Calling a Juror Back to Testify About the Verdict

Can you call jurors back to testify about the way a decision was made or about how they didn't really agree, but they acquiesced because of pressure from other jurors?

No (at least not in Virginia), unless the juror is going to testify about an influence from outside the evidence provided in court.

Research that I did on this point a couple weeks back:
 

A. Lord Mansfield's Rule (Common Law Rule): 

 No inquiry allowed as to jury deliberations.

Vaise -v- Delaval, 1 T.R. 11, 99 Eng. Rep. 944 (K.B. 1785):  The court refused to receive affidavits from two jurors indicating that they had decided on their verdict by tossing a coin to resolve the issue. The court cannot receive an affidavit from a juror as to the nature of the juror’s deliberations.

B. Previous Common Law Rule (no longer in effect since 1785):

Allowed as to (1) misbehavior or (2) partiality.

 Norman v. Benmont Willes, 484, 125 Eng. Rep. 1281 (C.P 1744):  “In cases of this sort where the objection could not appear of record, we always admitted of affidavits-as in respect to a misbehavior of any of the jury, or any declaration made by any of them, either before or after the verdict to show that a jury man was partial."

B. Virginia Rule:

Steptoe v. Flood's Adm'r, 72 Va. 323 (1879):  It is certainly a general rule that affidavits of jurors to impeach their verdict should be rejected, first, because they would tend to defeat their own solemn acts under oath; second, because their admission would open a door to tamper with jurymen after they have given their verdict; and third, because they would be the means, in the hands of a dissatisfied juror, to destroy a verdict at any time after he had assented to it. 

Clark v. Commonwealth, 135 Va. 490 (1923):  [I]f each juror gave his assent to this verdict, the accused had no right to inquire how or why he arrived at it. The deliberations of the jury and the motives which actuate them in arriving at a verdict are secret and usually even jurors themselves will not be allowed to impeach their verdict by testimony as to secret motives which controlled them, or misunderstanding instructions of the court, the effects of the evidence, the measure of their verdict and the like.

Federal Deposit Ins. Corp. v. Mapp's Ex'r, 184 Va. 970 (1946):  The testimony of jurors concerning their deliberations and proceedings is not admissible. It is not competent for a juror to testify what did or did not influence him.

Fuller v. Commonwealth, 190 Va. 19 (1949):  [A]fter the discharge of the jury a juror will not be heard to impeach the verdict to which he has agreed by saying that he misunderstood the instructions of the court.

Mir Aimal Kasi v. Commonwealth, 256 Va. 407 (1998):  Virginia has been more careful than most states to protect the inviolability and secrecy of jury deliberations, adhering to the general rule that the testimony of jurors should not be received to impeach their verdict, especially on the ground of their own misconduct. Generally, we have limited findings of prejudicial juror misconduct to activities of jurors that occur outside the jury room.

C. Exceptions to Virginia Rule

(1) Externally Acquired Evidence:

Evans-Smith v. Commonwealth, 5 Va. App. 188 (1987)(Juror consulted an almanac): Generally, the testimony of jurors ought not to be received to impeach their verdict, especially on the ground of their own misconduct. . . . An exception to the general rule limiting post-verdict examination of jurors is recognized when it appears that matters not in evidence may have come to the attention of one or more jurors so as to violate the defendant's constitutional right to be confronted with the witnesses against him.

See also: Harris v. Commonwealth, 13 Va. App. 47 (1991)(Juror, a prison guard, “testified” to fellow jurors about the effects of parole on a sentence from a position of knowledge and authority)

(2) Discussing the Case With a Non-Juror

Caterpillar Tractor Co. v. Hulvey, 233 Va. 77 (1987):  Generally, we have limited findings of prejudicial juror misconduct to activities of jurors that occur outside the jury room. For example, the rule has been applied to expressions of opinion made by a juror to third persons during trial proceedings. In most cases, misconduct outside the jury room has prejudicially affected the jury's deliberation of the case by injecting facts connected with the case which had not been admitted in evidence. For example, the rule has been applied to an improper jury view and to unauthorized private conversations between jurors and third persons. 

See also:  Jenkins v. Commonwealth, 244 Va. 445 (1992)(adopting same rule in criminal cases)