Hennessey, C.J.
Kostka was found guilty of murder in the first degree, armed robbery, and two counts of assault with a dangerous weapon. His appeal is before us pursuant to G. L. c. 278, §§ 33A-33G.
On appeal, Kostka presents the following as error: (1) the trial judge’s finding that he was competent to stand trial; (2) the trial judge’s allowance of testimony of an out-of-court identification and an in-court identification by a Mrs. Eunice Silverman; (3) the trial judge’s refusal to give instructions on the consequences of a verdict of not guilty by reason of insanity; and (4) the trial judge’s refusal to direct a verdict of not guilty by reason of insanity. We conclude that there was no error in the trial judge’s actions.1
Before considering the issues raised on appeal, we set out the facts adduced at trial. On April 15, 1972, about [518]*51810 p.m., two teenage girls, Diane Kaplan and Nancy Ha-beeb, entered the Salem Street Variety Store in Malden. At that time Murray Cohen was standing behind the counter and a man they later identified as Kostka was standing in front of it. While the two girls were standing at the ice-cream chest, they heard a shot. After they turned around, they heard two more shots and saw Murray Cohen collapse. Kostka then turned toward the girls, pointed his gun at them, and told them to move toward the telephone booth. He then reached behind the counter and grabbed a bag which sounded to the girls as if it contained cash. On his way out of the store Kostka told the girls that if they said anything he would kill them too. Murray Cohen died as a result of the shooting.
Three days later, on April 18, both girls were taken to State police headquarters in Boston where, after viewing hundreds of pictures, they identified pictures of Kostka. Later that day Kostka was arrested by a Boston police officer.
Kostka was also identified by a Mrs. Eunice Silverman, the wife of the owner of the store, who, in response to a composite picture published in a Malden newspaper, called the Malden police to report that she had seen a man fitting the composite description in the store the night before the murder. Mrs. Silverman testified that she was working in the store that evening when, about 10:15 p.m., fifteen minutes before closing time, a man entered the store, stood around the magazine rack for several minutes, and then purchased some potato chips, a pack of cigarettes, and a magazine. Mrs. Silverman testified that the man was in the store for about five or ten minutes and that she observed him closely because she was uneasy about someone entering the store that close to closing time. She also testified that she engaged the man in a brief conversation before he left.
At the time the man entered the store there was another person, who was waiting to take Mrs. Silverman home, present; before that person left, a third person entered [519]*519the store. After Mrs. Silverman saw the composite photograph in a local paper several days later, she called the police, and told them that she was “pretty sure” that a man who had been in the store the night before the murder was the man in the composite drawing. The police came to her home shortly thereafter with about twelve black and white photographs of white males. Two of the twelve pictures were of the defendant — one photograph with glasses on and another without. Of the other ten photographs, there were no duplicates. Mrs. Silverman picked out the two pictures of Kostka. However, it was not until the next day that the police notified her that she had picked out pictures of the suspect.
The evidence presented by Kostka was almost exclusively concerned with his defense of insanity. There was testimony from a number of lay witnesses and from two psychiatrists; additionally, extensive medical records were produced. Without setting out all the evidence produced by the defense, we shall attempt to summarize the evidence on insanity.
Kostka’s mother testified to years of difficulty with her son, starting at age three or four. Kostka had continual problems at school, was disruptive and violent, and was sent to the Middlesex Training School at age nine. He stayed there for about two years, having been classified as a habitual school offender. Although Kostka returned to the Malden public schools at age fourteen, he remained in school for only two months. One year later he was referred to a special program for emotionally disturbed children.
A series of hospital admissions began in 1964, when Kostka was fourteen. Over the next five years Kostka had ten admissions — six at Bridgewater State Hospital (Bridgewater), and two each at Foxborough State Hospital and Metropolitan State Hospital. The admissions lasted from one to seventeen months. Some were the result of prison, court or school references, but most were requested under the provisions of G. L. c. 123. The diagnoses varied [520]*520from “emotionally unstable personality” to “sociopathic personality” to “schizoid personality.” At no time did the diagnoses state that Kostka was overtly psychotic.
After Kostka was arrested for the murder of Murray Cohen, he was initially incarcerated in the Billerica House of Correction. About a month later, because of disruptive conduct there, he was sent to Bridgewater State Hospital. After several weeks of observation, during which Kostka refused to take psychological tests, the staff issued a provisional diagnosis in which they concluded that the defendant had an “[a]nti-social personality disorder, severe, with schizoid and unstable features, possibly decompensating into schizophrenia, paranoid type.” At that time (June, 1972), Kostka was considered by the staff to be incompetent to stand trial. He remained at Bridgewater.
In September, 1972, a staff report reaffirmed the previous diagnosis, but noted that Kostka was “well oriented and in good contact with reality.” In January, 1973, a further review of Kostka’s condition resulted in the same basic diagnosis, but concluded that he was then competent to stand trial. In March, after spending nine months at Bridgewater, pursuant to his own request, he was transferred back to Billerica. Six days later Kostka returned to Bridgewater on the basis of a request by the prison physician. Reevaluation of Kostka’s condition resulted in a reaffirmation of previous diagnoses.
In addition to these medical records and staff evaluations, Kostka presented two experts.2 A Dr. James Christy, the acting medical director of Bridgewater at the time of trial, testified that he had known Kostka for a period of time and that he had examined him on numerous occasions. In June, 1972, Dr. Christy felt that Kostka was “on his way to psychosis.” However, Dr. Christy did not find Kostka to be in a continual state of psychosis.3 While Dr. [521]*521Christy did conclude at trial that the defendant, then twenty-three years old, was “presently mentally ill” and that he probably had been since he was nine or ten years old, Dr. Christy did not have an opinion whether Kostka was criminally responsible on the date of the crime.
The defendant’s other expert, Dr. Robert Mezer, testified that he first examined Kostka in February, 1973. Dr. Mezer expressed his belief that Kostka suffered from chronic paranoid schizophrenia, resulting in the loss of “contact with reality” and “difficulty in adjusting to the requirements [of] life as most people know it.” Dr. Mezer disagreed with the other doctors’ diagnoses of Kostka: he felt Kostka was not simply a sociopath. He concluded that Kostka was not criminally responsible on the date of the crime under the test set forth in Commonwealth v. McHoul, 352 Mass. 544 (1967). He stated that Kostka was suffering from “paranoid schizophrenia,” a “major psychotic illness.” Kostka was thus “not able to conform his conduct to the requirements of the law because of his mental illness.” Dr. Mezer based this conclusion on observation and evaluation of Kostka’s “entire illness” and Kostka’s statements, in February, 1973, about his mental state on the date of the crime.
To rebut this substantial evidence on the issue of insanity, the Commonwealth first called Mrs. Silverman to testify. The Commonwealth argues that her testimony, in addition to identifying Kostka as the man in the store the night before the murder, would permit the inference that Kostka might have been sane because he planned to rob the store when only he and a salesperson would be there.
A registered nurse at Bridgewater also testified in rebuttal. She said that she had known Kostka for about two years. Kostka never caused any difficulties for her, she stated, but he did say that at times he had problems.
Finally, a correction officer at Bridgewater testified that he had cared for Kostka for the three weeks prior to trial. The officer stated that Kostka had actively participated [522]*522with other patients in sports, that he had worked in the print shop, and was neat in appearance. The officer indicated that Kostka did not cause any disturbances during this period — while being confined in a minimum security building — but he did note that Kostka was on medication.
Having set out the facts of the crime and summarized the evidence of insanity, we turn now to the issues raised on appeal.
1. Competence to Stand Trial.
Kostka first argues that the trial judge’s finding that he was competent to stand trial was erroneous. “The test to be applied in determining the competence of the defendant is ‘whether he has sufficient present ability to consult with his lawyer with a reasonable degree of rational understanding and whether he has a rational as well as factual understanding of the proceedings against him.’ ” Commonwealth v. Vailes, 360 Mass. 522, 524 (1971), quoting from Dusky v. United States, 362 U.S. 402 (1960). When there is doubt as to whether the defendant satisfies this test, the judge must, on his own initiative, conduct a full hearing on the issue (Pate v. Robinson, 383 U.S. 375, 385 [1966]; Commonwealth v. Vailes, supra at 524) and “[a] finding of incompetency shall require a preponderance of the evidence.” G. L. c. 123, § 15 (d), as amended through St. 1973, c. 569, § 7. On the evidence adduced here, we conclude that the trial judge was clearly warranted in finding that Kostka was competent to stand trial.
Although there are indications that, at various points prior to trial, Kostka was considered by those treating him to be incompetent to stand trial, the test set out in Dusky is concerned with present abilities. See Pate v. Robinson, supra at 387. Consequently, the question is whether Kostka was competent to stand trial at the actual time of trial in October, 1973. Support for the trial judge’s conclusion may be found in the testimony of Dr. Christy, the acting director of Bridgewater State Hospital. Although Dr. Christy recognized that Kostka had an “anti-social personality” with “early signs of schizophrenia,” he was of the opinion that Kostka was competent to stand trial. Dr. Christy [523]*523testified that Kostka understood both the charges against him and the nature of the proceedings; that he was able to confer with his attorney “with a reasonable degree of rational understanding”; and that he was “very capable” of cooperating with his attorney. These conclusions draw strong support from the fact that Dr. Christy had known Kostka over a period of time and was quite familiar with his medical history.
Dr. Mezer reached the opposite conclusion. However, unlike Dr. Christy, Dr. Mezer had not had an ongoing relationship with Kostka. Rather, he based his conclusions on two brief examinations of Kostka — a total of two and one-half hours — one of which was eight months before trial. Additionally, Dr. Mezer stated that only five or ten minutes of his initial examination was consideration of the question of Kostka’s competence to stand trial.
We conclude that, on the basis of the evidence, there was ample support for the trial judge’s finding that Kostka was competent to stand trial. Accordingly, Kostka was not denied any due process rights in this regard. See Commonwealth v. Vailes, supra at 524, and cases cited.
2. Identification by Mrs. Silverman.
Kostka’s second contention on appeal is that the trial judge erred by not suppressing testimony of the out-of-court identification made by Mrs. Silverman and by allowing Mrs. Silverman to make an in-court identification.
As we have previously noted, Mrs. Silverman called the Malden police after she saw a composite drawing of the suspected murderer in the local newspaper about four days after the crime. The next day a Captain Cornelius Buckley came to Mrs. Silverman’s home with about a dozen photographs of white males between the ages of twenty and twenty-eight, some with glasses and others without glasses. At the voir dire and at trial Mrs. Silverman testified that the photographs were randomly placed on her kitchen table and that she selected two photographs of Kostka — one with glasses and one without. In arguing that the procedure employed by the Malden police was “impermis-sibly suggestive,” see Simmons v. United States, 390 U.S. [524]*524377, 384 (1968), Kostka places substantial reliance on the fact that, of the dozen or so photographs shown to Mrs. Silverman, the only duplicates were of him.
We note that such a practice is not impermissibly suggestive per se. See United States v. Cooper, 472 F.2d 64, 65-66 (5th Cir. 1973). Cf. Commonwealth v. Mobley, 369 Mass. 892, 896 (1976). Nor was the fact that only two of the photographs were of men wearing glasses enough to make the procedure constitutionally defective under Simmons, particularly in light of the fact that Mrs. Silverman picked out a picture of Kostka without glasses.
Furthermore, the out-of-court identification of photographs less than a week after the crime was close to the time Mrs. Silverman had seen Kostka in the store (the night before the crime). Before the composite drawing appeared in the local newspaper, she had spoken to the police (on the night of the crime) and given them an accurate description of Kostka.
Because of our conclusion that the trial judge was warranted in ruling, as he did, that the pre-trial identification process was valid, we need not determine whether the “in-court identification was, by clear and convincing evidence, based on observations of the [defendant] independent from the challenged pre-trial procedures.” Commonwealth v. Mobley, supra at 897 (footnote omitted). We do note that Mrs. Silverman testified on voir dire that she remembered the defendant’s face “as clear as a bell” and she later stated in open court that there was “[n]o question in [her] mind” that the defendant was the person who had been in the store the night before the murder. On the entire evidence, it is very clear that this was not a case in which there was “a very substantial likelihood of irreparable mis-identification.” Simmons v. United States, supra at 384; Commonwealth v. Mobley, supra at 895.
3. Instructions on the Consequences of a Verdict of Not Guilty by Reason of Insanity.
Kostka’s third assignment of error is the trial judge’s refusal to give instructions on the consequences of a verdict of not guilty by reason of insanity. Kostka bases this as[525]*525signment of error on our decision in Commonwealth v. Mutina, 366 Mass. 810, 822 n.12 (1975), in which we held that “in all trials and retrials after this date where the defense of insanity is fairly raised, the defendant, on his timely request, is entitled to an instruction regarding the consequences of a verdict of not guilty by reason of insanity.” Because Kostka’s trial was held in October and November of 1973, over one year before our decision in Mutina, Kostka was not entitled to such an instruction, id. at 811-812, 823 n.12, and there was therefore no error in this regard.
4. The Defense of Insanity.
Kostka’s final contention is that the trial judge erred in denying his motion for a directed verdict of not guilty by reason of insanity, because the Commonwealth failed, as matter of law, to prove him sane beyond a reasonable doubt. Kostka presents a two-step legal analysis in reaching this conclusion. He argues first that, when the issue of insanity is properly before the trier of fact, the Supreme Court’s decision in In re Winship, 397 U.S. 358 (1970), makes the rule that the prosecution must prove sanity beyond a reasonable doubt one of constitutional dimension. His argument then centers on a footnote in Commonwealth v. Mutina, supra, 366 Mass. at 814 n.2. From this he argues that the Commonwealth may not constitutionally satisfy that burden by reliance — in whole or in part4 — on the so called “presumption of sanity,”5 in a case where there [526]*526has been uncontradicted expert testimony that the defendant was insane at the time the crimes were committed. Kostka concludes that, because the Commonwealth could not rely on the presumption of sanity to meet its burden on the issue of sanity and because the other evidence of sanity was so tenuous, a directed verdict was appropriate.6
While we agree that under Massachusetts law the Commonwealth must, when the defense of insanity has been raised, prove a defendant sane beyond a reasonable doubt, we do not agree that Winship, Mutina, or the recent Supreme Court cases referred to in Mutina compel the conclusion that the Commonwealth may not rely on the “presumption of sanity” to meet its burden even in a case where there is uncontradicted expert testimony that the defendant was insane at the time he committed the crime in question.
As part of our consideration of the impact of Winship and other recent Supreme Court decisions on the presumption of sanity as it is employed in Massachusetts, it is essential to examine the presumption of sanity as it has developed both generally and in Massachusetts, and we turn first to that examination.
(a) The General Purpose and Nature of the “Presumption of Sanity.”
In Davis v. United States, 160 U.S. 469, 486 (1895), the Court stated: “[T]he law presumes that every one charged with crime is sane, and thus supplies in the first instance the required proof of capacity to commit crime.” That the prosecution may rely on the presumption in the absence [527]*527of any evidence tending to show insanity is the rule in all jurisdictions. W.R. LaFave & A.W. Scott, Jr., Criminal Law § 40, at 312 (1972). H. Weihofen, Mental Disorder as a Criminal Defense 214-215 & n.l (1954), and cases cited. See Annot., 17 A.L.R.3d 146, 167 (1968). Although all jurisdictions consider insanity to be a defense and apply the “presumption of sanity” in a manner that makes it conclusive on the issue of sanity until some evidence tending to show insanity is adduced,7 at that point the unanimity among jurisdictions ceases to exist.
Twenty-eight jurisdictions, including the Federal government and Massachusetts, provide that, after evidence of insanity has been introduced into the case, the burden devolves on the prosecution to prove the defendant’s sanity beyond a reasonable doubt.8 Twenty-three jurisdictions, including the District of Columbia, consider insanity to be an affirmative defense, and require that the defendant [528]*528prove insanity by a preponderance of the evidence.9 One jurisdiction, Wisconsin, employs both of these rules, depending on which definition of insanity the defendant relies on.10
There is further differentiation among those jurisdictions, like Massachusetts, in which the prosecution bears the ultimate burden on the issue of insanity. In some jurisdictions, including a majority of the Federal circuits, after a certain quantum of evidence tending to show insanity has been introduced,11 the presumption loses all effect.12 However, in at least seven other jurisdictions, of which Massachusetts is one, the “presumption of sanity” does [529]*529not disappear from the case. Rather, the “presumption” is considered to have at least some evidential value.13
In those jurisdictions which place the burden of proving insanity by a preponderance of the evidence on the defendant, it is generally thought to be appropriate to allow the jury to consider the presumption.14
Because of these differences among the jurisdictions, it is difficult to make precise generalizations about the purpose and nature of the presumption on the basis of case law and statutes. Nor are the commentators in accord about the presumption. Compare W.R. LaFave & A.W. Scott, Jr., Criminal Law § 40, at 312 (1972), with A. Gold-stein, The Insanity Defense 120-121 (1967), and H. Weiho-fen, Mental Disorder as a Criminal Defense 214-219 (1954). Indeed, one leading commentator has concluded that the “use of the term presumption is only confusing.” McCormick, Evidence § 346, at 830 (1972).
Although no precise rules governing the presumption in all jurisdictions can be stated with complete accuracy, two general conclusions can be drawn. First, the presumption, as it has traditionally been employed, may, in any given jurisdiction, have procedural or evidential characteristics, or both. Second, the historic and continued variation among jurisdictions suggests that the purpose and nature of the presumption have traditionally been considered to be matters to be defined by courts and Legislatures as [530]*530part of a jurisdiction’s criminal law, rather than by the Constitution.
Nevertheless, there are constitutional limitations on a State’s ability to define its criminal law and procedure. See Mullaney v. Wilbur, 421 U.S. 684 (1975); cf. In re Winship, 397 U.S. 358 (1970). However, the imposition of such limitations — through the due process clause of the Fourteenth Amendment — is rare: “state courts are the ultimate expositors of state law... except in extreme circumstances.” Mullaney v. Wilbur, supra at 691 & n.ll, citing Winters v. New York, 333 U.S. 507 (1948), and Mur-dock v. Memphis, 87 U.S. (20 Wall.) 590 (1875). The specific question we must address is whether the presumption of sanity, as employed in Massachusetts, violates due process. In order to make that inquiry we must first set out the specific purpose of the presumption as developed in the Commonwealth.
(b) The Role of the “Presumption of Sanity” in Massachusetts.
In Massachusetts, the “presumption of sanity” operates procedurally while the facts underlying it operate substantively. As in all jurisdictions, the presumption relieves the prosecution from adducing evidence of sanity in those cases in which the question is not raised. In cases where the question of insanity is raised, as in the instant case, the facts underlying the presumption and the inference that may be drawn from those facts provide a basis for the jury to determine that the defendant was sane beyond a reasonable doubt at the time the crime was committed. In this sense, the “presumption of sanity” is merely an expression we have used to describe both “the fact that a great majority of men are sane,” Commonwealth v. Clark, 292 Mass. 409, 415 (1935), and “the probability that any particular man is sane,” id., from which the jury may conclude that the defendant is sane. See Commonwealth v. Mutina, 366 Mass. 810, 814 n.2 (1975); Commonwealth v. Cox, 327 Mass. 609, 613 (1951). Furthermore, our past decisions make it clear that it is not the presumption itself that is weighed as evidence; rather, the jury weigh the facts un[531]*531derlying the presumption and the inferences that may follow from those facts (Commonwealth v. Mutina, supra; Commonwealth v. Cox, supra; Commonwealth v. Clark, supra; see H. Weihofen, Mental Disorder as a Criminal Defense 217 [1954]), facts which are considered to be part of the jury’s “common experience that most people ... are sane.” United States v. Dube, 520 F.2d 250, 255 (1st Cir. 1975) (Campbell, J., concurring).
Because the presumption serves two purposes in the Commonwealth, we do not think that it can be accurately classified as a presumption. Similarly, although an inference may be drawn from the facts underlying the presumption, we do not think that the presumption and the facts underlying it may be properly termed an inference. We recognize that the “presumption of sanity” shares, but is not limited to, the characteristics of both presumptions and inferences. We are reluctant to attempt to classify the “presumption of sanity” more precisely, and we do not believe that such classification would be helpful to our present inquiry.
Having set out the role of the presumption and the facts underlying it, we turn now to the question whether use of the presumption in Massachusetts constitutes a violation of due process in light of In re Winship, 397 U.S. 358 (1970), and other relevant cases.
(c) The Effect of Winship and Other Supreme Court Cases.
The critical language in Winship is the court’s explicit holding that “the Due Process Clause protects the accused against conviction except upon proof beyond a reasonable doubt of every fact necessary to constitute the crime with which he is charged.” 397 U.S. at 364. It has long been the law of this Commonwealth that, when the defendant’s sanity is in issue, the prosecution bears the burden of proving sanity beyond a reasonable doubt. In Commonwealth v. Johnson, 188 Mass. 382, 388 (1905), it was said that the “statement... that the burden of proof was upon the Commonwealth to satisfy [the jury] beyond a reasonable doubt that [the defendant] was... sane... [532]*532[was] the law... fully and correctly stated.” See also Davis v. United States, 160 U.S. 469, 483 (1895). That the burden is on the Commonwealth has often been reiterated. See, e.g., Commonwealth v. Mutina, 366 Mass. 810, 814 n.2 (1975); Commonwealth v. Smith, 357 Mass. 168, 177 (1970); Commonwealth v. Clark, 292 Mass. 409, 415 (1935). Even if, under Winship, sanity is a “fact” of the crime in such cases, the effect of Winship is not to alter the prosecution’s burden, but to make it one of constitutional proportions.
While we believe that, under Winship, sanity becomes a “fact” of the crime charged after evidence of insanity has been adduced, we do not believe that sanity is an “element” of any given crime.15 Insanity is a defense to the crime charged. Although once the issue has been raised it is necessary for the prosecution to prove sanity beyond a reasonable doubt, it is not necessary for the prosecution to prove sanity — nor would instructions on the presumption of sanity be appropriate — before the issue is raised. See Davis v. United States, 160 U.S. at 488. This distinction — between the “elements” of the offense charged and “facts” which, after Winship, the prosecution must prove beyond a reasonable doubt — is important in determining the due process standard to be applied to the presumption of sanity.16 If sanity were an “element” of the crime [533]*533charged, then recent Supreme Court cases on the use of presumptions and inferences to establish an element of the offense would be apposite to our inquiry. Because sanity is not an element of the crime charged, we do not think that cases like Barnes v. United States, 412 U.S. 837 (1973), Turner v. United States, 396 U.S. 398 (1970), and Leary v. United States, 395 U.S. 6 (1969) ,17 which concerned the use of statutory and common law inferences to establish an element of the crime charged, set forth the appropriate test. Rather, we think that the appropriate standard is set out in Leland v. Oregon, 343 U.S. 790 (1952).
In Leland, the Supreme Court considered the constitutionality of the then existing Oregon practice of requiring the defendant to prove his insanity beyond a reasonable doubt. The Court concluded that the practice was constitutional. In making that determination, the Court set forth the applicable standard: whether the “policy [in question] violates generally accepted concepts of basic standards of justice.” Id. at 799. See also United States v. Caldwell, 543 F.2d 1333 (D.C. Cir. 1974), cert. denied, 423 U.S. 1087 (1976).
Although this standard is of necessity imprecise, Leland provides other guidelines that are helpful to our inquiry. The fact that a challenged practice “is followed by a large number of states ... is plainly worth considering in determining whether the practice ‘offends some principle of justice so rooted in the traditions and conscience of our people as to be ranked as fundamental.’ ” Leland v. Oregon, supra at 798, quoting from Snyder v. Massachusetts, 291 U.S. 97,105 (1934). Cf. Mullaney v. Wilbur, 421 U.S. 684, 701 (1975). However, the fact that a large number of jurisdictions follow a certain rule “is not conclusive” in such an inquiry. Leland v. Oregon, supra at 798.
[534]*534It is true that only a minority of the jurisdictions requiring the prosecution to prove the defendant’s sanity beyond a reasonable doubt — once the issue has been raised by sufficient evidence — allow the jury to consider the presumption or the facts underlying the presumption. But the practice draws support from the Supreme Court’s decision in Davis v. United States, 160 U.S. 469 (1895), a decision which is still frequently cited and which remains vital. See, e.g., Mullaney v. Wilbur, supra at 702-703 n.31; United States v. Caldwell, supra 543 F.2d at 1371 (denial of rehearing) ; United States v. Dube, 520 F.2d 250, 254 (1st Cir. 1975) (Campbell, J., concurring); State v. Lass, 228 N.W.2d 758, 768 (Iowa 1975). In Davis, the Court explicitly stated that the presumption of sanity possessed evidential value which the jury could consider; thus the Court referred to “the whole evidence, including that supplied by the presumption of sanity” (emphasis supplied). 160 U.S. at 488.
The view of the presumption adopted in Massachusetts has also been adopted by the Court of Appeals for the District of Columbia. In Keys v. United States, 346 F.2d 824, 826 (D.C. Cir.), cert. denied, 382 U.S. 869 (1965), then Circuit Judge Burger wrote: “The presumption of sanity, whatever may be its evidentiary value and weight, does not vanish from the case, as [defendant] would have it. That presumption is grounded on the premise that the generality of mankind is made up of persons within the range of ‘normal,’ rational beings and can be said to be accountable or responsible for their conduct; this premise is rooted in centuries of experience, has not been undermined by contemporary medical knowledge, and justifies the continuance of the presumption after introduction of evidence of insanity.”
In People v. Silver, 33 N.Y.2d 475, 482-483 (1974), the New York Court of Appeals quoted with approval the case of Brotherton v. People, 75 N.Y. 159, 163 (1878), for the proposition that, when a jury question as to insanity is presented, “ ‘the presumption of sanity, and the evidence, [535]*535are all to be considered.’ ” Several other jurisdictions have also reached this result in recent cases, some of which involved due process attacks on the use of the presumption as evidence for the jury’s consideration. See State v. Daniels, 106 Ariz. 497, 501-502 (1970); State v. Lass, 228 N.W.2d 758, 768 (Iowa 1975); People v. Gray, 57 Mich. App. 289, 298 (1975); State v. Wilson, 85 N.M. 552, 555 (1973). Cf. United States v. Dube, 520 F.2d 250, 255 (1st Cir. 1975) (Campbell, J., concurring).
Although it is true that allowing the jury to consider the presumption is a minority position among the jurisdictions that require proof of sanity beyond a reasonable doubt, it is also true that, in those jurisdictions in which the defendant bears the burden of persuasion on the issue of insanity, the presumption is often submitted to the jury for their consideration. This view was articulated by the Maryland Court of Appeals in Bradford v. State, 234 Md. 505, 513 (1964), where the court stated that, in jurisdictions in which the burden of persuasion is on the defendant, “the presumption of sanity is an inference of fact from which the trier of facts can draw conclusions of fact.” Accord, State v. King, 526 S.W.2d 58, 59 (Mo. App. 1975). See H. Weihofen, Mental Disorder as a Criminal Defense 216 (1954); Note, Burden of Proof of Insanity in Criminal Cases, 15 Md. L. Rev. 157, 160-161, 163-164 (1955). Thus, it may well be that a majority of jurisdictions in fact submit the presumption to the jury, with the presumption (or the facts underlying it) having some evidential value. We think that, even if this were not the case, our practice would still not run afoul of the Leland standards, for there are fundamentally sound reasons for our practice.
First, there are situations in which a jury may justifiably conclude that a defendant is not insane, despite uncontradicted testimony from the defendant’s experts that he is insane. In any given case, the jury may have cogent reasons for disbelieving or disregarding such testimony. The defendant’s witnesses may have examined him for such a short period of time, at a time so far removed from [536]*536the crime, or in such other circumstances that the jury may properly conclude that the testimony is so lacking in credibility or so insufficient in weight that it does not raise a reasonable doubt. That jurors are the ultimate judges of expert testimony and that such testimony is not conclusive are concepts we have recently reaffirmed in cases involving the defense of insanity. Commonwealth v. Costa, 360 Mass. 177 (1971). Commonwealth v. Smith, 357 Mass. 168 (1970). Commonwealth v. Ricard, 355 Mass. 509 (1969). As we said in Commonwealth v. Smith: “The jury are... the sole judges of the credibility and weight of all of the evidence on the issue of insanity____The jury are not compelled to believe any such testimony or opinions, and the court cannot order them to do so by directing them to return verdicts of not guilty by reason of insanity----The law should not, and does not, give the opinions of experts on either side of the issue the benefit of conclusiveness, even if there are no contrary opinions introduced at the trial.” 357 Mass. at 178.
Second, we believe that the facts underlying the presumption are within the jury’s common sense and knowledge and that it would be inappropriate and artificial to forbid jurors to rely, at least in part, on their common experience. See Commonwealth v. Hosman, 257 Mass. 379, 386 (1926); United States v. Dube, 520 F.2d 250, 254-255 (1st Cir. 1975) (Campbell, J., concurring). Cf. Keys v. United States, 346 F.2d 824, 826 (D.C. Cir.), cert. denied, 382 U.S. 869 (1965). “[I]n deciding the issue of insanity in a criminal case, the jury may infer that the defendant is sane from their common knowledge of the fact that a great majority of men are sane, and of the probability that any particular man is sane.” Commonwealth v. Smith, supra at 179. See Commonwealth v. Clark, 292 Mass. 409, 415 (1935).
Finally, it is, and has been for over seventy years, incumbent on the Commonwealth to prove sanity beyond a reasonable doubt. This is not an insignificant burden, and is a safeguard against erroneous convictions. Thus, unlike almost half of the other jurisdictions, we have required [537]*537this standard of proof on the fact of sanity after the question has been raised. Even with the jury being allowed to consider the facts underlying the presumption, this standard must be met, or acquittal by reason of insanity is appropriate. We do not attempt to denigrate the proof necessary to meet this standard by noting that at least twenty-three jurisdictions place the burden of persuasion on the issue on the defendant, but we do think that the existence of that practice is relevant to our conclusion that our practice does not violate “generally accepted concepts of basic standards of justice.” Leland v. Oregon, 343 U.S. 790, 799 (1952) ,18
Because of our conclusion that the presumption of sanity, as used in Massachusetts, does not violate due process, we find no error in the trial judge’s refusal to direct a verdict of not guilty by reason of insanity.
5. Disposition Under G. L. c. 278, § 33E.
Although Kostka has not argued that we should set the verdict aside under G. L. c. 278, § 33E, because it was against the weight of the evidence, “we are required ‘to consider the whole case broadly to determine whether there was any miscarriage of justice.’ ” Commonwealth v. Mutina, 366 Mass. 810, 812 (1975), quoting from Commonwealth v. Ransom, 358 Mass. 580, 583 (1970), and Commonwealth v. Baker, 346 Mass. 107, 109 (1963). After examination of the transcript and the record pursuant to our duties under § 33E, a majority of the court conclude that the verdict should not be set aside.
We believe that the instant case can be distinguished [538]*538readily from the cases in which we have determined that the defendant’s evidence of insanity was so compelling that reversal under § 33E was appropriate. In Commonwealth v. Mutina, supra, the defendant approached the murder victim as she returned home from a date one evening, stared at her and her companion for about a minute, and then fired two shots, one of which killed her. In Mu-tina, like the case of Commonwealth v. Cox, 327 Mass. 609 (1951), there was neither an intelligent plan nor a rational motive for the murder. In Cox, the defendant attempted to kill his wife by bludgeoning her with a hammer while she was playing the piano; not being immediately successful, he then lacerated her body with an ice pick and attempted to strangle her with a wire.
The facts of the instant case, on the other hand, warrant an inference by the jury that Kostka engaged in a carefully considered, intelligent plan to commit the crimes with which he is charged. It could be found that his motive was profit. As we have noted, the testimony of Mrs. Silverman permitted the conclusion that Kostka planned to rob the store at a time when only he and a salesperson would be present. Further, his threats to the girls in the store were clearly for the purpose of assuring his escape. The jury could properly consider these examples of restraint and caution as relevant to the dual tests (Commonwealth v. McHoul, 352 Mass. 544, 546 [1967]) of sanity, viz.: capacity to appreciate the wrongfulness of his conduct, and to conform his conduct to the requirements of the law. That the circumstances of the crime may be relied on to help establish sanity at the time the crime was committed is a principle that was firmly established in Commonwealth v. Smith, 357 Mass. 168, 178-180 (1970), and one that is widely accepted. See W.R. LaFave & A.W. Scott, Jr., Criminal Law § 40, at 315 (1972); H. Weihofen, Mental Disorder as a Criminal Defense 312-315 (1954); Annot., 17 A.L.R.3d 146,179-181 (1968 & Supp. 1975), and cases cited.
Furthermore, although there was no expert testimony that Kostka was sane at the time the crimes were com[539]*539mitted, we think it particularly significant that Dr. Christy, who had known Kostka for a period of years and was quite familiar with his medical history, did not have an opinion whether Kostka was insane at the time the crimes were committed. Although Dr. Mezer testified that Kostka was insane at that time, we note that the jury, because of the brevity of the relationship between Kostka and Dr. Mezer, would have been justified in according little weight to Dr. Mezer’s conclusion.
Accordingly, after reviewing the entire evidence under § 33E, we conclude that justice does not require the ordering of a new trial, and does not require us otherwise to disturb the verdict of the jury.
Judgments affirmed.