This is quite a remarkable study from a 1985 edition of the International Journal of Neuroscience that investigated whether the apparent greater use of mental imagery during masturbation by men than women was due to differences in hemispheric specialisation.
To test whether this might be to do with brain organisation, rather than gender itself, the researchers tested the idea by asking about imagery during masturbation in right-handed males, who typically show strong hemispheric specialisation, and left-handed men, who typically show less specialisation.
Unfortunately, I don’t have access to the full paper and have no idea whether the claim that women typically report less imagery and fantasy is still thought reliable, as these sorts of findings are notoriously influenced by how the question is asked.
However, the study seemed to find partial support for it’s own hypothesis at least.
Sex and handedness differences in the use of autoerotic fantasy and imagery: a proposed explanation.
Int J Neurosci. 1985 May;26(3-4):259-68.
Previous research has described a greater use of fantasy and imagery during masturbation by men, than women. This study suggests that this gender disparity results from the increased frequency of bilateral speech representation found in the female brain. Support for this theory was obtained by comparing the use of autoerotic fantasy and imagery in another group distinguished by their degree of cerebral lateralization: dextral vs. sinistral males. The prediction that masturbatory fantasy and imagery would be more common in the more lateralized dextral males was partially confirmed in this study.
I gave up looking for a suggestive yet tasteful image than combined the concepts of sex and hemispheric specialisation, so I’ve illustrated this post with picture of a flower instead.
As an aside, brain anatomy has a few rude jokes thrown in. For example, the mammillary bodies are two small round areas that are part of the limbic system. Their name comes from the fact that the look like breasts.
I was told by a neuroanatomy lecturer that one of the reasons given for why women shouldn’t study medicine in the 1900s was because they’d be offended by the blue humour.
Link to PubMed entry for hemispheric fantasy study.