Fox discussed in The Atlantic article on Brain Imaging and the Right to Silence

A new article in The Atlantic, “Could the Government Get a Search Warrant for Your Thoughts?: Why remain silent if they can just read your mind?“, cites Bill of Health blogger Dov Fox’s research on brain imaging.

Last year, a Maryland man on trial for murdering his roommate tried to introduce results from an fMRI-based lie detection test to bolster his claim that the death was a suicide. The court ruled the test results inadmissible, noting that the “fMRI lie detection method of testing is not yet accepted in the scientific community.” In a decision last year to exclude fMRI lie detection test results submitted by a defendant in a different case, the Sixth Circuit was even more skeptical, writing that “there are concerns with not only whether fMRI lie detection of ‘real lies’ has been tested but whether it can be tested.”

So far, concerns regarding reliability have kept thought-inferring brain measurements out of U.S. (but not foreign) courtrooms. But is technology the only barrier? Or, if more mature, reliable brain scanning methods for detecting truthfulness and reading thoughts are developed in the future, could they be employed not only by defendants hoping to demonstrate innocence but also by prosecutors attempting to establish guilt? Could prosecutors armed with a search warrant compel an unwilling suspect to submit to brain scans aimed at exploring his or her innermost thoughts?


The central constitutional question relates to the Fifth Amendment, which states that “no person … shall be compelled in any criminal case to be a witness against himself.” In interpreting the Fifth Amendment, courts have distinguishedbetween testimonial evidence, which is protected from compelled self-incriminating disclosure, and physical evidence, which is not. A suspected bank robber cannot refuse to participate in a lineup or provide fingerprints. But he or she can decline to answer a detective who asks, “Did you rob the bank last week?”

So is the information in a brain scan physical or testimonial? In some respects, it’s a mix of both. As Dov Fox wrote in a 2009 law review article, “Brain imaging is difficult to classify because it promises distinctly testimonial-like information about the content of a person’s mind that is packaged in demonstrably physical-like form, either as blood flows in the case of fMRI, or as brainwaves in the case of EEG.” Fox goes on to conclude that the compelled use of brain imaging techniques would “deprive individuals of control over their thoughts” and be a violation of the Fifth Amendment.

Read the full article here.

Dov Fox

Dov Fox

Dov Fox is Professor of Law and the Director of the Center for Health Law Policy and Bioethics at the University of San Diego School of Law, where he has been named Herzog Endowed Scholar for exceptional scholarship and teaching. He also won BIOCOM's Life Science Catalyst Award for "significant contributions to human health through research, discovery, and entrepreneurship." His work has been featured in CNN, ABC, NPR, NBC, Reuter’s, Bloomberg, Slate, Daily Beast, Today Show, Boston Globe, and Washington Post. His latest book project, "Birth Rights and Wrongs," is forthcoming with Oxford University Press.

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