¶1(concurring). I concur in affirming the judgments
¶2of conviction against the defendant. I write separately to set forth my thoughts on the issue of juror bias raised in this case.
¶3I agree with the judge that Juror Y’s statement that the victim’s injuries would result “when a big black man” beat a small woman raised the specter of racism, warranting closer examination. Indeed, Juror Y’s statement provoked an immediate reaction from the black female juror (Juror A), who accused Juror Y of racism. The confrontation included the two women yelling back and forth and swearing at each other.
¶4In assessing whether the defendant met his burden to prove that Juror Y was actually biased, Smith v. Phillips, 455 U.S. 209, 215 (1982), the judge very conscientiously and sensitively *499explored the issue of racial bias and juror taint, including a careful determination of credibility and context. I agree that his findings are not clearly erroneous. Commonwealth v. Amirault, 399 Mass. 617, 626 (1987). However, there is one conversation between Juror Y and Juror A that I would have explored further to broaden the context of Juror Y’s statement. That is, Juror A claimed that, at some point during the day that Juror Y made her statement about the defendant’s race, Juror Y also asked Juror A about her hairstyle and the level of education she had achieved. Juror A told the judge that the comments were made in a “snide” manner, “suggesting racial bias.”
¶5“Since the 1990’s, a number of studies have deconstructed the complicated ways in which the human mind maintains and manifests racially biased implicit attitudes and stereotypes. Many of these studies have reached the same conclusion — that implicit biases are real, pervasive, and difficult to change .... [Moreover] racial attitudes and stereotypes are both automatic and implicit. That is, that people possess attitudes and stereotypes over which they have little or no ‘conscious, intentional control.’ Levinson, Forgotten Racial Equality: Implicit Bias, Decisionmaking and Misremembering, 57 Duke L.J. 345, 351-354 (2007) (Levinson). This is because, according to “[Research on stereotype formation and maintenance^] . . . stereotypes are instilled at an early age and come from cultural and societal beliefs. . . . [Psychologists have found that stereotypes arise when a person is as young as three years old and are usually learned from parents, peers, and the media. As people grow older, their stereotypes become implicit and remain mostly unchanged even as they develop nonprejudiced explicit views. ‘Stereotypes about ethnic groups appear as a part of the social heritage of society. . . . [And] [n]o person can grow up in a society without having learned the stereotypes assigned to the major ethnic groups.’ Id. at 363, quoting Page, Batson’s Blind-Spot: Unconscious Stereotyping and the Peremptory Challenge, 85 B.U. L. Rev. 155, 203 n.22 (2005). See Symposium Forbidden Conversations: On Race, Privacy, and Community (A Continuing Conversation with John Ely on Racism and Democracy), 114 Yale L. J. 1353, 1391 (2005) (individuals restrict their racist speech).
¶6Courts are aware that unconscious racism could affect the *500outcome of trials. See Commonwealth v. Laguer, 410 Mass. 89, 99 (1991), quoting Smithv. Phillips, supra at 221-222 (O’Connor, J., concurring) (“Determining whether a juror is biased or has prejudged a case is difficult, partly because the juror may have an interest in concealing his own bias and partly because the juror may be unaware of it”). See also Georgia v. McCollum, 505 U.S. 42, 68 (1992) (O’Connor, J., dissenting) (“It is by now clear that conscious and unconscious racism can affect the way white jurors perceive minority defendants and the facts presented at their trial, perhaps determining the verdict of guilt or innocence”).
¶7The judge here expressed his understanding of unconscious bias by relying, in part, on the defendant’s “expert social psychologist on matters of racial bias,” Samuel R. Sommers, and stating that he was assessing Juror Y’s testimony through the filter of Justice O’Connor’s concurring opinion in Smithv. Phillips, supra at 221-222 (O’Connor, J., concurring), concerning unconscious bias.
¶8As the judge also recognized, courts use mechanisms that studies suggest can counteract implicit racially based attitudes and stereotypes. Here, during the voir dire, the judge asked each juror about their attitudes about race.
¶9Given the societal norm that one does not overtly express racially biased attitudes, see Sommers, 7 Psychol., Pub. Pol’y & L., supra at 208, as well as the mechanisms to which the jurors were exposed before their deliberations, Juror Y’s “big *502black man” statement is all the more remarkable. I recognize that her statement could have been parroting the statements of defense counsel,
¶10Because of unconscious racism, it is the subtle clues that help give a judge insight into a juror’s true feelings. Indeed, the judge here explored in detail such a subtlety: whether Juror Y said “this” big black man rather than “a” or “the” big black man. He found that she was referring directly to the defendant and concluded that she did not harbor prejudice against blacks as a class but was speaking descriptively of the defendant. A similar analysis of the hair and education questions would have added another dimension to the judge’s analysis. Both questions, but particularly the question about Juror A’s level of education, implicate racial stereotyping. See Lawrence, supra. I would want to know whether Juror Y asked other jurors about their education or asked just Juror A.
¶11I agree with the court that the judge’s task here was tremendously difficult, ante at 494, and do not suggest that the judge would have reached a different conclusion concerning whether Juror Y was actually biased. I do think that more inquiry concerning whether any other jurors were asked questions about their level of education and hairstyle would have given context and insight into whether the questions put to Juror A were simply small talk or indicative of implicit bias.
¶12To support her statement, Justice O’Connor cited Developments in the Law — Race and the Criminal Process, 101 Harv. L. Rev. 1472, 1559-1560 (1988); Colbert, Challenging the Challenge: Thirteenth Amendment as a Prohibition against the Racial Use of Peremptory Challenges, 76 Cornell L. Rev. 1, 100-112 (1990). A more recent study concluded that judges and jurors unknowingly “misremember” facts in a case in racially biased ways. Levinson, Forgotten Racial Equality: Implicit Bias, Decisionmaking, and Misremembering, 57 Duke L.J. 345, 373-374 (2007).
¶13Although, as the judge pointed out, judges are free to reject expert testimony, I note that the role of experts in assisting the court in understanding unconscious racism in all its forms could be critical. Although Samuel Sommers testified that, for obvious reasons, research about juror behavior and attitudes has been conducted with mock juries and trials, he conducted at least one study in which he chose his test subjects from a “jury-eligible community.” See Sommers, On Racial Diversity and Group Decision Making: Identifying Multiple Effects of Racial Composition on Jury Deliberations, 90 J. Personality & Soc. Psychol. 597, 601-602 (2006).
¶14The judge stated that the case involved an allegation that the defendant, who is black, raped and killed a white woman and asked whether this information about race would affect the juror’s ability to be fair and impartial. He also asked whether the juror would believe the testimony of a white person *501over a black person and vice versa, and whether the juror believed that blacks are more likely to commit crimes than whites. According to at least one study, simply asking jurors these types of questions calls the issue of race to their attention, what they call “race salience,” making it more likely that juror bias will be reduced. Sommers, 90 J. Personality & Soc. Psychol., supra at 601, 607. See Sommers, White Juror Bias: An Investigation of Prejudice Against Black Defendants in the American Courtroom, 7 Psychol., Pub. Pol’y & L. 201, 220-222 (2001).
¶15According to one study, “racially diverse juries deliberated longer, discussed more trial evidence, and made fewer factually inaccurate statements in discussing the evidence than did all-White juries. Interestingly, these effects, too, cannot be explained solely in terms of the performance of Black jurors, as White jurors were more thorough and accurate during deliberations on diverse vs. all-White juries. A potential implication of these findings is that one process through which a diverse jury composition exerts its effects is by leading White jurors to process evidence more thoroughly.” Sommers, Race and the Decision Making of Juries, Legal & Criminological Psychol. 171, 181 (2007), citing Sommers, 90 J. Personality & Soc. Psychol., supra at 612.
¶16Defense counsel argued in his opening, during examination of witnesses, and in closing that jurors needed to put aside hasty conclusions and consider the possibility that the defendant and the victim had a consensual relationship and that she was killed by a third party. In his articles about race salience, see note 3, supra, the defense expert Sommers found that when the issue of race is brought to the attention of mock jurors, white jurors were less likely to demonstrate bias in their decision making. Sommers, 7 Psychol., Pub. Pol’y & L., supra at 220, 225.
¶17Here, as the judge found, several jurors, including juror A and the foreperson, more than once reminded jurors that race should play no role in deliberations that should be focused on the evidence. See note 4, supra, discussing that racially diverse mock jurors were more thorough in their deliberations than all white mock juries.
¶18In fact, Juror Y testified that she was using the phrase because defense counsel did, and another juror testified that race was mentioned in the context of argument by defense counsel.
¶19Juror A’s reaction is not unusual. Studies show that blacks and whites perceive incidents of discrimination differently. Whites expect discrimination to be explicit, whereas blacks are more aware of implicit discrimination. See Robinson, Perceptual Segregation, 108 Colum. L. Rev. 1093, 1127-1128 (2008) (Robinson), quoting Sommers, Lay Theories About White Racists: What Constitutes Racism (and What Doesn’t), 9 Group Processes & Intergroup Rel. 117, 132 (2006) (“white and nonwhite respondents [were asked] to review a list of behaviors and report whether the behavior was typical of white racism. [Researchers] found that ‘non-Whites are more likely to consider subtle forms of bias to be indicative of racism than are Whites’ ”); Chew, Judicial Decisions, Pitt Law Magazine 8, 9 (2010) (race of judge affected likelihood that plaintiff would prevail in employment discrimination claim and that most successful claims involved supervisors and coworkers “using racial slurs or by ‘ganging up’ on the plaintiff”).
¶20According to Chester Pierce, a graduate of Harvard College and Harvard Medical School, and Emeritus Professor of Education and Psychiatry at the medical school, Graduate School of Education, and School of Public Health at Harvard University, a psychiatrist at Massachusetts General Hospital, and author of over 200 articles, who has served as president, chairperson, advisor, and consultant to numerous organizations, the interactions between white and black individuals in the larger society is marked by what he calls “offensive mechanisms” which are made automatic by the culture and “stem[] from the need of whites to reaffirm and reassert feelings and ideas of racial superiority.” *503C. Pierce, Offensive Mechanisms, The Black Seventies 265, 277 (F. B. Barbour, ed. 1970). He relates the following experience as an illustration:
“I notice in a class I teach that after each session a white, not a black, will come up to me and tell me how the class should be structured or how the chairs should be placed or how there should be extra meetings outside the classroom, etc. [It is possible that I am hypersensitive.] What I cannot explain ... is that it is not what the student says in this dialogue, it is how he approaches me, how he talks to me, how he seems to regard me. ... I was told . . . that although I am a full professor on two faculties at a prestigious university, to him ... I had to be instructed and directed as to how to render him more pleasure!”
¶22Two studies have demonstrated that white test subjects minimize charges of racial discrimination. In sum, in each test, one concerning employment and one concerning grading a college student’s essay, whites were informed that the person who could have evaluated a mock black subject was prejudiced. Nevertheless, they were more likely to call the black subject who asserted discrimination a “complainer” or “troublemaker.” See Robinson, supra at 1148-1151.