Posts Tagged ‘neuroscience’

More on Brain Scans – Can They Tell Whether You’ll Get Off Lightly?

Tuesday, April 3rd, 2012

With a hat tip to our Uncle Ralph, here’s a link to yet another fMRI study bearing on criminal law. Makiko Yamada and colleagues have published in Nature Communications their study “Neural Circuits in the Brain that are Activated when Mitigating Criminal Sentences.”

The researchers asked people to review the facts underlying 32 hypothetical murder convictions. Half of them were designed to elicit sympathy for the convicted murderer, the other half to elicit no sympathy. The test subjects were told that each murderer had been given a 20-year sentence, and they were asked to modify the sentences. Unlike previous studies, there was no question as to guilt or innocence — the only issue was whether the sentence should be more or less than 20 years under the circumstances. A functional MRI scanned their brains to see what neurons were firing as they made their decisions.

The question intrigued the researchers because such decisions are not only high-stakes, but also because one must first have an emotional reaction, and then convert it into a cold quantification — the number of years of the sentence.

After crunching all the numbers, there appeared to be a strong correlation between activity in the portions of the brain highlighted in the image above, and reduced sentences.

To their credit, the researchers really don’t conclude any more than that — that certain brain areas seem to be involved in decisionmaking influenced by sympathy. And someone who’s more likely to be sympathetic is also more likely to have more activity in those neurons.

But they do note that this raises other questions — such as to what extent (more…)

Not Ready for Prime Time: Brain-Scan Reliability in Question

Tuesday, March 13th, 2012

Almost from our first post, we’ve written here about developments in brain-scan technology and its applicability to criminal law (see here, here, here and here, for example). So needless to say, the past nine days have been of great interest, as the research behind neuroimaging’s claims has come into hot dispute.

Now, just because our motto is “truth, justice and the scientific method,” that doesn’t make us qualified to assess the merits of the underlying science. Our observations on the actual science wouldn’t be worth the pixels. But fortunately, as with most such disputes, the issue isn’t so much the data as the math — the statistical analysis being used to make sense of the data. And we’re somewhat confident that we can at least report on such issues without getting them too wrong.

So briefly what’s going on is this:

First, lots of neuroimaging papers out there, some very influential, see apparent connections between brain activity at point X and mental state A. But what are the odds your reading of X was just a fluke, and the real spot is somewhere else, over at Z? If you do enough tests, you’re going to see X every now and then just by chance. So you have to figure out what the chances are that X would be a random result, instead of the real thing, and apply that correction to your statistical analysis. As it happens, however, for a long time the neuroimaging folks weren’t using an accurate correction. Instead, they were applying a lax rule-of-thumb that didn’t really apply. It’s since been shown that using the lax math can result in apparent connections to variables that didn’t even exist at the time.

On top of all that, as neuroscientist Daniel Bor mentions in his excellent (and much more detailed) discussion here, there’s reason to suspect that (more…)