Chapter 4: Picturing Scientific Evidence

Detail of fMRI data set
courtesy of Todd Constable

The authors talk about Chapter 4: Picturing Scientific Evidence

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Chapter 4, Picturing Scientific Evidence: Expert scientific testimony is often complex and hard for laypeople to understand, so many experts accompany their words with pictures of the reality on which their scientific opinions are based. Determining when these pictures should be shown in court can be complicated. We care very much about whether scientific pictures represent reality accurately enough to be relied upon, but the pictures often don’t look anything like what a witness with unaided vision would have seen. So how do we know that they’re truthful, especially when digital pictures can so easily be manipulated? Moreover, laypeople usually can’t understand scientific pictures on their own; they need the expert witness to help them interpret the pictures, just as they may need the pictures to understand the expert’s testimony. What should courts do about the ever-present possibility that jurors, drawing on their common sense visual habits, will read the pictures differently than the experts would?

We discuss two examples. In the first, the prosecution used digital tools to combine photographs of bite marks and teeth into a kind of “information sandwich,” yielding a visual match between the accused murderer’s teeth and the marks on his victim’s body. In the second, we look at the promise and perils of lawyers’ use of fMRI (functional magnetic resonance imaging) as visual proof of their clients’ legally relevant mental states.

State of Connecticut v. Swinton:

Information about Lucis software:

For a Lucis white paper on the forensic odontology images used in the Swinton case, including the pictures, see:

Photographic truth:

“A Brief Guide to Reuters Values and Standards,” davidschlesinger/page/2/

Hany Farid, “Photo Tampering Throughout History,”

Errol Morris, “Photography as a Weapon,”

For examples of how photographs can be altered layer by layer in Photoshop, see Sébastien Gaucher, Click on “Tutorials” and choose the second thumbnail from the left (the house).

Mike Rossner, “How to Guard Against Image Fraud” (Journal of Cell Biology); Nature,

For best practices as outlined by the Scientific Working Group on Imaging Technologies, see:

Nicholas Wade, “It May Look Authentic; Here’s How to Tell It Isn’t,” New York Times,

On fMRI:

A discussion of 2008 Indian case in which brain scan evidence was used by the prosecution in a murder trial:

Images and discussions of fMRI and its use in the law are all over the web. For an excellent basic resource on fMRI science and technology, see:

For an amusing example of the continuing controversy over the scientific validity of fMRI, see:

Also of interest:

Picturing what cannot be seen any other way: “The Inner Life of the Cell” William Dembski apparently repurposed some of the material from this film for a counter-to-evolution argument. For a comparison of the two films to distinguish (or not) plagiarism, see “Was “The Inner Life of a Cell" Plagiarized by "Expelled: No Intelligence Allowed"?