claims that the dog is a good model for learning about the development of language in children. This is nonsensical -there are a super abundance of children from whom we can gather phenotypic and genetic data that directly bear on human language development -we don't need dogs for that -if you have a particular idea in mind for why the dog is a good model or what we could learn from dogs that we cannot learn from human children and their adult relatives, then please say it.
Authors answer: We thank the editor for this comment. We would like to clarify that we do not suggest dogs as a model for developmental aspects (see lines 256-260) but rather for evolutionary, cognitive, and comparative aspects of cognition that are related to language (see the discussion about domain-general learning mechanisms described in lines 267-270). The dog has already been recognized as a model for social cognition, examined in behavioral (Topál et al., 2009) and neuroimaging (Bunford et al., 2017) studies. Here we suggest that GWL dogs expand this possibility to aspects of cognition thought to be related to language in humans.
What is striking and interesting here is the evidence of variation among individuals and of capacity. That this work was done under the restrictions of the pandemic is especially praiseworthy.
I would consider cutting the references to cross-species comparisons, but at the least, please do listen to Reviewer 1 who proposes that the ms still in places goes beyond its evidence. It doesn't' need to -the work is great as it is. Reviewer 2 has asked some key questions. Answering those will strengthen the ms.
We hope you will revise this after a careful reading of the Reviewer comments. It will be a splendid paper. I repeat my earlier criticism, that although I DO find the behavior of some of these dogs impressive, I do not agree that their behavior is all that similar to that of children who are learning labels nor that dogs (in genera!?!--remember only a few Border collies succeed in any kind of label learning at all) can be a model for studying mechanisms involved in human word acquisition. The authors should stick to their truly impressive data (which are impressive!) rather than make additional claims of parallels with human acquisition.
They have backed down a bit and said that more work is needed, but they haven't backed down enough, simply because they do not have the data beyond one dog, Whiskey, to make any such claims-no other dog of theirs has been appropriately tested.
Authors answer: we thank the reviewer for giving us a second opportunity to clarify our claims. As now explained in L. 263-266 and L. 272-274 we do not claim that the cognitive mechanisms are similar but rather that there is much to be learned from comparative research.
In References: Why are some titles of journal articles capitalized whereas other are not?
Authors answer: we apologize for the inconsistency. It has now been corrected.

Reviewer: 2
Comments to the Author(s) In this paper, the authors recruited 6 dogs who had previously demonstrated the ability to associate toys with specific names. They then tested their ability to learn new associations of 6 + 12 objects over a short period (1 week), and whether the dogs could retain those associations 1 and 2 months later without any practice in the meantime. I thought the premise was interesting, the design was well-executed, and the conclusions were warranted. I did still have a few questions about the specifics (e.g., subject criteria, methodology) which are addressed below in my line-by-line feedback.