It's more brilliant than you think—now the Microsoft employees who came up with this idea can get MacBooks without getting their boss's signature! In theory, anyway.

Well... there's the beachfront property market.

See also: Slashdot and unicode support.

Hey, definitely. I'm all for this sort of interest piece; I've done some truly worthless statistical analyses purely for the geek value. But it shouldn't be mislabeled, much less sitting on Arxiv. I guess maybe this happened because the lead author is a physicist? Assume a spherical cow, etc.

Exactly. The results of this study could not be more bullshit. It's the kind of "why would you even bother doing that" study that should make people double over laughing.

We'd deal with them the same way we dealt with Denmark. Simple.

As another commenter said already, Canada went through nuclear disarmament in 1984. (The US wasn't pleased.) "Develop" is definitely the wrong word.

Alas, they also noted differences in brain activation when the subjects were shorn pornographic imagery, so that joke doesn't quite work, unless they were secretly controlling their muscles for the elbow and wrist in the MRI tube. But we can pretend it does!

The study asserts that there is; alcoholism and other drug addictions are already associated with striatum differences.

That's unfortunately quite a tall order for the Slashdot community. Now, if you'd wish they'd ramble tiresomely about tiny mosquito-decapitating robot overlords running out of control, you might not go home quite so disappointed.

Just for your convenience, then, here are all the statistics from the paper:

• Research in the United States has shown that 66% of men and 41% of women consume pornography on a monthly basis.3 An estimated 50% of all Internet traffic is related to sex.4
• Sixty-four healthy male participants (mean [SD] age, 28.9 [6.62] years, range 21-45 years) were recruited.
• Because the distribution of the reported PHs [hours of pornography use per week] was skewed and not normally distributed (Kolmogorov-Smirnov, Z=1.54; P<.05), we transformed the variable by means of square root (Kolmogorov-Smirnov, Z=0.77; P=.59).
• The overall Internet Sex Screening Test score was positively correlated with the reported PHs (r64=0.389, P<.01). On the Sexual Addiction Screening Test, participants scored 1.35 on average (SD, 2.03). A positive correlation was observed between PHs and Alcohol Use Disorder Identification Test score (r64=0.250, P<.05) and Beck Depression Inventory score (r64=0.295, P<.05).

And just because it's so important to the science, the rest of the results:

When correlating PHs (square root) with GM segmentations, we found a significant negative association in the right striatum, namely caudate nucleus (based on the automated anatomical labeling atlas34; peak voxel: x=11, y=5, z=3; P<.001; corrected for multiple comparisons) (Figure 1A). When we used a lower threshold of P<.005, an additional cluster in the left caudate reached significance (x=6, y=0, z=6), showing that the effect is not clearly lateralized. We refer to the cluster as the striatum; however, for the subsequent discussion, it is noteworthy that the cluster overlaps with a reward processing literature-based probabilistic region of interest of the ventral striatum, created by means of in-house software35 (predominantly monetary-incentive delay task, see eAppendix in Supplement for details).

As for alternative hypotheses, the only one they present is "Individuals with lower striatum volume may need more external stimulation to experience pleasure and might therefore experience pornography consumption as more rewarding, which may in turn lead to higher PHs."

That may call into question cause, but not consequence; if pursuing a drug addiction causes behavioural changes (which alcoholism certainly does, even when sober) then it is not unreasonable to assume some alteration in activity or structure of the striatum comes as a result of this. The paper cites previous work on the topic, saying that alcoholism (and drug addiction in general) is indeed correlated with changes in the striatum, so I wouldn't really question that part of it too vigorously. My complaint is basically that they seem to be violating a triangle inequality: the brain change is tightly correlated with two addictive behaviours in the sample, but they're only weakly correlated with each other. It sounds to me like porn is correlated with novel changes in the same region.

Now that I've had a chance to sit down and read through both the study and a few other things... you're correct, but it's not completely clear-cut, at least in my opinion, that the changes under consideration actually relate to reward-seeking, addict-like behaviour and aren't simply, say, a lack of sexual development due to being single.

They found a variety of different features in their test subjects (actual anatomical differences, differences in activity level within the caudate, differences in interconnectedness between pudamen and caudate...) and saw these were strongly correlated with level of pornography use, on the basis of addiction. However, there were some people in the study who used alcohol in a mildly problematic way. They showed only a r = ~0.25 (weak positive correlation) with porn usage. That strikes me as pretty inconsistent—if these are pathways strongly implicated in addictive behaviour, why didn't the drunks line up more neatly with their data? They don't mention alcoholism again in the discussion, except to draw parallels between porn usage and various forms of drug usage, and to suggest psychiatrists should ask about porn usage.

Don't assume it means anything—the striatum's primary function is coordinating motor control. If there is a meaningful causal link and this study is not just a p-value fishing expedition, it is so convoluted as to be incomprehensible.