Does oxytocin enhance pro-social behaviors?
Oxytocin, individual differences, and trust game behavior: a registered large-scale replication
Recommendation: posted 19 April 2023, validated 21 April 2023
Espinosa, R. (2023) Does oxytocin enhance pro-social behaviors?. Peer Community in Registered Reports, . https://rr.peercommunityin.org/articles/rec?id=344
- Journal of Cognition
- Peer Community Journal
- Royal Society Open Science
- Swiss Psychology Open
The recommender in charge of the evaluation of the article and the reviewers declared that they have no conflict of interest (as defined in the code of conduct of PCI) with the authors or with the content of the article.
Evaluation round #1
DOI or URL of the report: https://osf.io/ea8uq?view_only=eb70b9bd53fd4b508fce42be1a33012c
Version of the report: 1
Author's Reply, 07 Apr 2023
Decision by Romain Espinosa, posted 13 Jan 2023, validated 15 Jan 2023
Thank you very much for submitting your manuscript to PCI-RR. I have now heard from two referees and I have also read your paper in detail. I believe your paper to be a very nice project and think you devoted a lot of effort in drafting your manuscript. Thank you for this.
I propose a round a revision to take into account the referees' comments (and possibly mine) to improve your manuscript.
Please let me know should anything be unclear.
• The Participants section mentions several elements that are mentioned in the design section. I would advice to put the design section before the participants section. For instance, you talk about Experimental Monetary Units (EMU) that you haven't introduced yet.
• Please define a procedure for potential floor or ceiling effects. I think that the very purpose of RR is to specify in advance what you plan to do. So, we should avoid as much as possible to leave it to ex-post decisions. (Page 18)
• I do not understand why you do not want to correct for multiple comparisons for your registered analyses. By definition, correcting for multiple hypothesis testing requires to know how many tests you will run. It is only possible with registered hypotheses (as we do not know what exploratory analyses you will do and how much of it you will report). You say in the design table that you do not need to correct because "no related analyses are conducted using this variable". Well, you look at the same dependent variable in three hypotheses (H1, H2, H3), with the same dataset. In my view, these hypotheses are part of the same family of hypotheses (the OXT has an effect), which would justify correction.
• As a side note: I think that you can use a linear model to analyze the investment decision (eventually a Tobit model in case you fear ceiling or floor effect) because the investment decision is a number of tokens. I do not see here why you would need a non-linear model.
• Page 21: You say "In case the effect of OXT on investments falls within the range ..." You talk about the confidence interval in the design table, which is clearer than this section. I would suggest to complement it.
• Why setting alpha=0.02 in the power analysis?
• Power analysis is made on H1 only. The main issue is that heterogeneity analysis (which is the case here for H2 and H3) requires more observations to maintain a sufficiently high statistical power. It would be nice to compute the expected statistical power of hypotheses 2 and 3.
• Design Table: I fear that the interpretation is a bit too strong for the first line. If you fail at rejecting H1, does it really mean that it contradicts the theory or does it mean instead that you fail at finding supporting evidence for the theory?
• Last, an important issue for me is the clustering of standard errors. Indeed: participants in your experiment spend some time discussing in small groups. This discussion session inevitably generates dependence between observations within the same session. In this case, we would usually cluster the standard errors at the session level. Note that clustering will drastically reduce your degree of freedom, but it seems the correct way to proceed.
• I agree with the anonymous referee who suggests to put the code of the power analysis online or in the manuscript.