The Commonwealth and the United States as amicus curiae argue that this incriminating inference does not trigger the protections of the Fifth Amendment privilege because the inference concerns "the physiological functioning of [Muniz's] brain," Brief for Petitioner 21, which is asserted to be every bit as “real or physical" as the physiological makeup of his blood and the timbre of his voice.

But this characterization addresses the wrong question; that the "fact" to be inferred might be said to concern the physical status of Muniz's brain merely describes the way in which the inference is incriminating. The correct question for present purposes is whether the incriminating inference of mental confusion is drawn from a testimonial act or from physical evidence. In Schmerber, for example, we held that the police could compel a suspect to provide a blood sample in order to determine the physical makeup of his blood and thereby draw an inference about whether he was intoxicated. This compulsion was outside of the Fifth Amendment's protection, not simply because the evidence concerned the suspect's physical body, but rather because the evidence was obtained in a manner that did not entail any testimonial act on the part of the suspect: "Not even a shadow of testimonial compulsion upon or enforced communication by the accused was involved either in the extraction or in the chemical analysis." 384 U. S., at 765. In contrast, had the police instead asked the suspect directly whether his blood contained a high concentration of alcohol, his affirmative response would have been testimonial even though it would have been used to draw the same inference concerning his physiology. See ibid. ("[T]he blood test evidence . was neither [the suspect's] testimony nor evidence relating to some communicative act"). In this case, the question is not whether a suspect's "impaired mental faculties" can fairly be characterized as an aspect of his physiology, but rather whether Muniz's re

v. Griscavage, 512 Pa. 540, 545, 517 A. 2d 1256, 1258 (1986) (emphasis deleted).

sponse to the sixth birthday question that gave rise to the inference of such an impairment was testimonial in nature.'

We recently explained in Doe v. United States, 487 U. S. 201 (1988), that "in order to be testimonial, an accused's communication must itself, explicitly or implicitly, relate a factual assertion or disclose information." Id., at 210. We reached this conclusion after addressing our reasoning in Schmerber, supra, and its progeny:

"The Court accordingly held that the privilege was not implicated in [the line of cases beginning with Schmerber], because the suspect was not required 'to disclose any knowledge he might have,' or 'to speak his guilt.' Wade, 388 U. S., at 222-223. See Dionisio, 410 U. S., at 7; Gilbert, 388 U. S., at 266-267. It is the 'extortion of information from the accused,' Couch v. United States, 409 U. S., at 328, the attempt to force him 'to disclose the contents of his own mind,' Curcio v. United States, 354 U. S. 118, 128 (1957), that implicates the Self-Incrimination Clause. . . . 'Unless some attempt is made to secure a communication-written, oral or otherwise-upon which reliance is to be placed as involving [the accused's] consciousness of the facts and the operations of his mind in expressing it, the demand made upon

"See, e. g., Doe v. United States, 487 U. S. 201, 211, n. 10 (1988) ("[T]he Schmerber line of cases does not draw a distinction between unprotected evidence sought for its physical characteristics and protected evidence sought for its [other] content. Rather, the Court distinguished between the suspect's being compelled himself to serve as evidence and the suspect's being compelled to disclose or communicate information or facts that might serve as or lead to incriminating evidence") (emphasis added); cf. Baltimore Dept. of Social Services v. Bouknight, 493 U. S. 549, 555 (1990) (individual compelled to produce document or other tangible item to State "may not claim the [Fifth] Amendment's protections based upon the incrimination that may result from the contents or nature of the thing demanded" but may "clai[m] the benefits of the privilege because the act of production would amount to testimony").

him is not a testimonial one.' 8 Wigmore § 2265, p. 386." 487 U. S., at 210-211.

8

After canvassing the purposes of the privilege recognized in prior cases, we concluded that "[t]hese policies are served when the privilege is asserted to spare the accused from having to reveal, directly or indirectly, his knowledge of facts relating him to the offense or from having to share his thoughts and beliefs with the Government." Id., at 213.

This definition of testimonial evidence reflects an awareness of the historical abuses against which the privilege against self-incrimination was aimed. "Historically, the privilege was intended to prevent the use of legal compulsion to extract from the accused a sworn communication of facts which would incriminate him. Such was the process of the

8 See Doe, supra, at 212-213 (quoting Murphy v. Waterfront Comm'n of New York Harbor, 378 U. S. 52, 55 (1964) (internal citations omitted)): "[T]he privilege is founded on 'our unwillingness to subject those suspected of crime to the cruel trilemma of self-accusation, perjury or contempt; our preference for an accusatorial rather than an inquisitorial system of criminal justice; our fear that self-incriminating statements will be elicited by inhumane treatment and abuses; our sense of fair play which dictates "a fair state-individual balance by requiring the government . . . in its contest with the individual to shoulder the entire load," . . . ; our respect for the inviolability of the human personality and of the right of each individual "to a private enclave where he may lead a private life," ...; our distrust of self-deprecatory statements; and our realization that the privilege, while sometimes "a shelter to the guilty," is often "a protection to the innocent."""

This definition applies to both verbal and nonverbal conduct; nonverbal conduct contains a testimonial component whenever the conduct reflects the actor's communication of his thoughts to another. See Doe, supra, at 209-210, and n. 8; Schmerber v. California, 384 U. S. 757, 761, n. 5 (1966) (“A nod or head-shake is as much a 'testimonial' or 'communicative' act in this sense as are spoken words"); see also Braswell v. United States, 487 U. S. 99, 122 (1988) (KENNEDY, J., dissenting) ("Those assertions [contained within the act of producing subpoenaed documents] can convey information about that individual's knowledge and state of mind as effectively as spoken statements, and the Fifth Amendment protects individuals from having such assertions compelled by their own acts").

At

ecclesiastical courts and the Star Chamber-the inquisitorial method of putting the accused upon his oath and compelling him to answer questions designed to uncover uncharged offenses, without evidence from another source. The major thrust of the policies undergirding the privilege is to prevent such compulsion." Id., at 212 (citations omitted); see also Andresen v. Maryland, 427 U. S. 463, 470-471 (1976). its core, the privilege reflects our fierce "unwillingness to subject those suspected of crime to the cruel trilemma of self-accusation, perjury or contempt,'" Doe, 487 U. S., at 212 (citation omitted), that defined the operation of the Star Chamber, wherein suspects were forced to choose between revealing incriminating private thoughts and forsaking their oath by committing perjury. See United States v. Nobles, 422 U. S. 225, 233 (1975) (“The Fifth Amendment privilege against compulsory self-incrimination . . . protects 'a private inner sanctum of individual feeling and thought and proscribes state intrusion to extract self-condemnation'") (quoting Couch v. United States, 409 U. S. 322, 327 (1973)).

We need not explore the outer boundaries of what is "testimonial” today, for our decision flows from the concept's core meaning. Because the privilege was designed primarily to prevent "a recurrence of the Inquisition and the Star Chamber, even if not in their stark brutality," Ullmann v. United States, 350 U. S. 422, 428 (1956), it is evident that a suspect is "compelled . . . to be a witness against himself" at least whenever he must face the modern-day analog of the historic trilemma-either during a criminal trial where a sworn witness faces the identical three choices, or during custodial interrogation where, as we explained in Miranda, the choices are analogous and hence raise similar concerns. Whatever

10 During custodial interrogation, the pressure on the suspect to respond flows not from the threat of contempt sanctions, but rather from the "inherently compelling pressures which work to undermine the individual's will to resist and to compel him to speak where he would not otherwise do so freely." Miranda v. Arizona, 384 U. S. 436, 467 (1966). Moreover,

else it may include, therefore, the definition of "testimonial" evidence articulated in Doe must encompass all responses to questions that, if asked of a sworn suspect during a criminal trial, could place the suspect in the "cruel trilemma." This conclusion is consistent with our recognition in Doe that "[t]he vast majority of verbal statements thus will be testimonial" because "[t]here are very few instances in which a verbal statement, either oral or written, will not convey information or assert facts." 487 U. S., at 213. Whenever a suspect is asked for a response requiring him to communicate an express or implied assertion of fact or belief," the suspect confronts the "trilemma" of truth, falsity, or silence, and hence the response (whether based on truth or falsity) contains a testimonial component.

This approach accords with each of our post-Schmerber cases finding that a particular oral or written response to express or implied questioning was nontestimonial; the questions presented in these cases did not confront the suspects with this trilemma. As we noted in Doe, supra, at 210-211, the cases upholding compelled writing and voice exemplars did not involve situations in which suspects were asked to communicate any personal beliefs or knowledge of facts, and therefore the suspects were not forced to choose between

false testimony does not give rise directly to sanctions (either religious sanctions for lying under oath or prosecutions for perjury), but only indirectly (false testimony might itself prove incriminating, either because it links (albeit falsely) the suspect to the crime or because the prosecution might later prove at trial that the suspect lied to the police, giving rise to an inference of guilty conscience). Despite these differences, however, "[w]e are satisfied that all the principles embodied in the privilege apply to informal compulsion exerted by law-enforcement officers during in-custody questioning." Id., at 461; see id., at 458 (noting "intimate connection between the privilege against self-incrimination and police custodial questioning").

"As we explain infra, at 600-601, for purposes of custodial interrogation such a question may be either express, as in this case, or else implied through words or actions reasonably likely to elicit a response.