dissenting.
Defendant, Darryl Pitts, was prosecuted under the capital murder-death penalty statute for the murders of Paul Reynolds and Stacey Elizardo. Defendant was convicted of both murders and sentenced to death for the murder of Stacey Elizardo; he was sentenced to life imprisonment with thirty-years parole ineligibility for the murder of Paul Reynolds. He was also tried and convicted of several other related offenses. The Court affirms his convictions for murder and the related offenses, while reversing the death sentence and remanding the matter to the trial court for a new sentencing proceeding. I would reverse defendant’s murder convictions, and, therefore, dissent from the Court’s judgment.
I note initially my continuing belief that our capital murder-death penalty statute as enacted, interpreted, and applied violates state-constitutional and fundamental-fairness doctrines. I adhere to this position in light of the continuing development of capital-murder jurisprudence, and because, as I see it, the flaws in our state’s statute are too severe to be ignored. However, it is not necessary here either to reiterate or further explain these grounds for disagreement. See, e.g., State v. Hunt, 115 N.J. 330, 390 (1989) (Handler, J., dissenting).
Nevertheless, in this case, I am in profound disagreement with the resolution of two issues by the Court. One issue involves the conceded failure of the trial court to give the jury an instruction concerning the non-capital offense of serious-bodily-injury murder, that is, murder involving serious bodily injury inflicted without homicidal intent or knowledge. Indisputably, this charge is supported by a rational basis in the evidence and is clearly mandated by State v. Gerald, 113 N.J. 40, 69-91 (1988). The other issue arises from the exclusion by the trial *641court of important and competent expert testimony concerning the defendant’s state of mind, an exclusionary ruling that is affirmed by this Court not only with respect to the guilt phase of the trial but also the penalty phase, a ruling that, presumably, will apply in the defendant’s retrial to impose the death penalty.
I note, in addition, the Court also rejects defendant’s contention that, particularly in light of the later-decided case of State v. Bowens, 108 N.J. 622 (1987), he was entitled to a charge of aggravated manslaughter. Ante at 603-614. I am of the view that defendant is entitled to a charge of aggravated manslaughter with respect to the murder of Stacey Elizardo. The line between knowing murder, serious-bodily-injury murder, and aggravated manslaughter is simply too fine and fragile to justify withholding from a jury the choice among these several offenses in light of evidence that would support any one of them. I reach this conclusion — that defendant is entitled to an aggravated manslaughter charge — particularly in light of evidence that provides a rational basis to support a charge for serious-bodily-injury murder under our Gerald decision as well as the evidence in support of defendant’s claim of imperfect self-defense and diminished capacity. See discussion infra at 641-650. My reasons for these conclusions are expressed substantially in my dissent in State v. Rose, 112 N.J. 454, 552-67 (1988), as well as my later dissent in State v. Hunt, supra, 115 N.J. at 403-411, and will not be reiterated here.
I.
This case was tried before we rendered our decision in State v. Gerald. Hence, no one involved in this prosecution anticipated the significance of the evidence that the defendant may have committed a homicide intending to inflict serious bodily injury that resulted in death but without the intent or certain *642knowledge that death would in fact occur. Gerald explains the significance of such evidence. We there held that a defendant
who is convicted of purposely or knowingly causing “serious bodily injury resulting in death” under N.J.S.A. 2C:ll-3(a)(l) and (2), or either of them — as opposed to one who is convicted of purposely or knowingly causing death under those same provisions — may not be subjected to the death penalty. [113 N.J. at 69.]
In charging the jury in this case without having the benefit of our holding in Gerald, the trial court did not require the jury to determine specifically whether defendant purposely or knowingly caused the death of the victims, or, alternatively, whether defendant purposely or knowingly caused serious bodily injury that happened to result in their deaths.
The Court now rules that the trial court’s omission to charge the jury as mandated by Gerald is of no consequence with respect to defendant’s conviction for the murder of Paul Reynolds because the jury did not impose the death penalty. Ante at 615. Hence, it concludes that defendant was exposed to the same sentence that could have been imposed were he to have been convicted of non-capital murder. Ibid. I disagree with this determination essentially for the reasons expressed in my dissenting opinion in State v. Hunt, supra, 115 N.J. at 389.
The Court deals more pointedly with the conviction for the murder of Stacey Elizardo, for which defendant was sentenced-to death. The Court poses the issue as follows: whether the evidence in the record concerning that homicide so clearly established that defendant purposely or knowingly caused her death that the trial court’s omission of the Gerald charge was not capable of affecting the jury’s verdict, ante at 615; and “whether the jury’s verdict effectively constituted a determination that defendant purposely or knowingly caused the victim’s death.” Ante at 615. The Court then finds that the record clearly established and the verdict of the jury “effectively constituted a determination that defendant purposely or knowingly caused the death of Stacey Elizardo.” Ante at 619-620. It concludes, accordingly, that the omission of the Gerald *643charge “was not capable of affecting the jury’s verdict.” Ante at 620. I disagree with this reasoning and conclusion.
In Gerald, we posited the standard for determining when the infliction of serious bodily injury must result in an alternative charge to intentional murder:
Because the jury in this case did not specify which of the foregoing offenses ' (capital murder or non-capital murder) defendant was convicted of, and because it is possible, on this record, that the jury could have determined that the defendant had the purpose or knowledge to cause only serious bodily injury but not death, we conclude that the judgment of conviction ... must be reversed and the cause remanded for retrial. [113 N.J. at 69-70.]
The Court grudgingly follows this standard. Nevertheless, while it acknowledges that the Gerald charge, encompassing as it does a lesser-included murder offense,1 need be supported only by a rational basis in the evidence, State v. Crisantos, 102 N.J. 265, 276 (1986), it ignores the essential teachings of Gerald, as well as Crisantos. It hypothesizes the weight a jury would have ascribed to the evidence supporting serious-bodily-injury murder relative to the evidence supporting purposeful or knowing murder. The Court’s conclusion then is dictated by its own comparative assessment of the weight of the evidence it ascribes respectively to the alternative offenses. Such an approach is not only contrary to our holding in Gerald, but essentially usurps the function of the jury. Hunt, 115 N.J. at 405 (Handler, J., dissenting).
In State v. Rose, supra, 112 N.J. 454, the defendant was convicted of capital murder and sentenced to death for the fatal shooting of a police officer. On appeal, the defendant alleged as reversible error the trial court’s refusal to charge the jury on aggravated manslaughter. There was evidence that the defendant shot the officer in the stomach from very close range with a sawed-off shotgun; the shooting was witnessed, and defen*644dant had confessed to it. A majority of this Court relied on the weight of this evidence to conclude that defendant’s firing of the shotgun was intentional rather than accidental, and thus found no rational basis for allowing the jury to consider aggravated manslaughter as a possible verdict. Id. at 482-83.
Two members of the Court disagreed with this position because there was also evidence in the record that could allow a jury to conclude that the defendant had shot the officer reflexively out of panic. In their view, this could implicate the requisite state of mind for aggravated manslaughter: recklessness manifesting extreme indifference to human life. Id. at 550 (Wilentz, C.J., concurring in part and dissenting in part); id. at 556-60 (Handler, J., dissenting). Thus, both concluded that the jury should have been permitted to decide whether defendant’s panic caused him to act recklessly.
Subject to particular dispute in Rose was the Court’s novel approach to the question of whether a rational basis existed for charging the lesser-included offense of aggravated manslaughter. As I pointed out in dissent, the Court’s approach constituted a new formulation of the law, according to which a “rational basis is not established unless a defendant has not only pointed to evidence that could support a conviction on the lesser charge, but also, and quite apart from this, explained why the jury should have credited that evidence by assailing the strength of the evidence of the greater charge.” Id. at 560; Hunt, 115 N.J. at 405 (Handler, J., dissenting). Never before had we required a defendant to establish a rational basis for an instruction on a lesser offense by disproving the case for the greater charge in order to increase the weight a jury would give to the lesser charge. Nor have we required courts to hypothesize the weight a jury would have ascribed to the evidence supporting conviction of the lesser charge. Because the degree to which a jury will believe and weigh evidence is essentially inscrutable, the question of what weight to afford evidence supporting a lesser charge had previously been left exclusively to the jury. Id. 112 N.J. at 560; Hunt, 115 N.J. at 405 (Handler, J., dissenting). I therefore concluded in Rose that to the extent *645the majority’s approach required courts to assess the weight of the evidence of the lesser offense as against the weight of the greater in order to determine whether a rational basis exists to charge the lesser offense, “it departs from all precedent, imposes an unrealistic standard, and usurps the function of the jury.” Id. 112 N.J. at 560; Hunt, 115 N.J. at 405 (Handler, J., dissenting).
So too in this case has the Court engaged in a process of review that requires a court to hypothesize the weight a jury would have ascribed to the evidence supporting the conviction of the lesser charge if, indeed, that charge had been given. The Court’s approach essentially compares the weight of the evidence supporting the lesser crime, serious-bodily-injury murder, to that of the greater offense, purposeful or knowing murder, in order to determine which was the jury’s most probable verdict. Hunt, 115 N.J. at 405-406 (Handler, J., dissenting). But the standard in Gerald is whether “it is possible ” the jury could have determined that the defendant’s intention was merely to cause serious bodily injury and not death.
The Court does not deal with the evidence in terms of possibilities. Rather it assesses the weight of the evidence, and, in determining its weight, it simply accepts the State’s view of the evidence, thus leaving it, not surprisingly, with “no doubt” that defendant purposely or knowingly killed Stacey Elizardo. Ante at 617. Illustrative of this approach is the Court’s reference to the testimony of the medical examiner concerning the number and depth of the wounds defendant inflicted on Elizardo, from which it concludes that it would be “inconceivable” for the jury to have found that defendant meant to cause serious bodily injury but not death. Ante at 620. It must be assumed that by this conclusion the Court has found, as it must to satisfy Gerald, that “it is [not] possible” *646for the jury to have determined from any evidence that defendant meant to cause serious bodily injury but not death.
Defendant does not dispute the severity of the wounds inflicted during his assault of Elizardo; or that there is evidence, indeed abundant evidence, sufficient to prove murder. The point is that defendant is not obligated to disprove or overcome that evidence. Eather, it suffices to identify other evidence and to show that this evidence itself renders it “possible” for the jury to have concluded that the defendant intended to inflict serious bodily injury, not death.
And there was other evidence. Thus, on direct examination defendant stated:
The actual assault was like almost an instantaneous like reflex for me to have assaulted him. I assaulted Paul with the knife; while I was doing so, from back of me was, it was like a frenzied-type state of mind, ... it was just an image at that time____
Further, on cross-examination defendant stated:
I want the jury to believe that I didn’t have the intentional thought to harm these people.
Moreover, Dr. Cooke testified that defendant told him he was initially unaware that he was assaulting Stacey Elizardo:
He [defendant, Pitts] also then tells me that out of the corner of his eye he saw what at some times [sic] he described as an image, as a person, didn’t know who it was, he says, didn’t know if it was a male or female, but had a feeling very much like the feeling that he had when he was in Vietnam, I have to win, I have to survive, I am under attack, things of that nature.
I went into this with him in great detail; this is not a flashback into any specific incident, that is not like he is reliving a specific incident in Vietnam. I am not saying that. What I am saying, he had the general feeling under this stressful situation that he had had at times in Vietnam in just having to win, having to survive, having to strike out until there was no more motion around him. He said that he only afterwards realized that that was Stacey.
Contrary to the conclusion reached by the Court, in the absence of a correct Gerald charge, one cannot be totally convinced that the jury verdict convicting Pitts of the murder of Stacey Elizardo necessarily reflected a determination by the jury that the defendant only purposely or knowingly caused death and did not merely intend to cause serious bodily injury that resulted in death. Although the weight of the evidence *647that defendant purposely or knowingly caused the death of Stacey Elizardo was great, it did not extinguish evidence to the contrary, namely, evidence suggesting that defendant struck out blindly at an “image” in a “frenzied-type state of mind” intending only generalized harm. It is thus conceivable that a properly charged jury would have convicted defendant of non-capital murder.
The Court, as it did to some extent in Rose, seems to buttress its own evaluation of the record by referring to defendant’s trial strategy to support its conclusions. The Court relies in part on defense counsel’s opening statement to the jury concerning defendant’s state of mind as involving rage; it also notes that defense counsel made comparable statements in summation. Further, it emphasizes that the jury was instructed on passion/provocation manslaughter. The Court thus seems to suggest that defendant’s trial strategy itself somehow engenders an estoppel or waiver of a Gerald argument or, because his manslaughter strategy is consistent with an intentional killing, it can be seen, by hindsight, as a kind of clairvoyant acquiescence in the fortuitous omission of non-capital murder from the case. However, defense counsel was not prescient; the Court unfairly ignores the fact that prior to Gerald, non-capital murder was not available to the defendant as the basis for a plausible alternative theory to present to the jury and that his trial strategy was devised when it was impossible to know that the Gerald principle existed or could be applicable to the case.
The Court also concludes that the jury’s verdict of murder, rather than manslaughter, was a rejection of defendant’s contention that he killed in the heat of rage or passion brought on by reasonable provocation. Ante at 618-619. Because the Court urges that the rejection of manslaughter by the jury is inconsistent with a view of the evidence that would support serious-bodily-injury murder, implicit in the Court’s reasoning is the belief that this verdict — the rejection of manslaughter— must have included specifically the rejection of any evidence of *648“rage.” The Court seems also then to assume that the rejection of “rage” serves to negate a state of mind that would constitute an intent only to harm by inflicting serious bodily injury. However, the consideration of manslaughter by the jury did not invite it to differentiate and consider discretely the evidence of rage apart from that of provocation. Hence, the rejection of manslaughter does not signify necessarily its disbelief of the evidence of rage. Moreover, the jury’s verdict rejecting manslaughter was predicated on an unfair choice: that between intentional murder and manslaughter; the choice was not augmented by another alternative, namely, non-capital murder. Thus, the jury’s verdict rejecting manslaughter may not be inconsistent with the theory — not presented to the jury— that defendant killed in a “frenzied-type state of mind” that could under a correct charge reduce the homicide to non-intentional murder.
In State v. Bey (I), 112 N.J. 45, 93-95 (1988), we indicated that “in assessing the impact of error in either the guilt or penalty phase of a capital case, we shall continue to determine reversibility on the basis of a qualitative determination that considers, in the context of the entire case, whether the error was clearly capable of affecting either the verdict or the sentence.” Applying this standard, the Court professes to have made a meticulous review of the record in this case, convincing itself that the jury’s verdict was a determination that defendant purposely or knowingly caused the death of Stacey Elizardo. It thus appears that in the view of the Court, the trial court’s omission of the charge required by our decision in Gerald was not capable of affecting the jury’s verdict. The Court also concludes, under an alternative enhanced standard of review, that “there was no realistic likelihood of prejudice” resulting from such omission. State v. Bey (I), 112 N.J. at 116 (Handler, J., concurring).
For purposes of appellate review, the Court in effect defines the decisive question as a factual one: whether the assault had as its objective serious bodily injury or death. Ante at 619. *649That, I suggest, is the decisive question that the jury should consider and determine. It is not, however, the decisive question for this Court. Rather that question is whether there was a rational basis in the evidence to establish such an offense and whether it was possible for the jury to make such a determination. Hence, the Court’s own recapitulation of the evidence and its own factual determination, consisting entirely of the evidence demonstrating either defendant’s purpose to kill or his knowledge that death was practically certain to occur, cannot be dispositive of defendant’s entitlement to the ordinary-murder charge. Hunt, 115 N.J. at 405-407 (Handler, J., dissenting).
The Court may be saying that it is truly unimportant that the jury in this case did not consider the full range of charges relating to offenses available under the evidence, including ordinary murder. Such an approach trivializes the jury role. We have held that at the very core of the guarantee of a fair trial in a criminal case is the judicial obligation to assure that the jury’s impartial deliberations are based solely on the evidence and in accordance with proper and adequate instructions. State v. Simon, 79 N.J. 191, 206 (1979). When a lesser-included offense charge is requested by a defendant, the trial court is obligated to determine if there exists a rational basis in the evidence that could support the included offense. State v. Crisantos, supra, 102 N.J. at 278. Indeed, “so paramount is the duty to insure a fair trial that a jury must deliberate in accordance with correct instructions even when such instructions are not requested by counsel.” State v. Grunow, 102 N.J. 133, 148 (1986); see State v. Moore, 113 N.J. 239, 288 (1988) (trial court’s failure to charge jury on diminished capacity constitutes reversible error although charge was never requested by defense counsel). The court has an obligation to see to it that the jury, as the representative of the public, is given all of the facts and all of the possible offenses that might reasonably be found from such facts.” State v. Choice, 98 N.J. 295, 298-99 (1985).
*650What the Court has done, simply, is to act as a thirteenth juror, weighing the evidence with its own thumb on the scale. The Court, from its appellate promontory, has effectively co-opted the jury. Its recapitulation of the evidence reads like the prosecutor’s summation; its conclusion, a jury verdict. What is missing from this exercise in judicial review is a genuine and cogent rebuttal to the irrefutable facts: there was a rational basis in the evidence for the jury to find non-capital murder, it was possible for the jury to credit that evidence, the Gerald charge was not given, and the jury had no opportunity to consider such evidence in terms of such a charge.
Measured by these omissions, not by whether the jury’s ultimate determination would or would not have been the same, sound appellate review must record the fundamental prejudice that affected the jury’s deliberations. The jury was denied the opportunity to engage in full deliberations involving all the evidence in accordance with complete instructions. This cannot be passed off as harmless error in a capital-murder prosecution.
II.
The Court concludes that the trial court properly excluded expert testimony based in part on the results of a sodium amytal examination of the defendant. The trial court, and now this Court, misunderstand the nature and purpose of the evidence offered, misperceive the issue posed by this critical evidence, and misapply relevant standards governing the admissibility of expert evidence. This evidence, in my view, should have been held admissible in the guilt phase of this prosecution. More importantly, its exclusion from the penalty phase of defendant’s trial is particularly indefensible in light of the unique and portentous significance that a sentencing trial holds in death-penalty prosecutions.
The subject of the trial court’s exclusionary ruling was the testimony consisting of the expert opinion of Dr. Robert Sadoff relating to his examination of the defendant with the use of *651sodium amytal. This substance is a barbiturate with some utility as a relaxant that blocks anxiety and allows psychiatrists engaging in narcoanalysis to call forth repressed or suppressed memories or feelings that are otherwise difficult to reach. From this examination, Dr. Sadoff elicited information concerning defendant’s state of mind at the time of the murders indicating that defendant believed that Paul Reynolds was causing Stacy Elizardo to engage in prostitution. Dr. Sadoff formed the opinion that this belief of the defendant engendered a state of rage in which he murdered his victims.
This evidence was excluded by the trial court. The Court now predicates its approval of the trial court’s exclusion of this evidence on two factors: the use of the sodium amytal interview as a means to ascertain the “truth” of defendant’s belief or motive for killing the victim, and the trial court’s offer to allow expert opinion testimony from Dr. Sadoff so long as it was based on a hypothetical question consistent with the evidence in the case exclusive of any information gleaned from the sodium amytal interview.
This evidence, relating as it does to the defendant’s state of mind, goes to the very core of both the prosecution and the defense of this case. In my opinion, if its exclusion is error, then the error, inescapably, was gravely prejudicial. For this reason, assessment of the court’s exclusionary ruling entails an extended analysis involving (a) a review of the actual testimony concerning the reliability of the sodium amytal methodology as an aspect of psychiatric evidence, (b) the actual use of this methodology by the expert in this case, (c) the standards that should govern the admissibility of its use, (d) a review of the trial court’s ruling, and (e) the prejudicial effect of the exclusionary ruling. Finally, and most importantly, the conclusions drawn from this analysis must be reconsidered in the context of the trial court’s exclusion of this evidence from the sentencing phase of the trial.
*652A.
Because of its potency as a means of investigating a patient’s mind, all of the testifying experts agreed on the legitimacy of using sodium amytal for diagnostic purposes. There was agreement also that sodium amytal could assist patients in reliving repressed events or helping them to “get to” memories or feelings that they are otherwise unable to articulate. Further, two of the three experts felt that the information gleaned from such interviews, in conjunction with other available information, could serve to provide a reliable basis for determining a historical state of mind.
The experts further concurred that the results of a sodium amytal interview are not considered scientifically reliable for the purpose of ascertaining truth as such. Nevertheless, the results of sodium amytal are useful. Dr. DiGiacomo, a defense expert, stated that even if an amytal interviewee was withholding some truth, the manner in which the interviewee defended information would provide insight about the interviewee’s psychological defense mechanisms. Such clues could inform the interviewer of what issues are highly charged or emotionally difficult for the interviewee; thus, although such interviews might not yield “truth” per se, they could provide insight regarding an interviewee’s “style of being in the world.” Dr. DiGiacomo further stated that if asked to give an opinion regarding a defendant’s historical state of mind, he would use a sodium amytal interview to ascertain whether a traumatic neurosis is present or to learn more about what was going on inside the interviewee’s mind by evaluating, among other things, the interviewee’s manner of response to particular topics as well as the substance of any statements made under the influence of the drug. He concluded that the results of a sodium amytal interview, in conjunction with the results of other interviews and psychological tests, would allow him to offer a psychiatric opinion regarding defendant’s historical state of mind. Dr. Sadoff stressed the acceptability throughout the profession of sodium amytal examination as a procedure *653used to allow patients to overcome psychological blocking of traumatic events or emotions. He also stated that sodium amytal could serve as a “face-saving” device, providing in effect a pretext or “permission” for interviewees to talk about topics that they could not otherwise address openly. The State’s witness, Dr. Orne, testified that for treatment purposes, the emotional significance of an interviewee’s recollection is more important than historical accuracy.
Each of the experts also agreed that the likelihood of truthfulness during a sodium amytal interview was greatest when the subject experiences abreaction, a state in which the individual appears to relive past events. The experts differed, however, with regard to the reliability of an abreaction and the relative reliability of other states that fall short of outright abreaction. Dr. DiGiacomo expressed confidence in the utility of non-abreactive interviews, stating that even in the absence of abreaction, psychiatrists could still gain valuable material about a subject’s defense mechanisms. Dr. Sadoff also expressed the belief that results achieved during abreaction would be relatively reliable, but further stated that statements made during a non-abreactive state while under sodium amytal would still be more reliable than statements made without any sodium amytal at all. Dr. Orne maintained that a subject could be untruthful or inaccurate even during an abreaction, and that during a state of non-abreaction, the potential for inaccuracy or untruthfulness was significant due to increased ego control.
Each of the experts also agreed that the use of leading questions during sodium amytal interviews is problematic. While they agreed that rejection of a topic suggested by a leading question would generally indicate irrelevance to a subject’s preoccupations, they also cited the problem of suggestibility. Dr. DiGiacomo testified that the effect of leading questions would vary with the personality of the interviewee; either the question will have a suggestive effect, or will goad a rebellious interviewee into going the opposite way. Dr. Sadoff also acknowledged that leading questions were not ideal, but *654testified that if abreaction is not reached, then such questions must be used carefully in trying to push an interviewee along. Dr. Orne stated that leading questions not only invite suggestibility, but also foreclose the possibility that an interviewee will spontaneously provide new paths of inquiry.
B.
The problem, however, is that these experts fell into two camps with regard to the ultimate purpose or usefulness of the sodium amytal interview in this case. Dr. Orne stated that this sodium amytal interview was used solely as a truth-telling device to identify which of defendant’s versions of his state of mind during the murders was the truth, and that sodium amytal is unreliable for this purpose. The other experts, however, each testified that even though sodium amytal cannot be relied on to ascertain the truth of a matter, other significant insights are attained through interviews such as this one, which in combination with other evidence can form a basis for determining state of mind.
In this case, Dr. Sadoff had conducted previous examinations of the defendant. Indeed, in formulating his final report on defendant’s state of mind, Dr. Sadoff drew on two interviews in addition to the one conducted with sodium amytal, background material supplied by defense counsel that included witness statements, and a report by Dr. Gerald Cooke, who had conducted a number of standard psychological tests with defendant. Dr. Sadoff found in his second interview of the defendant, which preceded the examination under sodium amytal, that defendant was “much more open ... and much more honest.” At that time, defendant indicated his involvement in the murders, but also supplied information pertaining to his combat duty in Vietnam that suggested a relationship between the circumstances of the murders and the possibility that defendant suffered from post-Vietnam delayed stress syndrome. In order to diagnose defendant and investigate whether his actions *655resulted from this syndrome, Dr. Sadoff undertook the sodium amytal interview.
During the sodium amytal examination defendant did not have an “abreaction,” a reliving of his Vietnam experience that would indicate the existence of Vietnam stress syndrome. Further, defendant did not affiliate with leading questions intended to draw out a Vietnam flashback. Dr. Sadoff thus concluded, and none of the other testifying experts disagreed, that delayed stress syndrome did not trigger defendant’s actions. However, during this interview, defendant did provide information that greatly impressed Dr. Sadoff:
without [my] leading, asking him what was going on at the time, what turned out was that he gave a motivation or a reason that I had never heard before, that wasn’t written down any place before and that he elaborated upon under the influence of sodium amytal to a degree that indicated to me that is what he perceived to be what was happening at the time in his own mind, at the time of the killing.
Each of the experts had seen a videotape of defendant’s interview and agreed that no abreaction had occurred. Assessment of the conduct of this interview focused on the extent to which defendant retained conscious control over his responses, and the effect of leading questions. At the Rule 8 hearing, Dr. Sadoff was vigorously cross-examined with regard to his use of leading questions. The prosecutor challenged his choice of leading questions as indicative of a failure to investigate certain possibilities, including other motives consistent with defendant’s prior stories of killing in revenge for non-payment of debts. Moreover, cross-examination revealed that defendant spontaneously brought up the issue of Reynolds’ attempt to turn Elizardo into a prostitute, and did so in a contradictory way by following his initial thought with the statement “nah, no way. Women don’t need that,” prompting Dr. Sadoff’s follow-up that introduced the word “pimping” and related this term to the argument between defendant and Reynolds. Further, Dr. Sadoff conceded that defendant possessed some measure of self-control during the latter portion of the interview, *656but nevertheless felt that this segment of the interview yielded valuable results.
Dr. DiGiacomo was of the view that, the interview was well done, but conceded that defendant’s apparent ego control during the second half of the interview was problematic. However, Dr. DiGiacomo interpreted the altered nature of the second half of the interview as partially a function of defendant “shutting down” after the topic of Stacy Elizardo was introduced, and stated that this represented a form of defense that in itself inclined him to believe that defendant had experienced a loss of control or state of rage when he killed his victim. In contrast, Dr. Orne opined that the amytal interview did not “even have the quality of a meaningful amytal interview,” and referred to numerous indicies of defendant’s self-consciousness, ego control and awareness of his environment. He also testified that extensive use of leading questions further compromised this interview by raising the spectre of suggestibility, and by imposing a structure that both prevented a free flow of information and also raised defendant’s level of ego control through increased interaction with Dr. Sadoff.
Dr. Sadoff acknowledged that the substantive statements yielded in an amytal interview might not be true. He also stated that without the amytal interview, he would not be able to give an opinion about defendant’s state of mind because he otherwise had an inadequate sense of defendant’s motive. Nevertheless, he stressed that defendant’s feelings about the relationship between Reynolds and Elizardo emerged in the context of psychological blocking and in such a way as to suggest that this belief was extremely meaningful to defendant. On this basis, and in the absence of any other significant motive sufficient to trigger a state of rage, Dr. Sadoff felt that the amytal examination, in conjunction with knowledge acquired through other examinations, reports, and test results, justified a finding that defendant’s perception of “prostitution” and “pimping” triggered a state of rage.
*657Obviously, there was a difference of opinion among the experts concerning the reliability of the results of the defendant’s sodium amytal interview. The difference of opinion implicates the standards for determining the admissibility of these results.
C.
Reliability is one of the conditions for the test of admissibility of expert evidence. This condition requires that the state of the art or methodology in the field is developed to the extent that the information that it yields is sufficiently reliable. State v. Kelly, 97 N.J. 178, 208 (1984); Romano v. Kimmelman, 96 N.J. 66 (1984). Reliability can be established through expert testimony about general acceptance of the scientific knowledge in the given field of science and through acceptance of such knowledge reflected in authoritative scientific publications and other writings. State v. Cavallo, 88 N.J. 508 (1982). A third way of establishing the reliability of expert evidence, in a sense a derivative of the others, is by judicial opinions that have recognized its reliability. Windmere, Inc. v. International Ins. Co., 105 N.J. 373, 377-79 (1987).
In this case, expert testimony presented at trial confirms the scientifically-accepted use of the results of properly conducted sodium amytal examinations. The issue of the reliability and admissibility of sodium amytal methodology has been the subject of considerable litigation, particularly in California. As the majority points out, other jurisdictions reject the admissibility of such information when offered literally only for the purposes of establishing the truth of the matter. Ante at 630. Although the California courts agree that statements emanating from a sodium amytal test are not reliable for truth per se, it is clear that expert opinions relying on sodium amytal results are admissible. This body of case law provides no exhaustive exegesis of the principles underlying such admissibility, but examination of these cases is nonetheless most instructive.
*658In the seminal case of People v. Jones, 52 Cal.2d 636, 343 P.2d 577 (1959), cert. den., Jones v. California, 361 U.S. 926, 80 S.Ct. 364, 4 L.Ed.2d 350 (1960), a defendant accused of murder offered to repeat his assertions of innocence while under the influence of “truth serum.” The California Supreme Court unequivocally held that the results of a sodium amytal test “are not such as to be admissible for or against the defendant because of a lack of scientific certainty about the results.” Id. 52 Cal.2d at 653-654, 343 P.2d at 588. This principle has not been overruled. See, e.g., People v. Johnson, 32 Cal.App.3d 988, 109 Cal.Rptr. 118 (1973). Nevertheless, expert opinion testimony derived in part from sodium amytal interviews has been determined to be reliable and admissible in evidence. In the recent capital-murder case of People v. Milner, 45 Cal.3d 227, 753 P.2d 669, 246 Cal.Rptr. 713 (1988), the California Supreme Court did not challenge the admission of expert opinion testimony that relied on the defendant’s statements during a sodium amytal interview as a basis for the conclusion that at the time of the murder, defendant suffered from an acute panic and anxiety reaction, and was further unable to form the specific intent to rob. Id. at 235, 753 P.2d at 674, 246 Cal.Rptr. at 718.
Information derived from sodium amytal interviews often contributes toward an expert assessment of a person’s capacity to formulate a particular culpability state. In re Nevil, 39 Cal.3d 729, 704 P.2d 1332, 217 Cal.Rptr. 841 (1985) (forensic psychiatrist used sodium amytal in conjunction with other techniques to conclude that “mixed personality disorder” contributed to inability to handle stress and incapacity to intend to kill). Such testimony has also been allowed to enable the fact-finder to assess whether a defendant’s inability to remember a killing resulted from trauma or repression. People v. Hogan, 31 Cal.3d 815, 647 P.2d 93, 183 Cal.Rptr. 817 (1982). This information was also used as probative of the ultimate issue of guilt, as the expert testified that defendant’s inability to recall the incident while under the influence of sodium amytal indicated a *659lack of repression and consequent innocence. Id. at 833-34, 647 P.2d at 103, 183 Cal.Rptr. at 827. Such expert testimony has also been admitted for assessment of a historical state of mind, with videotape and transcripts of the sodium amytal interview additionally admitted into evidence. People v. Theriot, 252 Cal.App.2d 222, 60 Cal.Rptr. 279 (1967).
In admitting such opinion testimony, the California courts are not under some misapprehension regarding the potential ability of sodium amytal interviewees to lie while under the influence of the drug. Hogan, supra, 31 Cal.3d at 833, 647 P.2d at 103, 183 Cal.Rptr. at 827; Johnson, supra, 32 Cal.App.3d at 1001, 109 Cal.Rptr. at 126. Rather, it appears that they recognize that the utility of sodium amytal examinations is not solely a function of the truth of a person’s utterances, and that expert opinion testimony, derived from such examinations in conjunction with other information obtained that does not depend wholly or primarily on the “truth” as such, can be accepted as reliable in accordance with relevant professional standards.
This experience is paralleled to some extent by our own. In State v. Hurd, 86 N.J. 525 (1981), we recognized the admissibility of hypnotically-induced evidence when hypnosis is used as a means of overcoming amnesia and restoring the memory of a witness. Although we acknowledged the numerous reasons for which hypnosis is not necessarily a procedure that yields accurate recall, reasons that are remarkably similar to those that compromise the reliability of sodium amytal, we nonetheless found that “hypnosis can be considered reasonably reliable if it is able to yield recollections as accurate as those of an ordinary witness, which likewise are often historically inaccurate.” Id. at 538.
In addition, our Rules of Evidence invite reasonable leeway in enabling an expert to express the basis of his opinion. Evidence Rule 56(2) states that:
A witness qualified pursuant to Rule 19 as an expert by knowledge, skill, experience, training or education may testify in the form of opinions or otherwise as to matters requiring scientific, technical or other specialized *660knowledge if such testimony will assist the trier of fact to understand the evidence or determine a fact in issue. The facts or data in the particular case upon which an expert bases an opinion or inference may be those perceived by or made known to him at or before the hearing. If of a type reasonably relied upon by experts in the particular field in forming opinions or inferences upon the subject, the facts or data need not be admissible in evidence.
This formulation of the rule was intended to “allow more latitude in the admission of expert opinion testimony” without being inconsistent with the “spirit” of the old rule. See Biunno, Current N.J. Rules of Evidence, Comment 7 to Evid.R. 56(2). The rule makes it clear that an expert opinion may be based on “data relied upon by the expert which is not necessarily admissible in evidence but which is the type of data normally relied upon by experts in forming opinions on the same subject.” Ibid. The relative breadth of this standard in comparison with the prior limitation of expert opinions to those that the trial court found to be “based primarily on facts, data or other expert opinion established by evidence at the trial” demonstrates a marked shift in the underlying assumptions that the Court should bring to bear on the admissibility problem presented in this case. Reflecting this change in attitude, courts are admonished to accord some weight and deference to the experience and professional integrity of the expert whose opinion is being offered, particularly with respect to psychiatric opinion that necessarily is derived from the examination and statements of patients. See, e.g., State v. D.R., 109 N.J. 348 (1988); Saunderlin v. E.I. DuPont Co., 102 N.J. 402 (1986).
In sum, several considerations are relevant in applying the standards governing the reliability of expert testimony in this case. There is general acceptance of the scientific knowledge within the scientific community as reflected in the opinion of experts. There is considerable decisional law that confirms the acceptability and use of such knowledge in the scientific community in both practice and for evidentiary purposes in litigated cases. Our basic evidentiary rule governing the admissibility of expert opinion counsels admissibility of the results of professionally acceptable procedures that form the basis of an ex*661pert’s opinion. Our own judicial precedent involving psychiatric opinion testimony has endorsed the scientific acceptability of knowledge acquired through comparable techniques and its reliability for evidentiary purposes.
D.
It is important to note that in ruling that Dr. Sadoff’s proffered opinion evidence was inadmissible, the trial court squarely predicated exclusion on the apparent unreliability of this particular examination as well as the general unreliability of sodium amytal procedures. It clearly erred to the extent it allowed itself to be influenced by the perception of the general unreliability of such testing, appearing to have been influenced by the uncritical application of State v. Sinnott, 24 N.J. 408 (1957), to the facts of this case.2 Here, however, all of the experts expressed the view that such examinations and the results of those examinations were generally accepted within the scientific community for particular kinds of psychiatric evaluations.
The trial court’s evaluation of this sodium amytal test was rooted in the assumption that the sole purpose and only result of this examination was to gather statements intended to stand for the truth of the matter asserted. The trial court, however, clearly undervalued Dr. Sadoff's experience and misperceived both the purpose of Dr. Sadoff in conducting the amytal exami*662nation and his use of other sources of information in arriving at his expert opinion concerning defendant’s state of mind.
Although Dr. Orne described Dr. Sadoff’s purpose as an attempt to ascertain the veracity of competing versions of defendant’s motive, an ascription accepted by both the trial court and now the majority, Dr. Sadoff actually used sodium amytal as a diagnostic tool in determining whether defendant’s actions arose from Vietnam delayed stress syndrome, although he also was open to the possibility that defendant might further disclose his motives or state of mind at the time of the crime.3 Further, Dr. Sadoff’s opinion was based on analysis of other sources of information in addition to the sodium amytal interview.4 Finally, as indicated by the expert testimony adduced at the Rule 8 hearing, the substantive comments elicited from an interviewee are not the only resources drawn on; an interviewee’s manner, style, or inability to respond to particular topics are among the useful clues that a psychiatrist can draw on in coming to an opinion about an interviewee’s condition or state *663of mind.5 In coming to their conclusions, psychiatrists take this information in conjunction with other sources, including additional interviews and tests, and apply their analytic expertise to the entire range of materials. Thus, as indicated by testimony elicited at the Rule 8 hearing, sodium amytal interviews in general, and this one in particular, can yield data that is useful in ways entirely independent of the literal truthfulness of what the interviewee actually says. It is thus clear that Dr. Sadoff reached his judgment incrementally, basing it on defendant’s statements as analyzed in conjunction with other information derived from the amytal examination and sources of information entirely independent of the examination.6
The inability to recognize the independent value of this expert process of interpretation and analysis is shown by the trial court’s “but for” analysis of Dr. Sadoff’s testimony. Because Dr. Sadoff testified that prior to ordering the sodium amytal interview he did not feel that his access to defendant and other test results gave him enough information to arrive at an opinion on defendant’s state of mind, the trial court determined that Dr. Sadoff’s proffered testimony was flawed due to the “but for” character of the amytal evidence. This analysis *664implies that the amytal interview is the sole source of Dr. Sadoff s opinion, and that he is in effect parroting defendant’s statement.
Such analysis, however, undervalues both the role of Dr. Sadoff’s expertise and his use of other sources of information, in addition to the literal meaning of defendant’s statement, in arriving at his expert opinion. Dr. Sadoff made his judgment based on defendant’s statement as analyzed in conjunction with other information derived from the amytal interview and sources of information entirely independent of the interview. It is therefore incorrect to postulate that Dr. Sadoff’s unwillingness to state an expert opinion without the sodium amytal data is the same as making a judgment on the sole basis of the sodium amytal interview. This latter principle would be exemplified by a situation in which an expert proffers an opinion based only on a defendant’s statement of guilt or innocence given while under the influence of sodium amytal. It is this kind of usage of sodium amytal, redolent of discredited notions of “truth serum,” that is unacceptable. This example, however, bears little resemblance to the situation presented in defendant’s case.
In its acceptance of the trial court’s analysis and determination of this issue, the Court thus neglects to consider the extent to which the knowledge derived from professionally-conducted sodium amytal examinations is accepted for purposes of diagnosis and treatment and is acknowledged to be scientifically reliable. These considerations conform to our standards for admissibility of such knowledge by experts in the field. Here, defendant does not argue that the knowledge derived from his examination is to be admitted for a purpose that is inconsistent with its accepted use in practice; he does not contend that the substantive utterance of his motive is inherently true through the magic of sodium amytal. Rather, defendant’s expert witnesses have stated that the knowledge gleaned from the examination is probative of defendant’s state of mind in the context in which sodium amytal interviews are generally used; they are *665a useful diagnostic device because they provide a tremendous amount of information about an interviewee’s subconscious mind.
A brief review of relevant evidence confirms that Dr. Sadoff’s proffered opinion should have been understood in this context. Throughout the guilt phase, defendant maintained that the killing was committed in a state of rage. In turn, the State argued that the evidence demonstrated that defendant had a monetary motive for the killing, indicating that defendant’s actions were premeditated. It is therefore fully understandable that Dr. Sadoff resorted to sodium amytal to clarify and determine defendant’s probable state of mind. He was primarily interested in whether defendant might abreact or otherwise affiliate with his Vietnam experiences; a positive diagnosis of delayed stress syndrome would have increased the likelihood that post-Vietnam delayed stress syndrome provided the reason or motive for his actions and insight into his state of mind. Defendant’s failure to enlarge in any way on his Vietnam experiences during the amytal interview was highly significant. Dr. Sadoff used this result to rule out the role of a Vietnam flashback, and even Dr. Orne stated that this made it “more likely” than not that Vietnam delayed stress syndrome was not responsible for triggering defendant’s actions.
This elimination of delayed stress syndrome exemplifies the legitimate professional diagnostic use of sodium amytal, but the elimination of delayed stress syndrome left unanswered the question of defendant’s state of mind; premeditation and a monetary motive could not explain the frenzied type of rage that accompanied the killings. As already shown, this rage was attributable to sexual anger and jealousy, a conclusion derived incrementally from a number of sources, including — importantly and perhaps necessarily, but not exclusively — the amytal examination. It is unfair and inaccurate to conclude, as did the trial court, that Dr. Sadoff was of the opinion that the defendant acted with the belief that Stacey was engaged in prostitution simply because the defendant said this during the sodium *666amytal interview. Rather, it seems in light of the entire record that Dr. Sadoff’s opinion that defendant acted in a rage involving sexual jealousy was based on the fact that a monetary motive was insubstantial, that evidence of delayed stress was equivocal, that defendant had continuing strong sexual feelings for Stacey, and that he ineffectively attempted to deny feelings of jealousy and used the explanation of prostitution as an excuse or reason for his anger. Thus, what was significant to Dr. Sadoff was not defendant’s belief that Stacey was engaged in prostitution or whether defendant truly believed this, but rather the fact of defendant’s rage actuated by feelings of sexual attraction and jealousy.
Moreover, the reliability and probative worth of this information was indirectly corroborated. Dr. Cooke concluded that defendant had significant potential for rage or “loss of control” due to a cyclothymic personality disorder. He relied on physical evidence at the scene of the crime, defendant’s statements to him, and the results of diagnostic tests. Ante at 608-609. Dr. Sadoff also relied on eyewitness reports, non-sodium amytal examinations, and the results of Dr. Cooke’s testing; he also used the sodium amytal examination. The court’s rejection of Dr. Sadoff’s evaluation of defendant’s state of mind seems hypertechnical in light of its acceptance of Dr. Cooke’s evaluation, particularly inasmuch as Dr. Sadoff was provided with and used Dr. Cooke’s reports and test results, and even went one step further by turning to sodium amytal as an additional diagnostic tool.
The result reached by the Court cannot be easily reconciled with our approach and decision in State v. Hurd, in which Dr. Orne coincidentally testified as the proponent of hypnotically-induced statements of a witness. He expressed the opinion that hypnosis would often be reasonably reliable in reviving normal recall in cases of traumatic neurosis. He also acknowledged that the likelihood of accuracy diminished when hypnosis is used to “refresh a witness’ memory concerning details when there may be no recollection at all, to ‘verify’ one of several *667conflicting accounts given by a witness,” or when a witness had “a discernible motivation for not remembering or for ‘recalling’ a particular version of the events.” Hurd, supra, 86 N.J. at 544. This testimony parallels many of the points made by Dr. Orne in the Rule 8 hearing regarding defendant’s sodium amytal examination. Further, Dr. Orne explicitly equated the effects of hypnosis with those of sodium amytal; he even stated at one point that “[a]mytal is not any more than hypnosis going to tell you the answer to what is true.” Nonetheless, we ruled in Hurd that an utterance similarly derived through hypnosis, an alternative form of narcoanalysis, can be presented to the jury for evaluation of credibility.
In sum, there was sufficient basis in the record to require the trial court to admit expert testimony relating to the results of the sodium-amytal examination of the defendant. While evaluation and probative worth of that testimony might be the subject of differences of opinion, such differences did not impugn the admissibility of evidence that should have been presented for the jury’s consideration and assessment of the weight and credit to be accorded to it. This applies as well to the asserted deficiencies in the specific amytal examination identified in the Rule 8 hearing, such as the use of leading questions and the significance, if any, of the fact that defendant apparently did not experience an abreaction during the interview. Each of these considerations would bear on the credibility of the defendant and the reliability of any assertion of truth within the interview.
The presentation of such evidence subject to full cross-examination and rebuttal, along with a general jury charge concerning the jury’s overall responsibility for determining credibility and the assessment and application of expert testimony, and a specific charge concerning the possible unreliability of facts learned by an expert from a subject testifying under the influence of sodium amytal, would properly serve the need to balance probativeness against prejudice. These considerations *668strongly dictate the admissibility of the expert’s opinion during the guilt phase of this case.
E.
The exclusion of Dr. Sadoff’s testimony was highly prejudicial. As noted, defendant’s state of mind at the time of the murders was a major issue that confronted the jury in determining defendant’s guilt. Accordingly, each side devoted substantial attention to the issue of defendant’s underlying motive. The prosecutor stressed the theme of premeditation and the monetary motive which had been expressed by defendant several times, particularly during the early stages of the investigation. In turn, the defense presented the theme of defendant’s sexual jealousy.
The ability of the defense to present this case to the jury was compromised, however, by the different accounts of the killing that defendant gave over the course of the investigation and the trial. During the initial police interview, defendant claimed that the killer was a mysterious third party. During a subsequent interview, defendant confessed to the killing and cited an overdue debt as his motive; defendant also adhered to this line during an interview with a parole officer. In his initial interview with Dr. Cooke, defendant introduced the theme of the Vietnam flashback. Finally, from the time of the sodium amytal interview, defendant introduced elements of the theme of sexual jealousy. This theme, however, was never presented in a coherent or complete manner, even during defendant’s own testimony at trial.
This theme would have become much clearer and coherent if Dr. Sadoff had been allowed to testify concerning his opinion of defendant’s state of mind based in part on the results of the sodium amytal examination. This opinion was significant not only for its probative worth as a plausible version of what was going on inside defendant’s head at the time of the killing; in addition, Dr. Sadoff’s expert testimony would have provided *669insight into the reasons for defendant’s presentation of conflicting stories. This case presents a classic example of a situation in which there is an acute need for the knowledge of an expert to assist a jury in its search for the truth. See State v. Kelly, supra, 97 N.J. 178.
Chronological examination of evidence presented to the jury at trial shows the potential of this testimony as a guide for the jury. First, the theme of intense emotional preoccupation with Elizardo’s sexual life surfaces during defendant’s second statement to the police; his statements at that time reflect a curious mixture of bravado and pain.7
During a subsequent interview with Dr. Cooke, defendant gave an account of the incident at Elizardo’s house prior to the killing that sounded this same theme, including the feelings of being insulted and misused.8
*670Defendant’s next major statement was made to Dr. Sadoff during the sodium amytal examination. The jury, however, never heard of defendant’s first explicit and illuminating statement of his perception of the Elizardo-Reynolds relationship or of Dr. Sadoff’s explanation for the meaning of that statement within the context of defendant’s psyche.
Shortly before trial, Dri Cooke again interviewed defendant, who characterized Elizardo's sexual acts as “prostitution.” According to Dr. Cooke, this appeared to be a rationale by defendant to mask his strong feelings of jealousy, feelings which he perceived as an indication of weakness.9
*671Finally, at trial, defendant elaborated on the theme of his affection for Elizardo and consequent dislike for Reynolds. However, this presentation was never coherent; it is clear that defendant’s own feelings toward Elizardo were still highly charged and unresolved. For example, in his sodium amytal examination, defendant articulated his belief that Reynolds was pimping Elizardo in exchange for money and drugs. The jury was presented with toxicology reports indicating that while Reynolds was drug-free, Elizardo tested positive for amphetamine and methamphetamine. Nevertheless, defendant rather emphatically refused to say anything that he considered derogatory about Stacy.10
It is thus apparent that defendant’s feelings may have been mixed or confused, and his expression of these feelings may often have exhibited a bizarre ambivalence, but it is nonetheless clear that these feelings were very intense, perhaps enough so to trigger the state of rage that was at issue.
However, by being denied access to Dr. Sadoff’s expert testimony or knowledge of defendant’s crucial first statements regarding his perception of the Elizardo-Reynolds relationship, the jury was deprived of evidence that could help to explain these inconsistencies and unify the disparate elements of defendant’s stories. The phenomena of blocking and repression, recognized by all of the experts as surmountable or approachable through the professional use of sodium amytal and further elaborated on by Drs. Sadoff and DiGiacomo in the context of *672defendant’s examination, were probative of an understanding of defendant’s multiple accounts of his motivation and state of mind and on issues of credibility. Defendant’s credibility could only profit from revelation of an expert opinion that could serve to explain defendant’s actions, both during and after the killings, in light of his psychological problems. Further, had the jury been alerted to the timing of the sodium amytal examination relative to defendant’s other statements, the presentation of sexual jealousy and rage as defendant’s motive would have been much more coherent.
This context for the potential role of Dr. Sadoff’s expert testimony thus demonstrates the substantial probative worth of the evidence that he sought to offer. The deprivation to the defense by the erroneous exclusion of this evidence was gravely prejudicial and clearly requires reversal of defendant’s murder convictions.
III.
Dr. Sadoff’s proffered opinion testimony should unquestionably have been admitted during the penalty phase. This conclusion is compelled not only by the ultimate purpose of the penalty phase and the spirit that animates both our capital-punishment statutory scheme and our decision in State v. Davis, 96 N.J. 611 (1984), but also by the special probative worth of such testimony in determining the ultimate issue in the sentencing trial of Daryl Pitts — whether he should live or die.
Our capital-punishment sentencing scheme contemplates that a defendant convicted of murder and eligible for a death sentence will be able to present evidence and argument commensurate with the sanction sought by the State. Accordingly, the statute provides standards for the admissibility of evidence presented by defendant in support of mitigating factors that are less stringent than those applied in other criminal proceedings. N.J.S.A. 2C:ll-3c(2)(b). Further, defendants face a burden of proof in establishing mitigating factors that is less *673demanding than the burden faced by the State in establishing aggravating factors. N.J.S.A. 2C:ll-3c(2)(a). We insist that for a sentence of death to issue, the fact-finder must determine beyond a reasonable doubt that any aggravating factors found to exist outweigh any mitigating factors. State v. Biegenwald, 106 N.J. 13, 53 (1987). This structure is intended to give defendants the fullest opportunity to argue for their lives.
Consistent with this policy is our determination that fact-finders not be denied access to information that would have a mitigating effect through the elicitation of mercy or sympathy. State v. Ramseur, supra, 106 N.J. at 299. Indeed, the Court does not allow a defendant to prevent his attorneys from presenting mitigating evidence because such action would “withhold[] from the trier of fact potentially crucial information” that has important implications for the constitutionality of our death penalty statute. State v. Koedatich, 112 N.J. 225, 331-32 (citation omitted), cert. den., Koedatich v. New Jersey, — U.S. -, 109 S.Ct. 813, 102 L.Ed.2d 803 (1989). Although the Court does not find any constitutional right to have a jury evaluate evidence in light of an independent charge mandating consideration of mercy or sympathy, it perhaps does so with confidence that the scheme of mitigating factors will serve as an appropriate vehicle for the inspiration of such feelings. Ante at 598. In the exercise of our supervisory jurisdiction over criminal trials, we permit defendants to exercise the common-law right of allocution, allowing them to express directly to the jury that they are individuals “capable of feeling and expressing remorse and of demonstrating some measure of hope for the future.” State v. Zola, 112 N.J. 384, 430 (1988) (citation omitted). These characteristics exemplify the Court’s acknowledgment of the “highly discretionary nature of the jury’s duty to balance the statutory aggravating and mitigating factors” in the sentencing phase of a capital case. State v. Bey (I), 112 N.J. 45, 95 (1988).
Examination of the sentencing philosophy and methodology of our capital-murder statute reveals that the defendant’s mo*674tive is the critical and salient consideration in choosing between life imprisonment or the ultimate sanction of death. This emphasis on motive as an index of appropriate punishment is reflected by many of the statute’s aggravating factors. Murders committed in exchange for the receipt of anything of pecuniary value, N.J.S.A. 2C:ll-3c(4)(d), committed for the purpose of escaping detection or confinement, NJ.S.A. 2C:11-3c(4)(f), while engaged in other criminal activities, N.J.S.A. 2C:ll-3c(4)(g), or because of the victim’s status as a public servant, N.J.S.A. 2C:ll-3(c)(4)(h), are considered so reprehensible as to justify the death penalty because society is particularly repulsed by the idea that such motives can lead to murder. Further, our interpretation of aggravating factor N.J.S.A. 2C:ll-3c(4)(c) essentially defines “depravity” as a murder committed with the absence of motive. Gerald, 113 N.J. at 66; Ramseur, supra, 106 N.J. at 211.
The importance of motive is also discernible throughout the range of mitigating factors. N.J.S.A. 2C:ll-3c(5)(a), (b), and (e) consider whether the defendant was under the influence of extreme mental or emotional disturbance insufficient to constitute a defense to prosecution; whether the victim solicited, participated in, or consented to conduct resulting in death; and whether the defendant was under unusual and substantial duress insufficient to constitute a defense to prosecution. Further, the “catch-all” mitigating factor, c(5)(h), could certainly accommodate any motive that might demonstrate an ameliorative quality. In short, the penalty phase of a capital case is a wide-ranging investigation not only of a defendant’s character, but also of his or her motives. Thus, the determination of a defendant’s motive for murder, a determination that lies close beneath the surface of a guilt phase proceeding but is never directly addressed as an element of murder, is at the heart of a penalty phase proceeding in a capital case.
The central role of motive in the penalty phase has significant ramifications for the admissibility question posed in this case. In its extensive quotation of our decision in Davis and acknowl*675edgement of N.J.S.A. 2C:ll-3c(2)(b), the Court is cognizant of, and indeed endorses, the principle of broad admissibility of evidence offered to establish the existence of mitigating factors. Ante at 619-22. The sticking point, however, is that although the Court recognizes that Davis effectively relaxes the standards of penalty-phase admissibility, the Court maintains that the unreliability of a sodium amytal test result, because it arguably could be used to establish the truth of a defendant’s belief, is a substantia] enough consideration in this case to preclude admission of the testimony proffered by Dr. Sadoff. Ante at 631-34.
I strenuously disagree. It is virtually undeniable that admission of this evidence is not only consistent with the policy goals that underlie Davis, but also with the actual language of that decision. In Davis, the Court stated that a trial court “must retain discretion to exclude ... evidence, in whole or in part, if its probative value is substantially outweighed by its unfounded or speculative character and the risk of confusion of the substantial issues.” Davis, supra, 96 N.J. at 623-24. Here, since resolution of defendant’s motive is the central issue to be decided in this penalty phase, the essential test to be applied is the balance between the probativeness and the speculativeness or groundlessness of the proffered evidence.
The case of Barefoot v. Estelle, 463 U.S. 880, 103 S.Ct. 3383, 77 L.Ed.2d 1090 (1983), provides a benchmark for the permissible limits of speculative expert psychological evidence in the penalty phase of a capital case. In Barefoot, the Supreme Court upheld the admissibility of psychiatric testimony concerning a capital defendant’s future dangerousness offered pursuant to specific provision in the Texas death-penalty statute that treated future dangerousness as an aggravating factor. Although the psychiatrists had not even conducted a personal interview with the defendant, the Court stated that this evidence should be presented to the jury where the benefits of cross-examination and submission of contrary evidence by the opposing party would justify trust in the ability of the adver*676sary process “to sort out the reliable from the unreliable evidence and opinion about future dangerousness.” Id. at 901, 103 S.Ct. at 3398, 77 L.Ed.2d at 1109.
It is evident that Dr. Sadoff s testimony does not engender this degree of speculativeness. Nor can his testimony be dismissed as unfounded. Even if the substance of defendant’s statement was not taken at face value, it cannot be ignored that Dr. Sadoff’s opinion relied on other sources of information derived from and in addition to the sodium amytal interview.
In comparison, the probative value of this material is obvious. “Probative value” has been described as “the tendency of evidence to establish the proposition that it is offered to prove.” McCormick, Evidence § 185 at 541 (E. Cleary 3d ed. 1984). Here, the probativeness of Dr. Sadoff’s testimony is demonstrated not only by the extent to which it provides an answer to the immediate and central question of defendant’s motive, but its power to explain why defendant obscured any understanding of his situation through his initial furnishing of other motives. Indeed, by demonstrating defendant's own inability to come to grips with his intense feelings for Stacy Elizardo, Dr. Sadoff’s expert testimony inclusive of the amytal examination provides exactly the sort of clue to defendant’s character and motives that our statutory scheme is designed to place before a penalty-phase jury.
The Court nevertheless holds that this evidence was properly excluded. In doing so, it suggests that any harm to defendant’s cause was self-inflicted inasmuch as defendant was presented with the opportunity to have Dr. Sadoff testify on the basis of evidence already in the record, particularly defendant’s own trial testimony that his accusation of Reynolds as pimping for Elizardo precipitated a shoving match that escalated into the fatal attacks. Ante at 634. This conclusion, however, is fundamentally flawed in that such an offer had the effect of eviscerating defendant’s evidence. The essence of Dr. Sadoff’s particular insight in this case arises from the applica*677tion of his expertise to the information he personally gleaned from the defendant, including, of course, all of the non-literal sources that support his testimony. If the defendant miscalculated in terms of a trial tactic, namely, the withdrawal of Dr. Sadoff s testimony, such tactical error was necessitated by the trial court’s own erroneous ruling. The difficulty of this issue, perhaps indicated by the length of this Court’s discussion, might explain, if not justify, the trial court’s exclusion of this evidence at the guilt phase. However, the trial court clearly erred when it extended this exclusion to the penalty phase; indeed, the trial court’s statement that “it doesn’t make any difference whether its the penalty phase or the guilt phase” is most disturbing. It demonstrates a failure to understand those sensitive and unique aspects peculiar to penalty phase deliberations that are established by statute and recognized by our case law. In this light, it is disingenuous to attribute the compromise of defendant’s presentation solely to his own strategic trial decisions.
Finally, we must consider the delicate balancing process that juries engage in during a capital-penalty proceeding. Juries are charged not only with the duty to determine the existence of statutory factors, but also to assign a quantum of weight for balancing purposes. It follows that every shred of relevant evidence is precious to a defendant seeking to save his or her life. In light of this balancing requirement, one is confounded by the suggestion of the Court that admission of this evidence is unnecessary because the jury found that the defendant was under the influence of extreme mental or emotional disturbance insufficient to constitute a defense to prosecution, a mitigating factor under c(5)(a). One is further perplexed by the Court’s cryptic acknowledgement that the exclusion of Dr. Sadoff’s testimony “may” have affected the balancing of statutory factors. Ante at 631. Recent legal scholarship has begun to focus on the limited utility of “reliability” analysis in assessing capital sentencing decisions that primarily involve the weighing of values rather than the determination of facts. See, e.g., *678Berger, The Supreme Court and Defense Counsel: Old Roads, New Paths — A Dead End?, 86 Colum.L.Rev. 9, nn. 443, 470 (1986); Goodpaster, The Adversary System, Advocacy, and Effective Assistance of Counsel in Criminal Cases, 14 N.Y.U.Rev. of L. and Social Change 59, 83-85 (1986); Note, Ineffective Assistance of Counsel at Capital Sentencing, 39 Stan.L.Rev. 461 (1987); cf. Ake v. Oklahoma, 470 U.S. 68, 87, 105 S.Ct. 1087, 1098, 84 L.Ed.2d 53, 68-69 (1985) (Burger, C.J., concurring) (finality of sentence in capital cases warrants protections that may or may not be required in other cases). In a context where the nature, quantum and quality of subjective evidence is exceedingly critical, it is untenable to believe that additional evidence that could increase the weight of mitigating circumstances is “unnecessary” to a defendant seeking to have a jury spare his life.
Accordingly, given the broad policy dictates implicit in the statute and explicit in our case law, I cannot agree with the Court’s decision to exclude the expert testimony proffered by Dr. Sadoff from consideration by the jury during the penalty phase of this case. Because of these policies and in light of the ultimate gravity of the decision faced by a penalty-phase jury, each of the arguments and considerations that may point toward the admission of evidence during the guilt phase applies with irresistible force to the penalty phase. The Court’s determination to the contrary is, in my opinion, untenable and unjust.
IV.
In conclusion, the defendant’s murder convictions must be reversed. He was denied the right to have the jury consider the evidence in light of a charge based on non-capital or ordinary murder, as clearly mandated by our Gerald decision.
The defendant was, moreover, critically prejudiced by the exclusion of the expert opinion of Dr. Sadoff concerning defendant’s state of mind and motive, which opinion was derived from a scientifically acceptable procedure widely used within *679the scientific community and undertaken in accordance with professional standards by an eminently qualified expert. In light of the admittedly different standards applicable to penalty-phase admissibility, the exclusion of this evidence from consideration by the sentencing jury is indefensible. The error of exclusion becomes even less defensible with the realization that all aspects of the facts underlying the proffered opinion, as well as ultimate conclusions, would be subject to complete cross-examination and rebuttal, serving to enhance the jury’s ability to evaluate evidence and assess credibility.
The prejudicial exclusion of this evidence warrants reversal of defendant’s murder convictions, impugns the imposition of the death sentence, and assuredly should not be duplicated in any resentencing trial.
Accordingly, I dissent.
For affirmance in part and reversal in part —Chief Justice WILENTZ and Justices STEIN, CLIFFORD, POLLOCK, O'HERN, and GARIBALDI — 6. Dissenting —Justice HANDLER — 1.The crime of serious-bodily-injury murder, committed either purposefully or knowingly, is a lesser-included offense of purposeful/knowing capital murder because it differs from the latter only in that the defendant contemplated a less serious result or harm than death. N.J.S.A. 2C:l-8(d)(3).
In Sinnott, and in the successor case of State v. Levitt, 36 N.J. 266 (1961), the underlying issue was the admissibility of expert evidence, based on a sodium amytal interview, that was intended to show that defendant did not have a propensity or deviational trait indicative of a tendency to commit various sex-related offenses. In excluding such evidence, the Sinnott Court was greatly influenced by the purpose of the proffer. The Court focused not only on case law prohibiting the admission of testimony elicited from a person while under the influence of sodium amytal, but also analogized the proffered testimony to evidence of good character intended to prove that defendant did not commit the crime. Sinnott, supra, 24 N.J. at 420-21. In the present case, however, the evidence is proffered not to establish that defendant did not kill, but to demonstrate his state of mind at the time of the killing.
At the Rule 8 hearing, Dr. Sadoff testified as follows:
I had no understanding as to why he killed Paul because he wasn’t able to tell me. He said they got into an altercation, but he didn’t say about what. It was never very clear to me about what would have stimulated in Darryl Pitts sufficient rage to kill this man, and the reasons given seem superficial to me and were not sufficient for that type of rage.
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I had an opinion about the Viet Nam stress syndrome, and I had no other understanding as to why these two people were killed, and I said if we do the sodium amythal [sic] we can either confirm the Viet Nam stress syndrome idea or maybe something else will emerge. And what came out was this story that I had not had before which seemed to me to be consistent with the type of rage that would be necessary for homicide under those circumstances.
During the Rule 8 hearing, Dr. Sadoff stated explicitly that the “sodium amytal report is not just based on sodium amytal, it’s based on everything. I don't just base any reports on just sodium amytal, it’s [sic] based on all the other information that I have." Here, the extent of such additional sources was substantial. Supra at 654.
As Dr. Sadoff testified at the Rule 8 hearing:
[M]y interpretation of the test and the reliability of that test [of defendant] under those conditions at that time, and my interpretation is that it came after a period of blocking or resistance that indicates that it’s something that happened dredged up from the bottom and had been suppressed or repressed there and was meaningful to him.
The trial court, moreover, was not justified in placing such dominant reliance on Dr. Orne’s testimony concerning the usefulness of this examination; the record clearly reflects that although his credentials as a psychiatrist were impeccable, he was much less experienced in the use of sodium amytal than Drs. Sadoff and DiGiacomo. Dr. Sadoff testified that over the course of his career he had administered about 150 sodium amytal interviews; Dr. DiGiacomo stated that he had administered approximately 4,000. Dr. Orne, however, claimed to have conducted "maybe 20”. It appears from Dr. Orne's testimony that one of the primary bases for his expert opinion is analogy to his expertise in the use of hypnosis.
This exchange occurred:
Q [H]ave you ever been intimate with [Stacy]?
A Have I?
Q Yes.
A Yeah.
Q Do you recall on how many occasions?
A Not that often because she gets laid as much as she wants and I guess it’s her — she didn’t need to get laid that much or she wants to get laid by the person she wants to. I don’t know, really.
Q Well, when you went to the apartment, now it's the 23rd, on the 22nd which was yesterday, did you have any jealously of the fact that she was with another man?
A No. Because I became accustomed to that because I’ve been over there so many times, men come and go out of there. I figure she was running a fucking whorehouse.
Dr. Cooke testified:
What he told me really starts two days before the offense itself. And on that day there was a situation in which he was at Paul’s [actually, Stacy’s] house, Stacy was there, and he preceived [sic] himself as having helped Paul and Stacy in that situation by helping to get someone [Vincent Della Polla] out of the apartment that they did not want there.
So the important thing that I felt from a psychological point of view about that incident was that he indicated a feeling that he had helped Stacy *670and Paul, which is important because it ties in with his feeling and the personality dynamics.
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he is not very good at getting these feelings out and you have to pull and talk about it, but that he felt that because of the incident two days before where he had helped he felt at that point he was being used, that Stacy didn’t want to come out and talk to him, Paul was arguing with him, that he had served his purpose for them and they were just using him and dumping him, so he was upset about that.
He also indicated ... that Paul was belittling him, mocking him and insulting him____
Dr.- Cooke testified that:
[Defendant] indicated that Paul implied, did not say so in so many words, but implied that Stacy was engaging in sexual relations in order to get drugs and he said, he used the term “prostitution.” He said that that was the first he had heard or recognized that possibility.
I questioned him specifically about why he told the police that he went to the apartment because he owed money and also why he came up with [such] a specific figure as $700.00. He indicated to me that [Reynolds] did not owe him money, that the $700.00 figure was, had something to do with what his wife told him she needed to pay some bills and that he told the police that for two reasons. One, that he did not want to seem involved with drugs, the other, and as we went over this, this seemed to emerge as the primary reason, he used the term, “emotional cripple. ” He did not want the police to think of him as somebody who couldn't control himself and killed two people because of emotional problems, but, rather, wanted to give them an explanation that didn’t label himself that way, an explanation that he went there because they owed him money.
[Emphasis added.]
The following exchange occurred during cross-examination of defendant:
Q And you believe it's the macho thing to tell this jury that you killed her because she was prostituting herself and that Reynolds was pimping her, is that what you want this jury to believe?
A I want the jury to believe that I didn't have the intentional thought to harm these people.
Q My question, sir, do you really want this jury to believe, not only that you killed her, but you killed her because Paul Reynolds was pimping her as a prostitute, is that what you want this juty to believe?
A I don’t want them to believe anything like that about Stacy.