PSYCHOLOGY AND LAW
Human behavior lies at the heart of psychology and the law.
Psychology is the scientific study of behavior and mental processes in an attempt to understand,
predict, and in some cases control human behavior
What is Psychology?
Psychology is the scientific study of behavior.
anything an animal or human does, feels, or thinks.
Psychology is a science firmly based in empirical research.
Psychology has broad application.
The legal system is comprised of a body of laws, rules, regulations, and procedures.
The legal system is designed to govern, regulate and control human behavior
(Ogloff & Finkelman, 1999).
Psychology and The Law
Concerns issues arising out of the relationship between human behavior and the law, legal
system, and legal process(Weiner, 1997)
Psychologists working in law and psychology study empirically the assumptions about human
behavior that underlie the operation and functioning of the law.
Social scientists assess the reasonableness and validity of the evidence
Differences between Law and Psychology (law vs. psychology)
1) Stare decisis vs. Creativity
o Stare decisis legal precedent (Doing what was doing before)
If someone committed murder and you gave them 10 years, the next person who
had a similar case should also get 10 years
Want to keep things consistent so its fair
o Creativity like stare decisis, it is based on previous decisions but there is always some
new twist (something innovative)
2) Hierarchical vs. Empirical
o Hierarchical all lower courts are bound by higher courts (but not the other way
o Empirical consistent and supporting data to support the validity and reliability of
findings -> theories (can be proven wrong)
3) Adversarial vs. Experimental
o Adversarial to find the truth, you have two conflicting points of view, they are battled
out in court, the one that argues it out the best is now considered the real truth
o Experimental experiments to find an objective truth (get rid of biases, distortions of
4) Prescriptive and Descriptive
o Prescriptive tells you what to do
o Descriptive describes why you did what you did
1 PSY328 LEC1
5) Idiographic vs. Nomothetic
o Idiographic case by case basis decided by specific facts
Even though you have to use stare decisis, each case may be a bit different
o Nomothetic general principles, averages (what will the average person do in this
situation? Not everyone may do it, but the majority)
6) Certainty vs. Probablistic
o Certainty in the results -> if you go to court, you will be found guilty or not guilty (yes
or no -> all or none)
o Probabilistic probability that there is 80% likelihood they are guilty (on a scale of 0-
7) Reactive vs. Proactive
o Reactive based on reactions happened to an event
o Proactive look at anything you want (what happens if this happened..)
8) Operational vs. Academic
o Operational applied, used for real world problems
o Academic it can be operational, but it can be just academic (quest for knowledge)
Psychology IN the law
o Use of psychology IN law -> questionnaire, bias scale, fitness trial test
o May not be psychologists doing the test, but they may make the test
o Ex: Modern Racism Scale
Psychology AND the law
o Critical evaluation of some aspect of law by psychology (validate techniques already
used and new techniques)
o Ex: Best way to do a line-up
o Ex: manipulate race of defendant and how salient how not being prejudice is
Research to see what the best way is to screen for bias
Psychology OF the law
o Study of law itself previous things (why and when people will obey the law)
o Ex: how does Canada and US screen for bias? Which is better?
The Law in Canada
Canada is a common law country
o What does that mean?
Lets look at some history, plus the differences between Common and Civil law
Common vs. Civil
o Stare decisis
Most British countries, North American (created in England)
Based on stare decisis or precedence what happens before has to be what happens later
Basically law is created by cases, ultimately by judges who decide these cases
o If you had a pure common law, wouldnt have laws written down, it would have previous
court cases (big court summary)
o Judge has passive role
o Canada: Decisions made by judges, then later judges look at the previous decision and
decides what to do in the future from there
Adversarial system of litigation
o When you imagine on TV, two lawyers fighting it out
Most European countries (most predominant law of the world)
o Second most predominant is religious based law and then common law
Based on statutes
Inquisitorial system of litigation