Welcome to Criminal Psychology!
In this chapter, we are going to dive into the world of crime. But instead of just looking at "what" happened, we are going to ask the much more interesting question: Why? We will explore why people turn to crime, how the police build cases without being biased, what happens inside a courtroom, and how we handle people after they’ve been convicted.
Don't worry if this seems like a lot of information at first! We’ve broken everything down into four clear topics. Think of this as a journey through the criminal justice system, from the first spark of a criminal thought to the prison cell.
1. Turning to Crime
Why do some people break the law while others don't? Psychologists look at three different "lenses" to explain this: biology, society, and our thought processes.
The Three Explanations
1. Biological: The ‘MAOA gene’
Some psychologists believe crime is in our DNA. The MAOA gene is often called the "warrior gene." It’s responsible for breaking down brain chemicals like dopamine and serotonin. If this gene isn't working properly, a person might become more aggressive or impulsive. Analogy: Imagine a car with a sensitive accelerator and no brakes; that’s how a brain with an abnormal MAOA gene might feel.
2. Social: Differential Association
This theory suggests we learn to be criminals from the people around us. If you grow up in a group where crime is seen as "normal" or even "cool," you are likely to pick up those same attitudes. You learn the techniques (how to do it) and the motivations (why it’s okay to do it).
3. Cognitive: Rational Choice Theory
This view treats criminals like businessmen. It suggests that people choose to commit a crime after weighing the costs (getting caught/going to jail) against the benefits (money/status). If the benefit is high and the risk is low, they go for it.
Key Study: Raine et al. (1997)
Aim: To see if murderers who pleaded "Not Guilty by Reason of Insanity" (NGRI) had different brain activity than non-murderers.
Method: Used PET scans (which show brain activity) on 41 murderers and 41 "normal" controls.
Results: The murderers had much lower activity in the prefrontal cortex (the part of the brain that controls impulses and "brakes" our behavior) and the amygdala (which processes emotion).
Conclusion: Brain abnormalities might make it harder for some people to control their violent urges.
Practical Application: How do we stop it?
Zero-Tolerance Policing: Based on the "Broken Windows" theory. If police fix small problems (like graffiti or broken windows) immediately, it prevents bigger crimes from happening because it shows that someone is watching and cares.
Anger Management: If crime is caused by a lack of impulse control, we can teach people Cognitive Behavioral Therapy (CBT) techniques to recognize their triggers and "cool down" before they act.
Quick Review: Turning to crime is explained by Nature (genes/brain) and Nurture (who we hang out with and how we think).
2. Building a Case
Once a crime is committed, the police have to find the culprit. But can we always trust forensic evidence like fingerprints?
The Problem: Bias in the Lab
Emotional Context: If a fingerprint expert is told a crime was particularly gruesome or violent, they might feel extra pressure to find a match. This is called expectancy bias—they expect to find a match, so their brain "sees" one even if it’s not perfect.
Cognitive Biases: These are mental shortcuts. For example, if an expert is told that the suspect has already confessed, they are much more likely to "see" a match in the evidence to support what they already believe.
Key Study: Hall and Player (2008)
Aim: To see if the "emotional context" of a crime (e.g., a report of a gruesome murder) would influence fingerprint experts.
Method: 70 fingerprint experts were given a "blurred" fingerprint. Half were told it was from a low-stress crime (a forged £50 note), and half were told it was from a high-stress crime (a murder).
Results: Although the experts in the high-stress group felt more affected by the story, it didn't actually change their final decision! They remained professional.
Conclusion: Experts are good at staying objective, but the fear of bias is still something we need to manage.
Practical Application: Reducing Bias
ACE-V: This is a step-by-step process for fingerprinting: Analyze, Comparison, Evaluation, and Verification. The "Verification" part is key—a second expert checks the work without knowing the first expert's result.
Linear Sequential Unmasking (LSU): This means giving experts information in small chunks. They analyze the evidence before they are told anything about the suspect. This stops them from being biased by the story.
Did you know? Even "objective" science like DNA or fingerprinting can be subjective because a human still has to interpret the results!
3. In the Courtroom
The case is built, and now we are in court. Does the jury only look at the facts? Sadly, no. They are human, and they can be persuaded by things that shouldn't matter.
What Persuades a Jury?
1. Characteristics of Witnesses/Defendants: Juries tend to be more lenient toward "attractive" defendants. They also trust witnesses who appear confident more than those who seem nervous, even if the nervous witness is telling the truth!
2. Inadmissible Evidence: Sometimes a lawyer says something they shouldn't, and the judge tells the jury to "ignore that." Memory Aid: Try not to think of a white bear. Hard, right? Once a jury hears something, they can't truly "un-hear" it.
3. Pre-trial Publicity: If a case has been all over the news, the jury might already have an opinion before the trial even starts.
Key Study: Dixon et al. (2002)
Aim: To see if a defendant's accent influenced whether a jury thought they were guilty.
Method: Participants listened to a recording of a suspect being interviewed. The suspect had either a "Brummie" (Birmingham) accent or a "Standard" (posh) accent.
Results: The suspect with the Brummie accent was rated as significantly more guilty. This was even worse if the suspect was Black or accused of a "blue-collar" crime like armed robbery.
Conclusion: Stereotypes about accents and race can lead to unfair trials.
Practical Application: Leveling the Playing Field
Expert Witnesses: We can bring in psychologists to explain to the jury why an eyewitness might be wrong or how bias works. This helps the jury focus on the facts.
Story Order: Lawyers are encouraged to present evidence in chronological order (as a story). Juries find it much easier to believe a story that flows from start to finish rather than a "witness order" where facts are jumping around.
Quick Takeaway: The courtroom is as much about psychology and persuasion as it is about the law.
4. Managing Offenders
What happens after the "Guilty" verdict? How do we stop them from doing it again (recidivism)?
Responses to Crime
1. Imprisonment: Taking away freedom. This is meant to be a deterrent (scaring people off crime) and incapacitation (keeping them away from the public).
2. Non-custodial punishment: Things like community service or fines. This is often better for minor crimes as it keeps the person in their job and with their family.
3. Rehabilitation: Fixing the underlying problem. This could be drug treatment, education, or therapy.
Key Study: Haney, Banks, and Zimbardo (1973)
Note: You might know this as the "Stanford Prison Experiment."
Aim: To see if the brutality in prisons was due to the personalities of the people or the situation (the roles they play).
Method: 24 healthy male students were randomly assigned to be "guards" or "prisoners" in a fake basement prison.
Results: The guards became cruel and aggressive; the prisoners became passive and depressed. The study had to be stopped after just 6 days (instead of 14) because it became too dangerous.
Conclusion: The situation and the roles we are given have a massive impact on how we behave, regardless of who we are "on the inside."
Practical Application: Reducing Reoffending
Restorative Justice: The offender meets the victim. This makes the crime "real" to the offender and allows them to take responsibility. It has a high success rate in reducing reoffending.
Employment/Education: Research shows that if an ex-offender has a job and a steady income, they are much less likely to turn back to crime. Programs that help them get degrees or learn trades are vital for the economy.
Common Mistake to Avoid: Don't just say "prison doesn't work." Instead, use the psychological evidence to explain why (e.g., the "situational" factors found by Zimbardo) and suggest alternatives like restorative justice.
Final Summary
Criminal psychology shows us that crime is a complex mix of biology, environment, and thinking patterns. By understanding these, we can improve how police find evidence, how juries make decisions, and how we help offenders change their lives for the better. Good luck with your studies—you’ve got this!