It looks to me like your link is a 1995 study, and my link described a 2000 or 2001 study, which I’m having trouble finding. I think it might be this one but I’m not seeing the 3.1% value anywhere. The study I linked has slightly lowered my credence in the 3.1% number, but I can’t tell if the numbers it’s reporting are per-act numbers or not. (I’m not an expert in this field and have been trusting summaries from science journalists; I’m not sure if I’m interpreting the actual papers correctly or not.) It looks like this study might have said “at their least fertile, there’s less than a 5% per-act chance of copulation, which is lower than we thought it was” and that got interpreted as “in general, there’s less than a 5% per-act chance of copulation.”
I hope Gottschall and company know what they’re doing, and expect the 3.1% number comes from another study. It might be profitable to email one of the professors in question and ask for where that number came from, because it’s being slippery.
Edit: I would like to criticize Todd Akin for making my truth-seeking less convenient by really messing up the signal-to-noise ratio regarding this matter.
It looks to me like your link is a 1995 study, and my link described a 2000 or 2001 study, which I’m having trouble finding. I think it might be this one but I’m not seeing the 3.1% value anywhere. The study I linked has slightly lowered my credence in the 3.1% number, but I can’t tell if the numbers it’s reporting are per-act numbers or not. (I’m not an expert in this field and have been trusting summaries from science journalists; I’m not sure if I’m interpreting the actual papers correctly or not.) It looks like this study might have said “at their least fertile, there’s less than a 5% per-act chance of copulation, which is lower than we thought it was” and that got interpreted as “in general, there’s less than a 5% per-act chance of copulation.”
I hope Gottschall and company know what they’re doing, and expect the 3.1% number comes from another study. It might be profitable to email one of the professors in question and ask for where that number came from, because it’s being slippery.
Sorry, for deleting my post. I linked to the wrong study (as you pointed out) and wanted no replies until I revised my post.
Also, this is the 2001 study:
http://www.ncbi.nlm.nih.gov/pubmed/11376648
Edit: I would like to criticize Todd Akin for making my truth-seeking less convenient by really messing up the signal-to-noise ratio regarding this matter.