¶1concurring:
¶2Although I can concur in the result reached by our brother Manoukian, I must respectfully note my belief that the above opinion lacks any acceptable rationale concerning the issue of expert testimony.
¶3The opinion states that “appellant simply failed to establish a viable foundation for the elicitation of the desired opinion,” despite the fact that appellant’s proffered expert has earned both master’s and Ph.D. degrees in clinical psychology, has extensive experience in that field, and has often been recognized by Nevada courts as an “expert” for purposes of giving testimony. Two reasons are articulated for this holding, i.e., that there is no showing [1] “whether this type of expert testimony is within a recognized field of expertise,” and [2] “but moreover respecting the witness’ competency.”
¶41. The discourse following this preliminary statement does not even attempt to support the first ground — which is not surprising. Here, appellant’s expert was prepared to cite and discuss scientific literature concerning the expertise which has been developed through scientific study of witnesses’ capacity to report their observations with accuracy. Moreover, legal research discloses no case excluding testimony of this kind on the ground that it is outside a recognized field of expertise.
¶52. The above opinion’s only attempt to justify the second ground mentioned, so far as I can see, is the statement: “There is no express showing that he [the expert] would have addressed himself to the testimony of the victim with reference to Speake’s retention and recollection capacity, the effect of *151stress, if any, on Speake’s power of perception, or other relevant considerations. Rather, he would have testified about the unreliability of eyewitness accounts in general.” Thus, in essence, the above opinion suggests that it somehow is improper to develop general testimony in an area of expert knowledge, and rely upon other evidence to relate such testimony to the case. This is contrary to both the evidence code and previous Nevada authority. See NRS 50.275; 50.285(1); Southern Pacific Co. v. Watkins, 83 Nev. 471, 435 P.2d 498 (1967); Wallace v. State, 84 Nev. 603 , 447 P.2d 30 (1968); cf. Ginnis v. Mapes Hotel Corp., 86 Nev. 408, 470 P.2d 135 (1970); Shoshone Coca-Cola v. Dolinski, 82 Nev. 439, 420 P.2d 855 (1966); L.A. & S.L.R. Co. v. Umbaugh, 61 Nev. 214, 123 P.2d 244 (1942).
¶63. Following such discourse, which supports neither of the legal propositions first given as “grounds” for its holding, the. above opinion proceeds into a discussion unrelated to either. Some of that discourse is patently unsound. For example, I suggest this court can hardly justify excluding expert testimony by asserting that “defense counsel had the responsibility, which he ably accepted, of cross-examining Speake.” Defense counsel had no “responsibility” to cross-examine Speake. His responsibility was to defend appellant in the best manner legally available, and, if counsel’s choices included the use of expert testimony, then counsel was free to use that method of defense exclusively, or to use it in conjunction with cross-examination. Moreover, if the court improperly forced counsel to proceed by cross-examination only, then we can hardly defend the court’s error, by noting that counsel “ably accepted” the burden of attempting to impeach the witnesses solely by cross-examination. What kind of rule should our bench and bar elicit from such a commentary? I suggest that the only rule which can be educed — i.e., that trial courts may reject expert testimony with impunity, provided counsel unsuccessfully attempts to get the same information before the jury by cross-examination or by some other artifice — is patently unsound.
¶7The above opinion also vaguely asserts that, had the trial court permitted appellant’s expert to testify, “there existed a substantial risk that the potential persuasive appearance of Hess would have had a greater influence on the jury than the evidence presented at trial, thereby interfering with the province of the jury.”
¶8In Nevada, experts may testify as to ultimate issues of fact, even though such testimony traditionally invaded the province of the jury. See NRS 50.295; Southern Pacific, cited above, 83 Nev. at 488, 435 P.2d at 509. If the court intends to *152carve out an exception to this general rule, then I believe we must likewise delineate the rationale for our decision. This would prevent confusion and erroneous extension of our holding beyond its factual setting.
¶94. After reading of the authorities dealing with the specific issues before us, I believe authorities exist to support affirmance, some based on vague rationale, and some with better logical focus. For example, some courts have said experts may not impeach eyewitness accounts because cross-examination is a more efficient method for testing credibility. Sec United States v. Amaral, 488 F.2d 1148 (9th Cir. 1973); Criglow v. State, 36 S.W.2d 400 (Ark. 1931). Another court declared that parties should not impeach witnesses by calling other witnesses, and thereby usurp the jury’s task of determining witness credibility. See People v. Johnson, 112 Cal.Rptr. 834 (Cal.App. 1974). Providing somewhat more enlightenment, the Georgia Supreme Court recently concluded:
Generally, expert testimony as to the credibility of a witness is admissible if the subject matter involves organic or mental disorders, such as insanity, hallucinations, nymphomania, retrograde amnesia, and testimony concerning physical maladies which tend to impair mental or physical faculties. If, however, the characteristic attacked does not involve some organic or mental disorder or some impairment of the mental or physical faculties by injury, disease or otherwise, expert testimony is usually excluded.
¶10Jones v. State, 208 S.E.2d 850, 853 (Ga. 1974); see also 20 ALR3d 684.
¶11The cases just cited reject the use of expert testimony to wage a general attack on the validity of direct eyewitness testimony. As to such a general attack, the case authority seems to show a policy decision to avoid a “battle of the experts” by carving out an exception to usual rules permitting expert testimony. In my view, such a policy decision is rational and acceptable, and should be set forth as the basis for our opinion.
¶125. Finally, I note the above opinion’s concluding statement concerning the expert opinion issue, i.e., that any error “on the instant facts, may have been harmless,” is meaningless at best. (Emphasis added.) I respectfully suggest that, when invoking the harmless error rule, this court should utilize care and restraint. Error is either harmless or it is not. That an error may be harmless should not be offered as an ambiguous apologia for uncertainty in other rationale. Our case law and credibility will not be benefited by such non-committal, makeweight declarations.
¶13*153In view of all the foregoing, I respectfully suggest, with all due deference, that the above opinion fails to articulate any real rationale on the expert opinion question. I fear it will mislead more than enlighten.