introduction to forensic psychology

alfred binet (1900)

looked at suggestibility

if an individual is told to study objects or remember something and then asked leading questions that may be inaccurate, or even questions that are more direct, this can change the memory of the individual who are asked to answer

free recall is way more accurate than asking questions about it, even if the questions are direct.

forensic psychology

a field of psychology that deals with all aspects f human behaviour as it relates to the law or legal system

narrow definition of forensic psychology

clinical psychology as it pertains to the legal system

assessing reating, consulting, with those who have commited a crime

broad definition of forensic psychology

research endeavor that examines human behaviour directly related to legal processes and cliinical work within the legal system

clinical forensic psychologists

broadly concerned with the assessment and treatment of mental health issues as they pertain to the law or legal system

does an offender pose a risk to the community?
who is best suited for a job in policing?

• interviews with candidates of police jobs - f they have history with aggression, maybe the job isn’t what is best for them, or if they show a lot of patience and are good in stressful situations, they might be good for the job

is the law enforcement officer ready to go back to work after a stressful event

experimental forensic psychologists

may never interact with legal system, lawyers, criminals

be in an office doing cognitive experiments/social experiments

interested in human behaviour, cognition, emotion

asks: what factors influence jury decision making, how can we effectively exist among law enforcement officer

legal scholar: someone who conducts research and has a law degree

psychology and the law

using psychology to study the operation of the legal system

testing assumptions: eg. are eyewitnesses accurate, are the practices currently carried out in the legal system effective and/or are they valid, are juries fair/do they have biases that impact decisions, do the way that lawyers interact with juries relay information in a practical way

psychology in the law

using psychology within legal system as it currently operates

eg. providing expert testimony in court

• psychologist or not (lawyer, judge) applying knowledge

hostage situations - nature of human communication

psychology of the law

the use of psychology to study the law itself

eg. does a law reduce the occurrence of a crime, when does eyewitness testimony no longer good, is the subject reliable to give an eyewitness testimony, how do we explain legal rights to a child offender,

if in therapy and client has intentions of harming someone, legal system in place for mental health provider to report this

witness vs expert witness

witness: can testify about what they directly observed

• fact witness - observed the crime or they can provide context/information about the person who committed the crime, or a victim. needs to be something that they directly observed

expert witness: can provide court with their personal opinion on matters relevant to the case

• doesn’t need to observe the crime

• testimony needs to be deemed reliable and helpful

• needs to be trained in legal proceedings, years of experience, trained in clinical psychology

• not meant to be an advocate for the either the victim or defendant - is objective and provides information

• sometimes defendant/witness will hire an expert witness that will benefit their side, but the witness needs to be objective in terms of their view

• acts as an educator to the judge and/or jury

challenges in being an expert witness

experts need to know:

• details of the case and their own testimony (and provide evidence for that testimony)

• their role in the proceedings (what they can and cant say)

• how to communicate in persuasive and helpful manner

can be challenging because of differences between psychology and law

differences between psych and law

epistemology, goals, knowledge, methods, criterion, principles , court behaviour

differences between psych and law: epistemology

law → truth is subjective

• doesn’t matter what happened within a court system, it matters who is able to argue their points better and who is better at providing their evidence

psych → we can uncover hidden objective truths

• what does the data support

differences between psych and law: goals

law → tells people how to behave, provides punishments

psych → describe how and why people behave the way they do

• falls under people abiding by the law - wants to see why you behave either way

differences between psych and law: knowledge

law → idiographic analysis, rational application of logic

• case by case basis

• common sense

psych → based on empirical, group based data

• focus on the group, not individual people

• more people in the sample, the more accurate it is

differences between psych and law: methods

law → constructing compelling narratives that are consistent with the law

• “the defendant did something and it technically falls under the rules of the law”

psych → empirical, want to replicate results

• data collection, analysis, interpretation, replicate (to be sure the hypothesis is supported as much as it can)

overall: psych controls confounding variables, law does not

differences between psych and law: criterion

law → guilt is determined using several criteria, beyond a reasonable doubt

• not just quantitative criteria

• “beyond a reasonable doubt”: when a judge/jury make a decision, they have no reason to believe the opposite of what their verdict

psych → cautious to accept something is true

• always thinking about the limitations of the study can be improved

• statistics are very conservative - if something happens half the time, 80% of the time, we do not accept that as the truth

  • p value of 0.05, suggests that these things must be happening 95% or more in order to be true

differences between psych and law: principles

law → tries to make one explanation the best reason for the events

psych → exploratory approach, considers multiple explanations

differences between psych and law: court behaviour

law → fewer restrictions on lawyers

• lawyers can present a wide range of evidence, as long as its admissible

• can call on as many witnesses as they want, and can present the case as they see fit

psych → only one role in court, if any

• psychologist only has one role in court - expert witness, and are only used if relevant

general acceptance test

helps to determine if an expert testimony can be accepted

an expert testimony will be admissible in court if the basis of the testimony is generally accepted within the relevant scientific community

ex. criminal profiling can not to used to determine guilt, as it is not seen as accurate in the scientific community

two major criticisms:

• vagueness of the term :general acceptance”

  • at what point is something generally accepted? do we need half of the community to agree? 90%?

• whether trial judges can make this determination

  • judges aren’t scientists and cant be ale to make this distinction

daubert v merrell dow pharmaceutical trial

bendectin

• drug used for nausea and vomiting in pregnant women

  • prosecution’s expert witness was not permissible in court, as the testimony was not seen as commonly agreed on knowledge

US supreme court laid out 4 specific criteria for expert testimony, now called the daubert criteria:

1. research has been peer reviewed

2. research is testable

3. research has recognized rate of error

   • is the research accurate and is it reliable? what is the p value?

4. research adheres to professional standards

   • peer ethics, meet the gold standard of methods, statistical analysis, interpretation

mohan criteria

used in canada, similar to daubert

1. must be relevant to case

   • states that a fact is more or less likely

   • ex. “men are more likely to engage in crimes”, instead say “ it is more likely that a person is involved in interracial violence than intraracial crimes”

2. must be necessary to assist the trier of fact

   • must go beyond common understanding of court

   • needs to teach jury something they don’t already know

3. must not violate any rules of exclusion

   • providing testimony about someone’s past crimes could be causing juries to make assumptions

   • can’t be prejudicial towards defendant

4. must be a qualified expert

In addition: experts must be independent and impartial, with no conflict of interest especially with financial gain