"An accused has a constitutional right to a trial by an impartial jury. . An impartial jury is one in which no member has been improperly influenced citations and every member is '"capable and willing to decide the case solely on the evidence before it"' ." (In re Hamilton (1999) 20 Cal.4th 273, 293-294 (Hamilton).) "A sitting juror's involuntary exposure to events outside the trial evidence, even if not 'misconduct' in the pejorative sense, may require similar examination for probable prejudice." (Id. at pp. 294-295.) When the alleged misconduct involves an unauthorized communication with a juror, the presumption of prejudice does not arise unless there is a showing that the content of the communication was about the guilt or innocence of the defendant. (Id. at p. 305.) "Misconduct by a juror, or a nonjuror's tampering contact or communication with a sitting juror, usually raises a rebuttable 'presumption' of prejudice. ." (Hamilton, supra, 20 Cal.4th at p. 295.) The test for whether an individual verdict must be overturned for jury misconduct or irregularity is an objective standard: the substantial likelihood test. (Id. at p. 296.) "Any presumption of prejudice is rebutted, and the verdict will not be disturbed, if the entire record in the particular case, including the nature of the misconduct or other event, and the surrounding circumstances, indicates there is no reasonable probability of prejudice, i.e., no substantial likelihood that one or more jurors were actually biased against the defendant. ." (Ibid.) "A sitting juror commits misconduct by violating her oath, or by failing to follow the instructions and admonitions given by the trial court. A lay juror cannot be expected to conform to standards of behavior of which she has not been informed, or to make unguided personal judgments about what the court needs to know. Her failure to do so cannot place at risk a presumptively valid verdict." (Hamilton, supra, 20 Cal.4th at p. 305.) A jury verdict may be vacated on the basis of jury misconduct that materially affected the substantial rights of a party. (Code Civ. Proc., 657, subd. (2).) "Experiments by the jury or a juror and unauthorized conversations about the case, outside the ambit of deliberations, may constitute misconduct sufficient to warrant a new trial." (Bell v. State of California (1998) 63 Cal.App.4th 919, 930.) "When a defendant moves for a new trial based on juror misconduct, the trial court undertakes a three-step inquiry." (People v. Sanchez (1998) 62 Cal.App.4th 460 475.) First, the court determines whether the declarations and other evidence supporting the motion are admissible. (Ibid.) Second, the court determines from the admissible evidence whether the facts establish juror misconduct. (Ibid.) Third, if the court finds misconduct occurred, it must determine whether the conduct was prejudicial. (Ibid.) "In making the determination as to the admissibility of the evidence presented, including declarations of jurors, '. . . the trial court must take great care not to overstep the boundaries established by Evidence Code section 1150.'" (Sanchez, supra, 62 Cal.App.4th at p. 475.) Evidence Code section 1150, subdivision (a) states: "Upon an inquiry as to the validity of a verdict, any otherwise admissible evidence may be received as to statements made, or conduct, conditions, or events occurring, either within or without the jury room, of such a character as is likely to have influenced the verdict improperly. No evidence is admissible to show the effect of such statement, conduct, condition, or event upon a juror either in influencing him to assent to or dissent from the verdict or concerning the mental processes by which it was determined." When juror misconduct has occurred, prejudice is presumed and the prosecution bears the burden of rebutting the presumption. (People v. Marshall (1990) 50 Cal.3d 907, 949-951.) The conviction must be reversed if the misconduct impaired jury impartiality, lightened the prosecution's burden of proof, or negated a defense. (People v. Von Villas (1992) 11 Cal.App.4th 175, 256.) "We accept the trial court's credibility determinations and findings on questions of historical fact if supported by substantial evidence. Whether prejudice arose from juror misconduct, however, is a mixed question of law and fact subject to an appellate court's independent determination." (People v. Nesler (1997) 16 Cal.4th 561, 582.) A criminal defendant has the right to a trial by an impartial jury in which each juror is capable and willing to decide the case solely on the evidence presented at trial and free of improper influence. (In re Hamilton (1999) 20 Cal.4th 273, 293-294.) To protect this right, the trial court may grant a new trial when the jury "has received any evidence out of court," engaged in "misconduct by which a fair and due consideration of the case has been prevented," or reached its verdict "by any means other than a fair expression of opinion." ( 1181, subds. (2), (3) & (4).) However, there are limitations on the type of evidence that may be used to prove a claim of juror misconduct. Under Evidence Code section 1150, "any otherwise admissible evidence may be received as to statements made, or conduct, conditions, or events occurring, either within or without the jury room, of such a character as is likely to have influenced the verdict improperly." (Evid. Code, 1150, subd. (a).) But "no evidence is admissible to show the effect of such statement, conduct, condition, or event upon a juror either in influencing him to assent to or dissent from the verdict or concerning the mental processes by which it was determined." (Ibid.) Evidence Code section 1150 thus "prevents one juror from upsetting a verdict of the whole jury by impugning his own or his fellow jurors' mental processes or reasons for assent or dissent." (People v. Hutchinson (1969) 71 Cal.2d 342, 350.) In fact, no evidence can be used to substantiate a claim of juror misconduct if it reflects a juror's "reasons for his or her vote" or "their decision making processes." (People v. Lewis (2001) 26 Cal.4th 334, 389.) Moreover, because Evidence Code section 1150 requires that the evidence be "otherwise admissible," "'a jury verdict may not be impeached by hearsay affidavits.' " (People v. Williams (1988) 45 Cal.3d 1268, 1318-1319.) Upon receiving allegations of juror misconduct, the court may choose to "conduct an evidentiary hearing to determine the truth or falsity of those allegations . . ., and to permit the parties to call jurors to testify at such a hearing. This does not mean, however, that a trial court must hold an evidentiary hearing in every instance of alleged jury misconduct. The hearing . . . should be held only when the defense has come forward with evidence demonstrating a strong possibility that prejudicial misconduct has occurred. Even upon such a showing, an evidentiary hearing will generally be unnecessary unless the parties' evidence presents a material conflict that can only be resolved at such a hearing." (People v. Hedgecock (1990) 51 Cal.3d 395, 419.) Moreover, even if juror misconduct has been shown by competent evidence, it is not necessarily cause for a reversal. Some forms of misconduct are inherently nonprejudicial and others may be harmless when viewed in the context in which they occurred. (People v. Bennett (2009) 45 Cal.4th 577, 626-627; People v. Miranda (1987) 44 Cal.3d 57, 117.) "Any presumption of prejudice is rebutted, and the verdict will not be disturbed, if the entire record in the particular case, including the nature of the misconduct or other event, and the surrounding circumstances, indicates there is no reasonable probability of prejudice, i.e., no substantial likelihood that one or more jurors were actually biased against the defendant. " (In re Hamilton, supra, 20 Cal.4th at p. 296.)"A defendant accused of a crime has a constitutional right to a trial by unbiased, impartial jurors. (U.S. Const., 6th and 14th Amends.; Cal. Const., art. I, 16;) A defendant is 'entitled to be tried by 12, not 11, impartial and unprejudiced jurors. "Because a defendant charged with a crime has a right to the unanimous verdict of 12 impartial jurors , it is settled that a conviction cannot stand if even a single juror has been improperly influenced." ' " ( People v. Nesler (1997) 16 Cal.4th 561, 578.) It is misconduct for a juror to "resort to outside sources for amplification of instructions" and "to obtain information from outside sources either as to factual matters or for guidance on the law." ( People v. Karis (1988) 46 Cal.3d 612, 642; see 1137.) Thus, reading of a newspaper containing any matter pertinent to the trial introduces extraneous information to the jury and constitutes misconduct. ( People v. Holloway (1990) 50 Cal.3d 1098, 1108, disapproved on another ground by People v. Stansbury (1995) 9 Cal.4th 824, 830, 889.) It also is misconduct for the jurors to separate during deliberations. ( People v. Dorsey (1995) 34 Cal.App.4th 694, 702, 704 misconduct for juror to leave jury room for 10 minute break while other jurors finalized wording of note to judge.) Juror misconduct raises a presumption of prejudice, and unless the prosecution rebuts that presumption by proof that no prejudice actually resulted, the defendant is entitled to a new trial. ( People v. Pierce (1979) 24 Cal.3d 199, 207.) Although we are deferential to the trial court's findings of fact and credibility, the question of whether juror misconduct was prejudicial is for our independent review. ( In re Carpenter (1995) 9 Cal.4th 634, 658-659, posttrial prejudice is mixed question of law and fact to be determined by reviewing court.) "A defendant accused of a crime has a constitutional right to a trial by unbiased, impartial jurors." (People v. Nesler (1997) 16 Cal.4th 561, 578 (Nesler).) Due process requires that the jury be "'capable and willing to decide the case solely on the evidence before it . . . .'" (Ibid., citing Smith v. Phillips (1982) 455 U.S. 209, 217 71 L.Ed.2d 78, 102 S.Ct. 940.) A juror is not impartial if that juror cannot "'lay aside his impression or opinion and render a verdict based on the evidence presented in court.'" (Nesler, supra, at pp. 580-581, quoting Irvin v. Dowd (1961) 366 U.S. 717, 722-723 6 L.Ed.2d 751, 81 S.Ct. 1639.) It is misconduct for jurors to obtain evidence from sources other than in court, and this constitutes grounds for a new trial if the defendant has been prejudiced thereby. ( 1181, cl. 2; People v. Marshall (1990) 50 Cal.3d 907, 949-951.) Whether this rule applies to jurors' perceptions of a defendant is unclear; however, as a matter of policy, a defendant is not permitted to profit from his own volitional conduct. (People v. Williams (1988) 44 Cal.3d 1127, 1156 new trial denied where the defendant threatened jurors after guilt phase, but before penalty phase, citing People v. Manson (1976) 61 Cal.App.3d 102, 157 testimony about witness's observations of an "X" on the defendant's forehead, and "X's" on the foreheads of the defendant's associates the following day, was properly admitted and could not be prejudicial because "the stigmatic effect of this circumstance, if any, was produced entirely by the voluntary act of appellants"; see also People v. Pride (1992) 3 Cal.4th 195, 253-254 the defendant cannot claim prejudice when he chose to appear at the penalty phase in jail clothes and shackles.) Misconduct by a juror usually raises a rebuttable presumption of prejudice. (People v. Danks (2004) 32 Cal.4th 269, 302, citing In re Hamilton (1999) 20 Cal.4th 273, 295.) However, "'"the introduction of much of what might strictly be labeled 'extraneous . . .' cannot be deemed misconduct. The jury system is an institution that is legally fundamental but also fundamentally human. Jurors bring to their deliberations knowledge and beliefs about general matters of law and fact that find their source in everyday life and experience. That they do so is one of the strengths of the jury system. It is also one of its weaknesses; it has the potential to undermine determinations that should be made exclusively on the evidence introduced by the parties and the instructions given by the court. Such a weakness, however, must be tolerated. 'It is an impossible standard to require . . . the jury to be a laboratory, completely sterilized and freed from any external factors.'"'" (People v. Loker (2008) 44 Cal.4th 691, 747, quoting People v. Danks, supra, at p. 302.) A presumption of juror misconduct is rebutted "if the entire record in the . . . case, including the nature of the misconduct . . . , and the surrounding circumstances, indicates there is no reasonable probability of prejudice, i.e., no substantial likelihood that one or more jurors were actually biased against the defendant. " (In re Hamilton, supra, 20 Cal.4th at p. 296; People v. Danks, supra, 32 Cal.4th at p. 303.) Factors to consider in making this determination include "the nature of the juror's conduct, the circumstances under which the extraneous information was obtained, the instructions the jury received, the nature of the evidence and issues at trial, and the strength of the evidence against the defendant." (In re Carpenter (1995) 9 Cal.4th 634, 654.)