Questions & explanations
1. A profiler notices that a burglar always steals only electronic items and never leaves fingerprints. How would an investigative psychologist use this to create a profile?
The psychologist would see that the burglar has a strong interest in electronics, which might mean they know how to sell them quickly. The care not to leave fingerprints shows they are cautious and maybe have been caught before. The psychologist would infer the offender is likely young, probably male, and may have a past for theft. They might also guess the offender has a place to store the goods or a connection to a fence. Using research on burglars, the psychologist could add that such specific targeting often means the offender has a personal need for money. The profile would suggest police look for someone with a recent job loss or a habit of visiting pawn shops. This profile guides where police search and what questions to ask.
2. How does profiling a terrorist bomber differ from profiling a serial bomber for personal reasons?
Terrorist bombers act for a political or religious cause, so their targets have symbolic meaning. They often work in groups and plan attacks to get media attention. Personal bombers, like a disgruntled employee, target specific people or places that relate to their anger. Terrorist bombers may claim responsibility and want to spread fear. Personal bombers usually don't announce their crimes and may try to hide. The profiler for terrorism looks at the group's ideology and communication style. For personal bombers, the focus is on the bomber's personal history of conflict. Both profiles help police decide if more suspects are involved and what the next target might be.
3. How would you explain the difference between the probability of a behavior given a profile and the probability of a profile given a behavior?
The probability of a behavior given a profile (like 'the offender leaves a signature' given that he is a thrill-seeker) is a likelihood. It tells how common that behavior is among that type. The probability of a profile given a behavior (like 'the offender is a thrill-seeker' given that he left a signature) is what we want to know. These two are often confused. A common mistake is to assume they are the same. For example, if 90% of thrill-seekers leave signatures, but only 1% of all offenders are thrill-seekers, then even if you see a signature, the chance the offender is a thrill-seeker might still be low. Bayes' rule helps get the correct second probability.
4. Compare geographic profiling with the method of 'least effort' in offender travel. Give an example of when they might agree or disagree.
Geographic profiling uses math, and the least-effort idea says offenders pick the easiest travel route. They often agree because most offenders choose short, simple trips to familiar areas. For example, an offender who works in one part of town might leave crimes there. But they can disagree if the offender has a strong reason to travel farther, like targeting a specific victim type only found in a rich area. The least-effort model would predict crimes near home, but geographic profiling might find a different pattern. Profilers must combine both ideas and look at the actual crime locations. They adjust their algorithm based on what the data shows.
5. In a case where a person claims to have recovered a memory of abuse during therapy, how should a court decide if the memory is reliable?
The court should consider whether the therapy used leading questions or techniques known to create false memories. It should check if there is any independent evidence, such as medical records or testimony from other witnesses. The court may ask expert witnesses to explain the scientific consensus on memory and suggestibility. It should also examine the circumstances of the recovery: if it occurred spontaneously, it may be more reliable than if it came from hypnosis or guided imagery. Ultimately, the judge may decide to allow the memory but instruct the jury to be cautious. Many courts now set strict rules for admitting recovered memories.
6. How does the story model differ from the mathematical model of jury decision-making?
The mathematical model, like Bayesian reasoning, says jurors weigh evidence by assigning probabilities and updating them as new evidence comes in. In contrast, the story model says jurors build a narrative and decide based on the best story. The mathematical model treats decision-making as a step-by-step update of probabilities, while the story model sees it as creating a coherent whole. Research shows that jurors often use stories, not math, because stories are easier for people to understand. The story model better predicts actual verdicts in many studies. Both models have value, but the story model matches how people naturally think.
7. A series of thefts from churches involves only gold items. How would a profiler approach this case?
The profiler would first note the specific target: gold and churches. This suggests the offender wants valuable metal and may have a way to melt or sell it. The choice of churches might mean the offender is familiar with their schedules and knows when they are empty. The profiler would consider if the offender has a grudge against religion or just sees churches as easy targets. From research, many such thieves are local and may have a criminal record for theft. The profile might point to a young adult with drug problems, needing quick cash. Police would look for someone with prior incidents involving religious buildings or gold buying.
8. Explain how a geographic profiler's algorithm might change if the offender uses public transit instead of a car.
If the offender uses public transit, the algorithm must consider transit routes and stops. Crimes may cluster near train stations or bus lines, because the offender can only travel where transit goes. The typical 'distance decay' curve might be longer along transit lines, since trains cover distance fast. The profiler would also think about walkability from stops to crime sites. The algorithm can add a network of transit paths instead of straight-line distances. This makes the probability map look like a spiderweb along routes, not a simple circle. The home location is likely near a transit stop that connects to all crime locations.
9. Explain how inference methods in investigative psychology allow profilers to guess an offender's background from crime scene behavior.
Inference methods work by comparing crime scene details to what is known from research. For instance, research shows that offenders who use a lot of force are often younger and less experienced. If a crime scene is very neat, it might mean the offender planned carefully and has some education. Profilers look at things like the type of weapon, words spoken, or how the victim was treated. From these clues, they infer traits like age, job, or even whether the offender knows the victim. This is not perfect, but it gives police a direction to investigate. The inference is always based on statistical patterns from past solved crimes.
10. Why do profilers pay close attention to the type of injuries in sexual offenses?
The type of injury can tell whether the offender is angry, wants control, or is trying to hurt the victim in a specific way. For example, overkill with many wounds often means deep anger against the victim. Minimal injury might mean the offender just wanted to force the victim to submit. Profilers also look at where on the body injuries are—like focusing on the face shows personal rage. This helps guess the offender's relationship to the victim or their mental state. Combining injury patterns with other crime scene details builds a fuller profile. It guides police on whether the offender likely knew the victim or is a stranger.
11. What is 'thematic consistency' in criminal profiling?
Thematic consistency means that an offender's behavior across different crimes often follows a repeated pattern or story. This pattern reflects how the offender sees himself and his role in the crime. For example, some offenders always play the role of a 'hunter' who controls the victim, while others see themselves as 'victims' and blame others. Profilers look for these consistent themes to link crimes to the same person. The theme can include the way the offender talks to the victim or the things he takes from the scene. Recognizing this consistency helps build a more accurate profile of the offender's personality and motives.
12. Give an example of how a profile could use thematic consistency to link two crimes that seem different on the surface.
Imagine one crime where the offender broke into a house and stole jewelry but did not harm the sleeping residents. Another crime involved a car theft where a note was left apologizing to the owner. On the surface, these seem unrelated. But a profiler notices both crimes show the offender avoiding confrontation and feeling guilt. The note and the careful entry show a consistent theme: the offender sees himself as a 'non-violent thief' who wants to avoid hurting anyone. This thematic similarity suggests the same person committed both crimes. The profile then focuses on someone who is remorseful and avoids direct victim contact.