The concept of jury theory has rather tickled my interest as a layperson and I've ended up down quite a rabbit hole of jury theory research.
There's an interesting discussion regarding the judge's closing remarks to a jury and their comprehension of those remarks influencing which way the verdict goes.
The main studies I have found regarding juries are 'Are Juries Fair?' (2010)
www.justice.gov.uk/downloads/publications/research-and-analysis/moj-research/are-juries-fair-research.pdf
More recent and focusing mainly on the uniquely Scottish verdict of 'not proven', there is the Scottish Government's Scottish Jury Research (2019) - www.gov.scot/news/scottish-jury-research/ which used mock juries in order to undertake the research.
Both studies do make the point about juror comprehension of the points made by the judge. In 'Are Juries Fair', it was noted that a written summary of the judge’s directions on the law given to jurors at the time of the judge’s oral instructions improved juror comprehension of the law. In the Scottish research,various methods are considered in increasing juror comprehension - www.gov.scot/publications/methods-conveying-information-jurors-evidence-review/pages/2/
This thesis is interesting in terms of assessing how introducing 'narrativism' might improve juror comprehension.
orca-mwe.cf.ac.uk/56293/1/Sally%20Nelson%20PhD%20Thesis%20final.pdf
My knowledge of the court system in England and Wales is limited so I found these two parts rather interesting in terms of the jury facing barriers in terms of asking questions or clarifying legal terminology -
'for example, jurors are not permitted
to ask questions directly to witnesses (though they may do so through a written note to the judge), they may not ask questions during the judge’s summing up of the law (though they may subsequently send notes from the jury room), they do not usually have access to a written transcript of the trial in the jury room, and they do not always hear evidence in a temporal, sequential order.'
'This question of comprehensibility of jury instructions in England and Wales
might be more than simply speculative. In R v. Schofield [1993] after giving a verdict
of guilty for affray, one member of the jury told the court usher that the jury had not
understood the meaning of affray and had written a note to that effect but had not
felt able to hand it to the judge. This was to some extent confirmed by the finding of
a note in the jury room reading: ‘we would like a full definition of affray’. It seems
that there was, at least, a real risk that the jury convicted the defendant without
properly understanding the relevant law.'
One thing it mentions which I hadn't realised is that 'formulation of the judges’ instructions in England and Wales is considerably at the discretion of the judge, and regardless of how complex or time consuming it might potentially be, English judges are free to change the wording of their instructions within certain guidelines' - this is referring to the Crown Court Bench Book, which gives guidance rather than instruction and is less prescriptive than the system in US courts. However, I am unsure if the recent publication of the Crown Court Compendium replaces the Bench Book in it's entirety or simply the Specimen Directions of the previous publications.
I thought this was interesting in terms of the difficulties of undertaking research into juries - www.ucl.ac.uk/judicial-institute/sites/judicial-institute/files/myths_misunderstandings_mistakes_powerpoint.pptx