Dear Claudia, You present an excellent example of how one can combine the often plethora of existing social behavior data with cognitive performance on an array of tests in a way that can shed light on current theory in need of such connections. The social intelligence hypothesis is desperately in need of such connections and your study provides a good step toward understanding its significance. It is extremely rare, yet very important, that all of the data (in this paper and the others for tasks A-D) are collected from the same individuals, therefore the small sample size is justified. Your conclusion that, while you do not provide causal evidence, but rather correlational evidence that cognitive performance relates to an increased involvement in social behaviors is a good distinction to make and will aid future work in developing experiments to test such causal relationships.
I have only minor comments: Line 56 - give an example of “striking cognitive features” so we have some context.
Line 62 - might want to also cite Jolly 1966 since she came up with the general idea of social intelligence first (http://www.sciencemag.org/content/153/3735/501.short)
Lines 80-81 - have a look at Healy & Rowe 2007 (http://rspb.royalsocietypublishing.org/content/274/1609/453.short) and Holekamp 2007 (http://www.sciencedirect.com/science/article/pii/S1364661306003263) to see if you want to cite these here as well. Particularly check the future directions at the end of the Holekamp paper.
Lines 81-83 - check out Thornton et al 2014 (http://beheco.oxfordjournals.org/content/early/2014/06/02/beheco.aru095.short) as I think you may want to cite it here.
Lines 83-84 - give an example.
Line 91 - there is no evidence yet that post-conflict affiliation is cognitively complex because alternative hypotheses have not been ruled out (i.e., bystanders initiating affiliation with victims occurs in species with large and small brain sizes and there is no direct evidence that it involves empathy). A stronger example here would be of the Eurasian jay males attending to their mate’s food preferences, recently published by Ostojic et al. 2013 (http://www.pnas.org/content/110/10/4123.short) and 2014 (http://rsbl.royalsocietypublishing.org/content/10/3/20140042.short).
Lines 92 and 93 - it is a bit confusing to say “recent” studies and in the next sentence “previously”. Clarification is needed.
Paragraph starting on line 116 - excellent interpretation. I would add more of this kind of language when explaining your results in the abstract because it will make more sense to the reader that hasn’t read your paper yet.
Line 136 - hatched, not born.
I’m a bit confused: do lines 137-140 refer to the time when the social behavior data were collected for this study and lines 140-143 refer to the time when the data were collected for the previously published papers on tasks A-D? If so, clarify.
Lines 148-149 - how does access to food depend on the number of cache sites? Clarify.
Lines 155-158 - move this part to earlier in this paragraph because it is distracting when placed after describing individuals going into testing rooms.
Line 175 - by separated, do you mean isolated?
Lines 178-184 - I’m not clear about which hand is which and which reward the term “reward” refers to. Distinguish between the exchange item and final reward by giving them different names that go with the different hands.
Line 201 - by “current study” do you mean Wascher et al (2012a) or the one in review? Clarify.
Line 228 - explain “pseudo-randomized order”.
Place the “Data and statistical analysis” section either before Tasks A-D or place “Behavioral protocol data” and “General testing procedure” after Tasks A-D to separate what you did in this study vs previously published research, otherwise I have a hard time keeping track of what goes with what.
Line 244 - explain what “this pattern” means.
Line 260 - how are you interpreting what approach means in the context of this study? One can approach another to engage in aggression or affiliation, but in and of itself, what is the significance of the approach? Explain this a bit more earlier.
Results: I have a hard time keeping track of what task goes with which task letter (A-D) so it would be good to mark which letter the task is in each sentence where you refer to a particular task. What does “respond stronger” mean in the inequity condition and heterospecific recognition experiments? Explain this with more description in the sentences in the results and discussion where you mention it. Also, remind the reader throughout the ms that tail and wing quivering are stress behaviors - I don’t think you directly make this link.
Line 357 - what are “association values”?
Line 360 - maybe add the Ostojic et al citations.
Lines 372-376 - does higher involvement in aggressive interactions also explain the “less impulsive” individuals’ increase in stress behaviors? If so, make the link between these two sentences clearer and explain what less impulsive means and that tail quivering is a stress behavior. Also define which exchange experiment you are referring to on line 375.
Lines 385-394 - are you saying that to measure optimality, one would need to do this study on relationships that are just forming rather than already established? If so, it isn’t entirely clear so make this part stronger.
Paragraph starting on line 401 - needs a topic sentence introducing the broader nature of this paragraph. Otherwise it is not clear how it relates to the rest of the discussion.
Figures: why did you choose to present just those two figures rather than all of the figures for initiating/receiving for each Task (A-D) with affiliative/aggressive/approach? I think all of the figures would be too much, but it isn’t clear why just these were chosen. You could make box plots with the initiated and received frequencies on the same graph but in different colors for comparison. Also, the figure legends say “y-axis”, but I think you mean “x-axis”.
In Figure 1, do the numbers on the x-axis go with each bird? If so, then I would make that clear. Also, “number of trials choosing the larger quantity” out of how many total trials?
One last note, the English needs to be cleaned up so if the copy editor doesn’t do this, have a native English speaker go through it for you.
All my best, Corina Logan