Research into the way in which jurors and juries make decisions during trials in court is highly important within both psychology and law. However, many difficulties arise when conducting this research. Due to jurors being sworn to secrecy about the case they are involved in, mock trials take place in research. This leads to assumptions being made about stages of decision making as we cannot enter the jury room during a real trial, reducing the reliability and ecological validity of such research.
Hastie et al. (1983) described the stages of decision making that take place amongst members of a jury. Perhaps the stages described don’t occur within a real jury, as the pressure of being locked in a room until a decision is made may be greater in a real jury than a jury for a mock trial. However, we can neither prove nor disprove that these stages take place, although it seems highly likely that they do.
Research has shown that the type of evidence presented can have a massive impact on the decisions that jurors make about the verdict of the defendant. Again though, this research is conducted with mock jurors, reducing the reliability and ecological validity. For example, gruesome evidence has been shown to increase the likelihood of a guilty verdict being given (Bright & Goodman-Delahunty, 2006). This is probably due to higher levels of anger and emotion in mock jurors who saw the gruesome evidence compared to jurors who did not see the evidence.
The order in which evidence is given has also been shown to have an effect upon the verdict given by the jury (Pennington & Hastie, 1988). It was found that evidence presented in story order, rather than in witness order, has a greater impact and this is more so when the evidence is from the prosecution. This research has some ecological validity because the case presented was adapted from a real-life case. However, participants were paid to take part and were university students, so the results cannot be generalised to a real jury, as it would be made up of a variety of different people and real jurors do not get paid for their service.
Overall though, research into decision making within a jury is highly important. Although studies often lack reliability, ecological validity and the ability to be generalised, they can highlight important issues in which the way evidence is presented affects the decision made, and also the stages jurors go through to reach their verdict, making them very useful. The usefulness of these studies, I believe, is more important than the levels of ecological validity and reliability. This is because highlighting these influences can lead to important changes that are needed in order to make trials fair for defendants and allow a reasonable verdict to be reached from the appropriate evidence. If changes were not made, a person’s life may be negatively affected by the verdict reached, whether this is the defendant or victim, as the wrong verdict may be reached.
References:
Bright, D. A., & Goodman-Delahunty, J. (2006). Gruesome evidence and emotion: Anger, blame and jury decision-making. Law and Human Behaviour, 30, 183-202. doi: 10.1007/s10979-006-9027-y
Hastie, R., Penrod, S. D., & Pennington, N. (1983). Inside the Jury. Cambridge, Mass.: Harvard University Press.
Pennington, N., & Hastie, R. (1988) Explanation-based decision making: Effects of memory structure on judgment. Journal of Experimental Psychology: Learning, Memory, and Cognition, 14, 521-533. doi: 10.1037/0278-7393.14.3.521
gfsbp 
There are many extraneous variables in jury decision making, which makes this topic a hard one to study. As you said, mock trials have to be used because of the confidentiality policy jurors have to sign. The major problem with mock trials is that they consist of volunteers (wanting to be a part of a psychological study). Therefore, volunteer bias would be apparent here. This is different to an actual jury, as if you are called to jury, you have to take part (unless you have legitimate reasons not to do so). This therefore means that some people may not get involved or they may not care what the outcome of the trial is. Therefore, similar to what you said, mock trials are not a true justification of real trials and juries. They would therefore lack generalisability and validity. Juries can be extremely subjective, too. They could relate to their own experiences when coming to a verdict and therefore manipulate the verdict based on their experiences. The question here is therefore is it right for the verdict to be down to the jury? Or should we adopt a different legal system? However, in research, sometimes there is only so far researchers can go and it is likely that evaluating and observing mock trials is the closest they can get to observing how people behave in a jury setting.
As you pointed out most studies into this area have been done using mock trials, which lack ecological validity possibly causing the results to be unreliable and invalid. However you didnt mention the fact that during a real trial the jurors are being asked to decide if someone is guilty or not and this decision can have a real impact on the defendants life, if for example they were being sentenced to life in prison. This idea can weigh on the jurors minds and effect their final decisions, this cannot be explored using mock trials because the outcome hasnt got a dramatic effect on someones life. Also when conducting research for our writing for science essay i came across some research that suggested that victims who are attractive tend to be given more compensation and their attackers received higher sentences due to the fact the jurors found them more likeable and friendly (Stephan and Tully, 1977). So there are many things that influence a jurys decisions and in some cases the reasons arent relevant to the crimes and some times they are influence by the possible consequences of their decisons.
Although these studies have all been mock trials which as you mentioned carry many flaws, without this research we would be oblivious to the factors outside the evidence that influence a juries decision. Factors that are completely unrelated to the case have been shown to affect the juries decision such as the attractiveness of the defendant. Saladin et al (1988) found that not only were attractive defendants viewed more sympathetically they were considered to be less likely to be guilty by mock jurors. Other factors such as the race of the victim and the defendant also play huge roles in determining the juries decision (Stewart 1980, Skolnick and Shaw 1997, Pfieifer and Ogloff 1991). Research such as this, albeit they have flaws, but they still provide crucial evidence into factors that affect a jury outcome that shouldn’t. Now that we are aware of these issues we can attempt to diminish these effects in the courtroom and make jury decision making more reliable and solely based on facts and not other unrelated factors.
Many things could alter a juror’s view of the crime and therefore their decision of whether the defendant is guilty or not guilty. Conformity is something that may have an effect on their decision, if everyone but one person on the jury believes that the defendant is guilty it’s probable that the one person who believes that the defendant is not guilty may say that they believe the defendant is guilty. The discussion with other jurors may also alter their view, they may have formed their own opinion when they were presented the evidence but other people’s interpretation may change their view. More research should be done to see what effects the juror’s personal opinion.
I agree that research into jury duty is very important as I have been ‘lucky’ enough to be selected to do it. The case I was put on involved a mugging and at first I was apathetic towards the case. But then the person who was mugged came to the stand and told the story of how they were brutally attacked and chased then held at knife point. They described their emotions at the time and how scared they were. After hearing the story, I was genuinely angry towards the people in question and after reading your blog I can see now that listening to evidence in story form is very effective (Pennington & Hastie, 1988).
Further research can be done perhaps in order to give the prosecution or defence a better change of winning the case. A good lawyer may read this research and gain an advantage in the court room when presenting evidence. Although it is not only how the evidence is presented which can have an effect on the jury. Devine et al (2001) shown that Numerous factors were found to have consistent effects on jury decisions: definitions of key legal terms, verdict/sentence options, trial structure, jury-defendant demographic similarity, jury personality composition related to authoritarianism/dogmatism, jury attitude composition, defendant criminal history, evidence strength, pretrial publicity, inadmissible evidence, case type, and the initial distribution of juror verdict preferences during deliberation.
Devine, D. J., Clayton, L. D., Dunford, B. B., Seying, R., Pryce, J. (2001). Jury Decision Making: 45 Years of Empirical Research on Deliberating Groups. Psychology, Public Policy and Law. 7 (3), 622-727.
Pennington, N., & Hastie, R. (1988) Explanation-based decision making: Effects of memory structure on judgment. Journal of Experimental Psychology: Learning, Memory, and Cognition, 14, 521-533. doi: 10.1037/0278-7393.14.3.521
I agree that further research needs to be done but the level of unreliability is overwhelming, especially in situations that change lives so suddenly and rapidly, most of the time in a negative way. Because the jury are not constantly in these positions as they are not by proffesion designed to convict and judge, it is very unreliable to carry out research in practise trials.
This is an interesting area of psychology; in fact my friend did his dissertation on this. He asked a participant to act as someone giving evidence. This was in front of other participants and was also being recorded at the same time. My friend then played the tape to other participants and both groups were asked if they thought the person giving evidence was telling the truth and was trustworthy. My friend found that the participants who viewed the recording felt he was far less trustworthy and less inclined to believe him compared to the group who were present at the time of the recording. This has implications in a variety of cases that uses video technology during eye witness testimony (often to protect the person giving evidence).