OPINION

Respondent Ana M. Olivarez appeals the district court’s order granting, in part, California state prisoner William Mancuso’s 28 U.S.C. § 2254 habeas petition on the ground of juror misconduct. Mancuso cross-appeals the district court’s denial of five of his remaining claims for relief. We have jurisdiction under 28 U.S.C. §§ 1291 & 2253. Because we deny the habeas corpus relief awarded by the district court as to the juror misconduct claim, we reverse, in part, and affirm the remainder of the district court’s order.

I

Mancuso was convicted in 1980 of first degree murder and robbery. The California Court of Appeal summarized the facts surrounding the murder as follows:

People v. Mancuso, No. 3 Crim. 10984 (Cal.Ct.App. Nov. 4,1982) (order affirming conviction).

Mancuso’s jury trial lasted more than one month. During that time, the jury heard thirty-one days of testimony from more than one hundred witnesses. In support of its case, the State presented the following evidence against Maneuso: eyewitness testimony of Dale King; testimony regarding Mancuso’s efforts to construct a silencer; testimony of Marcie Crooks, a student intern with the Sacramento County Sheriffs Department, to the effect that Maneuso was carrying a handgun on the night of the murder; testimony regarding Mancuso’s post-arrest attempts to destroy evidence; and the fact that the handgun used to kill Thomas was found in Mancu-so’s car after the murder.

In his defense, Maneuso testified that he had been a witness to the Tradewinds killing, and that Stephen Christensen had committed the crime. He also alleged that he was being framed by Christensen, and co-conspirators King and Lequeta Thomas. The United States Magistrate Judge summarized the details of Mancu-so’s defense as follows:

Mancuso v. Olivarez, No. 96-0787 (E.D.Cal. April 12, 2000) (Findings and Recommendation).

On the twelfth day of testimony, evidence of Mancuso’s parole status was inadvertently admitted over the court’s prior in limine order. Defense counsel moved for a mistrial. The motion was denied and the jury was instructed to disregard the inadmissible testimony.

On May 28, 1980, the jury began its 7-day deliberation. On the second day, the jury requested that the testimony of King and Mancuso be read back to them. After several days of re-reading, the jury requested that additional testimony be reread and made a further inquiry.

The jury found Mancuso guilty of first-degree murder and robbery on June 5, 1980. It also found the following four special circumstances “Not True”: 1) that the murder of Thomas was willful, deliberate and premeditated; 2) that Mancuso was personally present during the commission of the act or acts causing death; 3) that Mancuso, with the intent to cause death, physically committed the act or acts causing death; and 4) that the murder was committed while Mancuso was engaged in the commission of a robbery.

After the jury verdict, defense counsel moved for a new trial on several grounds, including juror misconduct. That motion was denied, and Mancuso appealed. The Third Appellate District of California rejected Mancuso’s juror misconduct claim, among others, and affirmed his conviction. The California Supreme Court denied review without comment.

Between 1986 and 1996, Mancuso filed two habeas petitions in federal district court. Both petitions were dismissed for failure to exhaust state court remedies. Mancuso apparently continued to exhaust his claims in the California state courts. Mancuso filed the present petition on April 19, 1996. The petition was amended on September 13, 1996, and was assigned to United States Magistrate Judge Dale Drozd for findings.

Judge Drozd filed his Findings and Recommendations in April 2000, recommending that the district court grant Mancuso rebef on the juror misconduct claim and deny relief on the remaining eight claims. Chief United States District Judge Lawrence Karlton adopted the Findings and Recommendations in their entirety. This appeal and cross-appeal followed.

II

We review de novo the district court’s decision to grant or deny a petition for a writ of habeas corpus. See DePetris v. Kuykendall, 239 F.3d 1057, 1061 (9th Cir.2001). We also review de novo the issue of juror misconduct, see Sassounian v. Roe, 230 F.3d 1097, 1108 (9th Cir.2000), and claims of ineffective assistance of counsel, see Jackson v. Calderon, 211 F.3d 1148, 1154 (9th Cir.2000), cert. denied, 531 U.S. 1072 , 121 S.Ct. 764 , 148 L.Ed.2d 665 (2001). The district court’s factual findings, however, are reviewed for clear error. See Solis v. Garcia, 219 F.3d 922, 926 (9th Cir.2000), cert. denied, — U.S.—, 122 S.Ct. 94 , 151 L.Ed.2d 55 (2001).

Substantive review of this petition is governed by pre-Antiterrorism and Effective Death Penalty Act of 1996 (“AED-PA”) standards and precedent because Mancuso filed his petition prior to the effective date of AEDPA. See Lindh v. Murphy, 521 U.S. 320, 327 , 117 S.Ct. 2059 , 138 L.Ed.2d 481 (1997); Sassounian, 230 F.3d at 1105 .

III

Mancuso claims his Sixth Amendment right to a fair and unbiased jury was violated when the jury was exposed to prejudicial extrinsic information during the trial and during jury deliberation. He specifically contends that: 1) at trial, a witness improperly referred to a parole search of Mancuso’s apartment; and 2) during jury deliberations, the foreperson announced his belief that Mancuso had committed a prior felony, or felonies, which information he gained after tampering with a trial exhibit. Because credibility determinations were dispositive in this case, Mancu-so asserts that the improper reference to the “parole search” coupled with the foreman’s misconduct undermines the reliability of the verdict.

Under the Sixth Amendment, Man-cuso has a federal constitutional right to an impartial jury, the right to confront those who testify against him, and the right to conduct cross-examination. See Duncan v. Louisiana, 391 U.S. 145, 149 , 88 S.Ct. 1444 , 20 L.Ed.2d 491 (1968) (Sixth Amendment right to jury trial); Pennsylvania v. Ritchie, 480 U.S. 39, 51 , 107 S.Ct. 989 , 94 L.Ed.2d 40 (1987) (Sixth Amendment right to confront witnesses and conduct cross-examination); Turner v. Louisiana, 379 U.S. 466, 472-73 , 85 S.Ct. 546 , 13 L.Ed.2d 424 (1965) (Sixth Amendment right to trial by jury in which the jury verdict is based on evidence produced at trial).

On habeas review, Mancuso has the burden of establishing that the extrinsic evidence had a substantial and injurious effect or influence in determining the jury’s verdict. See Brecht v. Abrahamson, 507 U.S. 619, 623 , 113 S.Ct. 1710 , 123 L.Ed.2d 353 (1993) (holding that to obtain habeas corpus relief a petitioner must demonstrate that the state court erred and that such error was prejudicial because it had a substantial and injurious effect on the jury’s verdict); Thomas v. Hubbard, 273 F.3d 1164, 1170 (9th Cir.2001) (as amended) (same); Sassounian, 230 F.3d at 1108 (same). In determining whether the error had a substantial and injurious effect, the Supreme Court has long held that:

Kotteakos v. United States, 328 U.S. 750, 765 , 66 S.Ct. 1239 , 90 L.Ed. 1557 (1946). See also Jeffries v. Blodgett, 5 F.3d 1180, 1190 (9th Cir.1993) (same).

No bright line test exists to assist courts in determining whether a petitioner has suffered prejudice from juror misconduct. See Rodriguez v. Marshall, 125 F.3d 739, 744 (9th Cir.1997). We therefore “place great weight on the nature of the extraneous information that has been introduced into deliberations.” Id. (citing Jeffries v. Wood, 114 F.3d 1484, 1490 (9th Cir.1997)). See Thompson v. Borg, 74 F.3d 1571, 1574 (9th Cir.1996) (juror misconduct occurs when a juror introduces into the jury’s deliberation a matter which was not in evidence or in the instructions). The potential for prejudice is heightened when a juror interjects into the deliberations “objective extrinsic facts” regarding the accused because that juror becomes an unsworn witness who is not subject to either confrontation or cross-examination. Jeffries v. Wood, 114 F.3d at 1490 . See United States v. Navarro-Garcia, 926 F.2d 818, 821-22 (9th Cir.1991) (holding that a juror’s personal knowledge or experience constitutes extrinsic evidence where the juror interjects his or her past personal experiences into deliberations in the absence of any record evidence on a given fact). While jurors may bring their life experiences to a case “it is clearly improper for jurors to decide a case based on personal knowledge of facts specific to the litigation.... ” Hard v. Burlington N. R.R., 870 F.2d 1454, 1462 (9th Cir.1989) (denying new trial where one juror used personal knowledge of x-ray interpretation to sway others because “[i]t is expected that jurors will bring their life experiences to bear on the facts of a case”).

Here, the trial court prohibited the use or introduction of evidence regarding Man-cuso’s prior felony convictions or parole status at trial. The prosecution advised its witnesses accordingly. Nevertheless, Detective Gary Gritzmacher, the prosecutor’s lead investigator on the Thomas murder, stated during cross-examination that he participated in a “parole search” at Mancu-so’s apartment. The trial judge had previously instructed Gritzmacher to simply state “yes” or “no” in response to the defense attorney’s question. After Gritz-macher’s inappropriate response, the trial judge called a recess.

Outside the presence of the jury the trial judge reprimanded Detective Gritz-macher. He questioned the propriety of Gritzmacher’s response after he had been explicitly instructed not to mention that Mancuso was on parole. The trial judge stated that Gritzmacher’s reference to a “parole search” indicated to the jury that Mancuso was an ex-felon and could possibly have “destroy[ed] four months of work that’s gone into this case.” He then surmised that “[t]he officer’s failure to follow instructions ha[d] jeopardized the entire trial.” Nevertheless, the trial judge denied Mancuso’s motion for a mistrial, and carefully instructed the jury to ignore Gritzmacher’s statement.

Later in the trial, after Mancuso had testified, the prosecution sought to admit evidence of Mancuso’s prior robberies. The trial judge denied the prosecutor’s motion out of concern that admission of such evidence would ensure a guilty verdict based not on twenty-five days of testimony from over one hundred witnesses, but “on the one question of whether Mr. Mancuso has a bad character or not.” Specifically, the trial judge stated:

Transcript at 9539 (emphasis added).

After receiving instructions, the jury began its deliberation. On the second day of deliberations, the jury requested that all admitted exhibits be sent into the jury room, with the exception of a firearm and the currency. Mancuso’s counsel objected to sending in the photograph of Christensen. Christensen’s photograph had been admitted into evidence with the booking numbers covered with tape. The photograph of Mancuso was admitted into evidence with the booking numbers exposed. The trial judge sent the exhibits to the jury as they had been admitted into evidence.

During the course of the jury’s deliberations Foreman Fitzgerald informed his fellow jurors that Mancuso had been convicted of a felony (or felonies) long ago. Foreman Fitzgerald deduced this fact by removing the tape at the bottom of the photograph of Christensen and comparing the Sacramento County Jail booking numbers on the bottom of Mancu-so and Christensen’s photographs. While Mancuso and Christensen had been arrested and booked on the same date, Mancu-so’s booking numbers were apparently lower. Fitzgerald believed the difference in the numbers reflected the fact that Mancuso had a longer record than Christensen. Foreman Fitzgerald gleaned this information from the booking numbers based upon his prior employment as a youth counselor with the California Department of Corrections.

A juror’s personal knowledge of specific information concerning the defendant or the defendant’s alleged crime constitutes impermissible extrinsic evidence. See Jeffries v. Blodgett, 5 F.3d at 1190 n. 2 (citing Navarro-Garcia, 926 F.2d at 821 ). See also Jeffries v. Wood, 114 F.3d at 1490 . Here, Foreman Fitzgerald injected personal knowledge of facts specific to Mancu-so that were not a part of the record. Such evidence was extrinsic to this case.

In order to determine whether the introduction of such extrinsic evidence constitutes reversible error, however, we consider the following factors:

Bayramoglu v. Estelle, 806 F.2d 880, 887 (9th Cir.1986), quoted in Jeffries v. Blodgett, 5 F.3d at 1190 (stating that “none of these factors should be considered disposi-tive”).

In this case, the extrinsic evidence — the testimony regarding the “parole search” and Foreman Fitzgerald’s conclusion regarding the booking numbers — was actually received by the entire jury. The reference to Mancuso’s parole status was made on the twelfth day of thirty-one days of testimony, and the fact that Mancuso had a felony conviction was shared with the jury during its seven-day deliberation. Foreman Fitzgerald and Juror Anthony Taylor’s affidavits further indicate that the jury did not discuss the extrinsic material at great length, but that such material was introduced before the verdict was entered.

Thus, it is the fifth factor that is determinative in this case — were there any other matters which may bear on whether the introduction of extrinsic material substantially and injuriously affected the verdict? Within the fifth factor, we conduct the following inquiries:

United States v. Keating, 147 F.3d 895, 902-03 (9th Cir.1998) (footnote omitted); Jeffries v. Wood, 114 F.3d at 1491-92 .

First, we consider the evidence regarding Detective Gritzmacher’s reference to a “parole search.” Gritzmacher’s statements were not ambiguous nor cumulative of other evidence adduced at trial. See Eslaminia v. White, 136 F.3d 1234, 1239 (9th Cir.1998) (“[T]o be truly considered cumulative, there must be an extremely close relationship between the extrinsic evidence and the evidence actually admitted.”). The jury was carefully admonished, however, to ignore Gritz-macher’s statement and there is a strong presumption that the court’s curative instruction was followed by the jury. See Doe ex rel. Rudy-Glanzer v. Glanzer, 232 F.3d 1258, 1270 (9th Cir.2000). In addition, the curative instruction was provided in the context of thirty-one days of testimony from more than one hundred witnesses. Any prejudice that might have occurred as a result was diluted by the copious testimony and satisfactorily ameliorated by the curative instruction.

[4] The foreman’s statements, while also unambiguous and not otherwise admissible, could not be cured with an instruction. We must therefore consider the fifth inquiry: whether the statement was insufficiently prejudicial given the issues and evidence in the case. We conclude that it was. Juror misconduct cases in which habeas relief has been granted often involve the jury’s receipt of information excluded from trial as unduly prejudicial such as evidence of the facts surrounding a defendant’s prior conviction, bad reputation, or propensity to violate the law. See Rodriguez, 125 F.3d at 744 . In all cases, the reviewing court must apply an objective test in evaluating the potential impact of the evidence on the jury. See id.; Jeffries v. Blodgett, 5 F.3d at 1191.

The appropriate inquiry is whether there was a direct and rational connection between extrinsic material and the prejudicial jury conclusion, and whether the misconduct relates directly to a material aspect of the case. See Rodriguez, 125 F.3d at 744 ; Jeffries v. Blodgett, 5 F.3d at 1190 ; Dickson v. Sullivan, 849 F.2d 403, 406 (9th Cir.1988). Cf. Lawson v. Borg, 60 F.3d 608 (9th Cir.1995) (granting the petition where a juror improperly told the jury that the defendant was violent); Jeffries v. Blodgett, 5 F.3d at 1191 (granting the petition where the jury learned that the defendant had previously committed armed robbery); Dickson, 849 F.2d at 408-09 (granting the petition after jurors were told that the defendant, on trial for bludgeoning a man to death with a pool cue, had “done something like this before”).

Here, the jury never learned the prejudicial details of Mancuso’s criminal history (e.g., that Mancuso’s criminal record included three or four other robberies). They were told only that the foreman believed that both Christiansen and Mancuso had a criminal history, that Mancuso had been convicted of a felony, or felonies, “some time ago,” and that Mancuso might have had a longer record than Christian-sen. These general assertions were not substantial and injurious in the overall context of this trial. Moreover, the trial judge, who was aware of the prejudicial possibility of Mancuso’s criminal record and took steps to prevent such evidence from going to the jury, did not believe a new trial was warranted after listening to all the evidence including the evidence of juror misconduct. See United States v. Hanley, 190 F.3d 1017, 1031 (9th Cir.1999) (stating that special deference is accorded to the trial judge’s impression of the impact of alleged juror misconduct).

There is no doubt that the jury’s assessment of Mancuso and King’s credibility was critical to its decision. In applying the objective standard in the context of this trial, however, we hold that the testimony regarding the parole search coupled with consideration of extraneous evidence that petitioner had a felony record did not have a substantial and injurious influence on the jury’s verdict. Because we hold that the jury’s consideration of such extrinsic evidence was not unduly prejudicial in relation to the issues in this case, we reverse the district court’s decision to grant the writ on this ground.

IV

Petitioner also claims his trial counsel was ineffective because she agreed to withhold from the jury the fact that witnesses had been hypnotized and because she failed to impeach a witness for bias.

In order to succeed on an ineffective assistance of counsel claim, a petitioner must demonstrate that counsel’s representation was deficient and that such deficiency prejudiced his or her defense. See Strickland v. Washington, 466 U.S. 668, 687 , 104 S.Ct. 2052 , 80 L.Ed.2d 674 (1984). Counsel’s representation is considered deficient when his or her performance falls below “reasonableness under prevailing professional norms.” Id. at 688 , 104 S.Ct. 2052 . This standard requires that courts be deferential to counsel by making “every effort ... to eliminate the distorting effects of hindsight, to reconstruct the circumstances of counsel’s challenged conduct, and to evaluate the conduct from counsel’s perspective at the time.” Id. at 689 , 104 S.Ct. 2052 .

Consistent with such deference is the “strong presumption that counsel’s conduct falls within the wide range of reasonable professional assistance.” Id. Defendants must also overcome “the presumption that, under the circumstances, the challenged action might be considered sound trial strategy.” Id. (internal quotations omitted). See also Murtishaw v. Woodford, 255 F.3d 926, 939 (9th Cir.2001) (stating that the defendant “bears the heavy burden of proving that counsel’s assistance was neither reasonable nor the result of sound trial strategy”).

Mancuso cannot overcome these presumptions. First, he contends he was deprived of his Sixth Amendment right to effective assistance of counsel when defense counsel agreed to withhold from the jury the fact that witnesses King and Crooks had been hypnotized. He argues that his counsel should have drawn upon the “wealth of expert opinion” available at that time in support of the proposition that hypnosis was not a guarantee of truth.

Prior to trial, defense counsel moved to exclude any reference to that fact that King and Crooks had been hypnotized. The government so stipulated. In addition, the trial judge remarked that if the parties had not so stipulated, he would have entered such an order, in light of the potential danger that the jury might assume that statements made while under hypnosis were more truthful than other statements. Fearing this prejudice, defense counsel chose to exclude all references to hypnosis. In fact, on the record, Mancuso’s counsel agreed with the trial judge that the fact of King’s hypnosis “in the mind of the trier of fact ... would be almost a guarantee of truth.”

Both defense counsel and the trial judge believed that the jury would presume that statements made under hypnosis were truthful. It was agreed that this would lend unwarranted credibility to such testimony. Mancuso nevertheless contends defense counsel should have worked to overcome the jury’s presumptions and misconceptions regarding hypnosis, particularly in light of the abundance of information regarding the unreliability of hypnosis.

As stated above, Mancuso’s counsel’s decisions are entitled to deference. We will not second-guess such decisions or use hindsight to reconstruct the circumstances of counsel’s challenged conduct. See Strickland, 466 U.S. at 688 , 104 S.Ct. 2052 ; Guam v. Santos, 741 F.2d 1167, 1169 (9th Cir.1984) (stating that a “tactical decision by counsel with which the defendant disagrees cannot form the basis of a claim of ineffective assistance of counsel”). Mancu-so’s argument that his counsel could have presented a better defense fails to overcome the strong presumption that counsel’s conduct fell within the wide range of reasonable professional assistance. In light of the record and facts in this case, defense counsel made a reasonable and sound strategic choice to eliminate any references to King and Crooks’ hypnosis sessions.

Mancuso also contends he was deprived of his Sixth Amendment right to effective assistance of counsel when his trial counsel failed to impeach Crooks for bias. Crooks was an intern at the Sacramento County Sheriffs Department and had been involved in the Mancuso investigation. Mancuso asserts counsel should have “used this information to highlight Crooks’ occupational motive and interest in changing her testimony to conform to the suggestions from officers.”

Mancuso’s contention is unconvincing. During cross-examination Crooks stated that she was a student intern with the Sheriffs Department and that she wished to “help solve the case.” Defense counsel also brought out the fact that Crooks did not mention in her original statement to the detectives that she had seen the outline of an automatic weapon in Mancuso’s jacket pocket, but that she was now testifying to such facts.

Defense counsel’s cross-examination and impeachment of Crooks’ credibility placed her performance well within the wide range of professional assistance demanded of criminal attorneys. Again, Mancuso’s suggestions regarding how defense counsel might have handled Crooks’ cross-examination differently are insufficient to support an ineffective assistance of counsel claim.

We therefore affirm the district court’s denial of petitioner’s ineffective assistance of counsel claims.

V

Mancuso asserts that the use of posthypnotic testimony deprived him of his Sixth Amendment right to confront the witnesses against him. He contends that the hypnotic process itself undermines the ability to reliably test a witness’ veracity on cross-examination because it hardens the witness’ memories, whether or not such memories are uncertain or false. Because such memories remain unconscious, Mancuso asserts confrontation is impossible.

We have previously rejected this argument. The admission of post-hypnotic testimony does not violate the Sixth Amendment right to confrontation. See United States v. Awkard, 597 F.2d 667, 669 (9th Cir.1979) (holding “[t]he fact of hypnosis, if disclosed to the jury, may affect the credibility of evidence, but not its admissibility”); United States v. Adams, 581 F.2d 193, 198 (9th Cir.1978) (stating “that the fact of hypnosis affects credibility but not admissibility”). The United States Supreme Court has held, in the context of a previously hypnotized defendant, that “traditional means of assessing accuracy of testimony ... remain applicable.” Rock v. Arkansas, 483 U.S. 44, 61 , 107 S.Ct. 2704 , 97 L.Ed.2d 37 (1987). Thus, “[c]ross-ex-amination, even in the face of a confident defendant, is an effective tool for revealing inconsistencies.” Id.

Mancuso’s argument that admission of post-hypnotic testimony itself is violative of his Sixth Amendment rights to confrontation and cross-examination has been rejected by this Circuit. The admissibility of such evidence, in general, has been upheld by the Supreme Court. We therefore affirm the district court’s denial of Mancu-so’s Sixth Amendment Confrontation Clause claim.

VI

Mancuso contends that the admission of King’s unreliable post-hypnotic testimony violated his due process rights.

The Due Process Clause guarantees every defendant the right to a trial that comports with the basic tenets of fundamental fairness. See Lassiter v. Dep’t of Soc. Servs., 452 U.S. 18, 24-25 , 101 S.Ct. 2153 , 68 L.Ed.2d 640 (1981). A writ of habeas corpus will be granted for an erroneous admission of evidence only where the “testimony is almost entirely unreliable and ... the factfinder and the adversary system will not be competent to uncover, recognize, and take due account of its shortcomings.” Barefoot v. Estelle, 463 U.S. 880, 899 , 103 S.Ct. 3383 , 77 L.Ed.2d 1090 (1983).

Thus, in order to establish a due process violation based on the admission of erroneous evidence, Mancuso “must show that that error rendered the trial so ‘arbitrary and fundamentally unfair’ that it violated federal due process.” Pennywell v. Rushen, 705 F.2d 355, 357 (9th Cir.1983) (quoting Powell v. Spalding, 679 F.2d 163, 166 (9th Cir.1982)).

As stated previously, at the time of Mancuso’s trial, testimony based upon memories refreshed under hypnosis was admissible. See Rock, 483 U.S. at 44 , 107 S.Ct. 2704 ; Awkard, 597 F.2d at 669 ; Adams, 581 F.2d at 198 . Because the admission of hypnotically refreshed evidence is not at issue in this Circuit, “there is no need for a foundation concerning the nature and effects of hypnosis.” Awkard, 597 F.2d at 669 . We have specifically rejected the constitutional argument that “the in-court testimony of a witness who had earlier been subject to hypnosis is unreliable as a matter of law....” Adams, 581 F.2d at 199 .

Nevertheless, this Circuit has recognized that “[gjreat care must be exercised to ensure that statements after hypnosis are the product of the subject’s own recollections, rather than of recall tainted by suggestions received while under hypnosis.” Id. at 198-99 (finding that “investigatory use of hypnosis on persons who may later be called upon to testify in court carries a dangerous potential for abuse”).

The only procedural requirement in this Circuit, however, is that a complete stenographic record of the hypnosis interview be maintained. Id. at 199 n. 12. Cf. Rock, 483 U.S. at 60-61 , 107 S.Ct. 2704 (suggesting the following procedural safeguards to reduce the inaccuracies that hypnosis induces: that hypnosis be performed by a psychologist or psychiatrist; that such person have special training and be independent of the investigation; that the hypnosis occur in a neutral setting; and that no one be present except the subject and the hypnotist). Thus, if the hypnosis interview has been properly recorded and maintained, and the foundation of post-hypnotic testimony remains in question, it is the defendant’s burden to challenge the adequacy of the foundation. See Adams, 581 F.2d at 199 .

Here, defense counsel made a strategic choice to eliminate all references to King and Crooks’ hypnosis sessions, thereby preventing her from challenging the foundation of the hypnosis sessions themselves. She did, however, challenge the reliability, or credibility, of King’s testimony during her cross-examination. Defense counsel was therefore able to impeach King’s testimony without reference to the hypnosis session.

The fact that defense counsel did not mount the type of attack on post-hypnotic testimony that Mancuso would have liked did not render the trial “so ‘arbitrary and fundamentally unfair’ that it violated federal due process.” Pennywell, 705 F.2d at 357 (quoting Powell, 679 F.2d at 166 ). We therefore affirm the district court’s denial of this claim.

VII

Mancuso contends the prosecution committed misconduct in violation of Man- cuso’s due process rights by knowingly using false testimony based on post-hypnotic memories that were tainted by police coaching.

Prosecutorial misconduct violates a defendant’s due process rights when it “so infected the trial with unfairness as to make the resulting conviction a denial of due process.” Darden v. Wainwright, 477 U.S. 168, 181, 106 S.Ct. 2464 , 91 L.Ed.2d 144 (1986) (quoting Donnelly v. DeChristoforo, 416 U.S. 637, 643 , 94 S.Ct. 1868 , 40 L.Ed.2d 431 (1974)); Bonin v. Calderon, 59 F.3d 815, 843 (9th Cir.1995). “Improper argument does not, per se, violate a defendant’s constitutional rights.” Thompson, 74 F.3d at 1576 (quoting Jeffries v. Blodgett, 5 F.3d at 1191 ).

A prosecutor, however, has a constitutional duty to correct evidence he or she knows is false, even if it was not intentionally submitted. See Giles v. Maryland, 386 U.S. 66 , 87 S.Ct. 793 , 17 L.Ed.2d 737 (1967). Similarly, “a State may not knowingly use false evidence, including false testimony, to obtain a tainted conviction ... merely because the false testimony goes only to the credibility of the witness.” Napue v. Illinois, 360 U.S. 264, 269 , 79 S.Ct. 1173 , 3 L.Ed.2d 1217 (1959). Here, Mancuso contends the prosecutor violated the Due Process clause when he knowingly presented “coached testimony” that “went directly to the credibility of the state’s star witness.” Mancuso relies principally on Napue in support of his contention.

There is no evidence in this case that the prosecutor presented false testimony. Because the parties agreed to exclude evidence of the hypnosis sessions, and the post-hypnotic testimony was properly admitted, it was defense counsel’s burden, not the State’s, to attack the credibility of the State’s witnesses. As stated in Section IV, defense counsel made a strategic choice not to question the foundation of King’s testimony and, instead, illuminated the discrepancies in King’s pre- and posthypnotic testimony and the officers’ “coaching,” on cross-examination.

Although Mancuso contends that cross-examination “cannot expose the manipulation of hypnotic suggestibility if it ignores the fact of hypnosis,” this contention is contrary to the Supreme Court’s ruling in Rock . As stated above, Rock held that “[c]ross-examination, even in the face of a confident defendant, is an effective tool for revealing inconsistencies.” 483 U.S. at 61 , 107 S.Ct. 2704 .

We hold that the prosecutor’s conduct did not rise to the level of a due process violation, and affirm the district court’s denial of this claim.

VIII

Mancuso asserts that the cumulative effect of errors in this case prejudiced his right to a fair trial and warrants a reversal. Cumulative error applies where, “although no single trial error examined in isolation is sufficiently prejudicial to warrant reversal, the cumulative effect of multiple errors may still prejudice a defendant.” United States v. Frederick, 78 F.3d 1370, 1381 (9th Cir.1996). Because there is no single constitutional error in this case, there is nothing to accumulate to a level of a constitutional violation. See Fuller v. Roe, 182 F.3d 699, 704 (9th Cir.1999). We therefore hold there is no cumulative error and affirm the district court’s denial of this claim.

IX

Mancuso was entitled to a fair trial, not a perfect one. See Lutwak v. United States, 344 U.S. 604, 619 , 73 S.Ct. 481 , 97 L.Ed. 593 (1953). We think he received it based on the extensive record adduced in the California courts. He has not established a valid claim for federal habeas relief.

REVERSED, in Part, and AFFIRMED in Part.

. For purposes of this appeal, the state court’s determinations of historical fact are presumed correct. See 28 U.S.C. § 2254 (d) (1994). . According to the district court record, both Mancuso and Christensen were originally charged with Thomas' murder. The State dismissed the charges against Christensen, however, prior to Mancuso’s trial. . There is no dispute that Mancuso has exhausted his state court remedies. . The material that is bracketed in factor five reflects the prejudice standard set forth in Brecht, 507 U.S. at 623 , 113 S.Ct. 1710 . . "The Sixth Amendment guarantees criminal defendants a verdict by impartial, indifferent jurors. The bias or prejudice of even a single juror would violate [a defendant's] right to a fair trial.” Dyer v. Calderon, 151 F.3d 970, 973 (9th Cir.1998). . Of principal import in this inquiry is not whether there was enough evidence to support the verdict, apart from the error, but whether the error itself had a substantial influence on the jury's determination of the verdict. See Kotteakos, 328 U.S. at 765 , 66 S.Ct. 1239 . . While King attended a hypnosis session and later testified at trial, it is unclear whether he was ever actually hypnotized. Because this fact is not critical to our review, we do not resolve this issue. . At the time of Mancuso's trial, post-hypnotic testimony was admissible in California and was not subject to clear procedural safeguards. See People v. Shirley, 31 Cal.3d 18 , 181 Cal.Rptr. 243 , 723 P.2d 1354 (1982); Aguilar v. Alexander, 125 F.3d 815 , 817 (9th Cir.1997) (discussing admissibility of posthypnotic testimony in California prior to 1985).