Welcome to Your Guide to Criminological Psychology Studies!
In this chapter, we dive into the "real-life" evidence behind criminological theories. Why do we study these? Because in the courtroom and at the crime scene, human memory and behavior are rarely perfect. We will look at a Classic Study that changed how we view eye-witnesses, a Contemporary Study about race in the jury room, and two optional studies looking at stress and pre-trial news. Don't worry if the names and dates seem a bit much—we will break them down into simple stories!
Note: This chapter focuses specifically on the prescribed studies. For the theories behind them, like Reconstructive Memory or Social Learning Theory, please see the "Explanations for crime" and "Eye-witness memory" chapters.
1. The Classic Study: Loftus and Palmer (1974)
"Reconstruction of Automobile Destruction"
The Aim: Elizabeth Loftus and John Palmer wanted to see if the way a question is asked (specifically the leading verb used) could change a person’s memory of a car accident.
Experiment 1: The Speed Estimate
What they did: 45 students watched seven films of traffic accidents. After each film, they were asked: "About how fast were the cars going when they [VERB] each other?"
The participants were split into five groups, each getting a different verb:
1. Smashed
2. Collided
3. Bumped
4. Hit
5. Contacted
The Results: The verb made a huge difference!
- Smashed produced the highest speed estimate: \(40.5\) mph.
- Contacted produced the lowest speed estimate: \(31.8\) mph.
Experiment 2: The Broken Glass
What they did: 150 students watched a film of a multiple-car accident. One group was asked the question with the verb "smashed," one with "hit," and a control group wasn't asked about speed at all. One week later, they were asked: "Did you see any broken glass?" (There was no broken glass in the film).
The Results:
- In the "smashed" group, 16 people said "Yes" to seeing glass.
- In the "hit" group, only 7 said "Yes."
The Conclusion: This is reconstructive memory in action. The information from the leading question (the verb) integrated with the original memory of the accident, creating a new, "fake" memory of broken glass.
Key Takeaway: Leading questions can physically alter our memory of an event. This is why police must be very careful how they interview witnesses!
2. The Contemporary Study: Bradbury and Williams (2013)
"Diversity and Citizen Participation: The Effects of Race on Juror Decision Making"
The Aim: To investigate whether the racial composition of a jury (how many jurors of each race) and the race of the defendant affect whether a person is found guilty.
The Method: Unlike Loftus and Palmer, this was not a lab experiment. The researchers used secondary data. They analyzed 370 real-life trials from various states in the USA, looking at the race of the defendants and the makeup of the juries.
The Results:
- Juries made up of a majority of White jurors were more likely to convict Black defendants.
- Juries made up of a majority of Hispanic jurors were also more likely to convict Black defendants.
- Juries with a higher proportion of Black jurors were less likely to convict Black defendants.
The Conclusion: Jurors are influenced by the race of the defendant. This suggests that "in-group bias" (favoring people who are like you) or "out-group bias" (prejudice against people different from you) plays a role in the legal system.
Did you know? This study is very high in ecological validity because it used real trial data, not a "mock jury" in a classroom!
Key Takeaway: A "fair trial" might be affected by the racial mix of the jury, showing that social factors are just as important as evidence in court.
3. Choice Study A: Valentine and Mesout (2009)
"Eyewitness identification under stress in the London Dungeon"
(Note: You may study this OR Ruva et al. Check which one your teacher has selected!)
The Aim: To see if high levels of anxiety and stress reduce the accuracy of eye-witness identification.
The Method: 56 participants visited the Horror Labyrinth at the London Dungeon. An actor (the "Scary Person") stepped out and blocked their path. The researchers used heart rate monitors to divide people into "Low Anxiety" and "High Anxiety" groups based on their physical reaction to the scare. Later, they had to identify the actor from a line-up.
The Results:
- High Anxiety participants were much less accurate at identifying the actor (only \(17\%\) correct).
- Low Anxiety participants were much more accurate (\(75\%\) correct).
- Females reported higher levels of anxiety than males.
The Conclusion: High stress impairs our ability to encode (take in) information about a person’s face. This challenges the idea that "dramatic" memories are always clearer.
Key Takeaway: If a witness is terrified during a crime, their identification of the suspect in a line-up is statistically less reliable.
4. Choice Study B: Ruva, McEvoy and Bryant (2007)
"Effects of pre-trial publicity and jury deliberation on jury bias"
The Aim: To see how Pre-Trial Publicity (PTP)—the news stories people see before a trial starts—affects a jury’s verdict and their memory of the evidence.
The Method: Participants (acting as a "mock jury") were exposed to either negative news stories about a defendant or neutral stories. They then watched a trial and discussed it as a group (deliberation).
The Results:
- Participants who read negative news were more likely to vote "Guilty."
- They also suffered from source memory errors. This means they mistakenly thought they heard incriminating "facts" during the trial, when they actually just read them in the news stories beforehand.
The Conclusion: It is very hard for jurors to "ignore" what they have seen in the media. The news biases their perception of the actual evidence presented in court.
Key Takeaway: Jurors are not blank slates; the media can "contaminate" their memory of a trial before it even begins.
Quick Review: Comparing the Studies
Loftus & Palmer: Laboratory experiment. Focuses on leading questions. Uses students. Shows memory is fragile.
Bradbury & Williams: Field study (secondary data). Focuses on race and juries. Uses real cases. Shows the system is biased.
Valentine & Mesout: Natural experiment. Focuses on stress/anxiety. Uses tourists. Shows high stress blocks memory.
Ruva et al: Mock jury experiment. Focuses on the media (PTP). Shows that news stories confuse our memory of facts.
Common Mistake to Avoid:
Don't confuse Experiment 1 and Experiment 2 of Loftus and Palmer!
- Exp 1 is about speed estimates (The Verbs).
- Exp 2 is about the "memory" of something that wasn't there (The Broken Glass).
Evaluation Tip:
When evaluating these studies, always think about Generalisability. Loftus and Palmer used students—do students represent the whole population? Bradbury and Williams used US trials—does this apply to the UK or other legal systems? This is a great way to pick up marks in your 8-mark questions!