Marc Jonathan Blitz

Constitutional Puzzles and (Neuro) Technological Changes

This chapter explains why neuroimaging raises constitutional puzzles, even where constitutional rules at first seem clear. The Fifth Amendment bars compelled self-incrimination and one might assume that would prevent police from circumventing this limit by obtaining evidence of mental states some other way. The Fourth Amendment would almost certain classify neuroimaging as a search, and thus subject it to constitutional limits. However, both of the implications of these provisions are unclear: They seem to leave police with plenty of room to gather physical evidence of various kinds – and there are certain respects in which neuroimaging evidence resembles such physical evidence (as the chapter illustrates with the help of a hypothetical crime investigation). The chapter points to a way ahead and also argues that while the First Amendment isn’t generally considered a kind of privacy protection, its freedom of thought protection may be a key part of solving these puzzles.

Lie Detection, Mind Reading, and Brain Reading

This chapter briefly looks at the ways that those in the mid-to-late twentieth-century developed lie-detection techniques without neuroimaging – and how various neuroimaging techniques promise more sophisticated types of lie detection. It also very briefly explains how different neuroimaging technologies – such as EEF, fMRI, and fNIR – work, and how they might evolve into more sophisticated – and invasive – techniques in the future, and how law enforcement use of them may thus raise privacy concerns (and do so, even in cases that at first seem free of substantial privacy harms).

The Fifth Amendment: Self-Incrimination and the Brain

This Fifth Amendment’s self-incrimination clause has been at the center of constitutional discussions over neuroimaging’s future. That it is not because it clearly would apply to neuroimaging – but rather because neuroimaging raises a easily formulated (albeit difficult to answer) Fifth Amendment puzzle: It seems to count as both of what are supposed to be two mutually exclusive categories in Fifth Amendment law, because it is both like a witness statement (or “testimonial”) and like physical evidence such as blood flow or other physiological processes. This chapter explores various solutions scholars have proposed to this puzzle, rooted in distinctive theories of the self-incrimination clause – and the unanswered questions each of these theories raises. It also emphasizes another point that has received less attention in discussions of self-incrimination and neuroimaging: idea that Fifth Amendment protection for our thoughts and other mental process should perhaps sometimes cover the biology underlying that thinking even when government plausibly claims it wants access to it for reasons other than inferring our thoughts or beliefs.

The Fourth (and First) Amendment:Searches with, and Scrutiny of, Neuroimaging

The questions raised of Fourth Amendment law by neuroimaging at first seem to have simple answers: The Fourth Amendment covers neuroimaging because probing any part of the body’s interior is a “search.” The standard level of protection against such a search is the warrant requirement, imposing on government the responsibility of showing probable cause and specifying the place to be searched before conducting such a search. However, matters are not so simple. There is significant gray area in the Fourth Amendment that the court has used to give government flexibility in meeting vital security interests. This chapter shows that some of the answers to these Fourth Amendment problems may unexpectedly have First Amendment solutions.