Rape case juries need more guidance from judges because they can "confuse" an emotionless witnesses with a sign of lying, a legal expert has warned.
Cheryl Thomas, professor of judicial studies at UCL, told the House of Commons Home Affairs Committee that a small minority of jury members believe "myths and stereotypes" about complainants.
These include that emotionless complainants are less likely to be telling the truth, and that it is more likely a stranger will rape you rather than someone you know, she said.
Prof Thomas suggested that a potential solution could be judges giving juries "additional guidance" to iron out these points of confusion.
"Judges have the ability to direct juries in relation to rape stereotypes, they receive training on this," said Prof Thomas. "Those directions cover a wide range of issues, whether it’s the way someone dresses or behaves, if it was a late or delayed report, or the level of emotion displayed when giving evidence."
Outlining two "particular issues" which emerged from her research into rape jury attitudes, she said: "We found enough uncertainty on the part of jurors to suggest they may benefit from additional guidance.
"Whether you’re more likely to be raped by a stranger than someone you knew, the overwhelming majority of jurors believed correctly you’re more likely to be raped by someone you knew. But there were enough jurors who were confused and said they weren’t sure, indicating better guidance might be helpful.
"The level of emotion shown while giving evidence: jurors were very split about this. Perhaps some additional guidance might be helpful."
Prof Thomas did not specify how the extra guidance might be delivered to jurors, such as before a trial begins or as a trial progresses.
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She noted that her research shows an incredibly small minority of jurors (less than one person in every jury) hold erroneous beliefs about rape.
These false beliefs include that rapes always leave a victim with marks and bruises, that a victim will always fight back, that the way someone is dressed or their behaviour makes them more likely to be raped, or that the time taken to report a rape has a bearing on whether the complainant is telling the truth, she said.
"We found that contrary to what was found in public opinion polls, those who had served on juries had very, very low levels of belief in commonly held rape myths and stereotypes," she told the committee.
"There has been quite a strong view that juries must be biased against female rape complainants. That’s just not borne out in the research."