On 2014 Nov 27, Jürgen Hänggi commented:

Dear community

a study recently published by our group questioned the sex effects reported here. We also conducted two very interesting between sex comparisons in order to tract down whether increased interhemispheric connectivity in women and increased intrahemispheric connectivity in men might be confounded by differences in brain size. One comparison is called "extreme group comparison" and compared small female brains with large male brains. This comparison revealed that the effect under question became much stronger because the difference in brain size between these two groups became stronger as well. The other comparison has been called "control group comparison" and used men with small brains who were compared with women with large brains. This comparison shows that the "apparent sex effect" disappeared because these two groups did not differ in brain size any longer. Although both comparisons involved women and men, the first comparison showed a positive result, whereas the second comparison provided a negative finding. These comparisons alone provide strong evidence that clearly contradicts "increased interhemispheric connectivity in women and increased intrahemispheric connectivity in men". The hypothesis of neuronal interconnectivity as a function of brain size represents a general and fundamental organization principle of the human connectome that is sex-independent and that might be applied also to non-human animals as suggested by our cross-species comparison.

Our study can be found here

http://journal.frontiersin.org/Journal/10.3389/fnhum.2014.00915/full

Further discussion with respect to the effect size as well as comparisons of small, medium and large brain size groups and a network-based statistical analysis similar to the analysis conducted in the study under question can be found here

http://www.juergenhaenggi.ch/index.php?option=com_content&view=category&layout=blog&id=58&Itemid=136

A critical discussion of the problem of overpowered studies and its associated "trivial effects" can be found here

http://www.sciencedirect.com/science/article/pii/S1053811912003990

On 2014 Nov 01, Jürgen Hänggi commented:

None

On 2014 May 29, Gerard Ridgway commented:

This paper reports no effect sizes. An illustrative example based on converting from t and degrees of freedom to an estimate of Cohen's d can be found here: http://figshare.com/articles/Illustrative_effect_sizes_for_sex_differences/866802

On 2013 Dec 05, Allison Stelling commented:

This paper has generated quite a lot of commentary in the press. Here's a sampling of some of the coverage thus far, mostly from the discussion occurring on PubPeer at https://pubpeer.com/publications/3CFCCE950D22E7560E9B07C8B63979:

https://theconversation.com/are-men-better-wired-to-read-maps-or-is-it-a-tired-clich-21096

https://theconversation.com/new-insights-into-gendered-brain-wiring-or-a-perfect-case-study-in-neurosexism-21083

(These links are in Peer 0's post, please see: https://pubpeer.com/publications/3CFCCE950D22E7560E9B07C8B63979/comments/4381)

I personally don't buy fMRI in general to measure anything other than water nuclei in tissues. The physical correlates for "activity" seem murky at best and I tend to take any interpretation other than 'bulk tumor mass' with a grain of salt.

On 2013 Dec 05, Allison Stelling commented:

This paper has generated quite a lot of commentary in the press. Here's a sampling of some of the coverage thus far, mostly from the discussion occurring on PubPeer at https://pubpeer.com/publications/3CFCCE950D22E7560E9B07C8B63979:

https://theconversation.com/are-men-better-wired-to-read-maps-or-is-it-a-tired-clich-21096

https://theconversation.com/new-insights-into-gendered-brain-wiring-or-a-perfect-case-study-in-neurosexism-21083

(These links are in Peer 0's post, please see: https://pubpeer.com/publications/3CFCCE950D22E7560E9B07C8B63979/comments/4381)

I personally don't buy fMRI in general to measure anything other than water nuclei in tissues. The physical correlates for "activity" seem murky at best and I tend to take any interpretation other than 'bulk tumor mass' with a grain of salt.

On 2014 May 29, Gerard Ridgway commented:

This paper reports no effect sizes. An illustrative example based on converting from t and degrees of freedom to an estimate of Cohen's d can be found here: http://figshare.com/articles/Illustrative_effect_sizes_for_sex_differences/866802

On 2014 Nov 01, Jürgen Hänggi commented:

None

On 2014 Nov 27, Jürgen Hänggi commented:

Dear community

a study recently published by our group questioned the sex effects reported here. We also conducted two very interesting between sex comparisons in order to tract down whether increased interhemispheric connectivity in women and increased intrahemispheric connectivity in men might be confounded by differences in brain size. One comparison is called "extreme group comparison" and compared small female brains with large male brains. This comparison revealed that the effect under question became much stronger because the difference in brain size between these two groups became stronger as well. The other comparison has been called "control group comparison" and used men with small brains who were compared with women with large brains. This comparison shows that the "apparent sex effect" disappeared because these two groups did not differ in brain size any longer. Although both comparisons involved women and men, the first comparison showed a positive result, whereas the second comparison provided a negative finding. These comparisons alone provide strong evidence that clearly contradicts "increased interhemispheric connectivity in women and increased intrahemispheric connectivity in men". The hypothesis of neuronal interconnectivity as a function of brain size represents a general and fundamental organization principle of the human connectome that is sex-independent and that might be applied also to non-human animals as suggested by our cross-species comparison.

Our study can be found here

http://journal.frontiersin.org/Journal/10.3389/fnhum.2014.00915/full

Further discussion with respect to the effect size as well as comparisons of small, medium and large brain size groups and a network-based statistical analysis similar to the analysis conducted in the study under question can be found here

http://www.juergenhaenggi.ch/index.php?option=com_content&view=category&layout=blog&id=58&Itemid=136

A critical discussion of the problem of overpowered studies and its associated "trivial effects" can be found here

http://www.sciencedirect.com/science/article/pii/S1053811912003990