Psychology and the Law

Research Methods

Plan for Today

• Research methods

• Class experiment

Levels of Explanation

• Poem written on a piece of paper

a) Ink marks on paper

b) Chemical constituents of paper and ink

c) A collection of letters in English language

d) A collection of words in English language

e) A work of art and meaning

Research Methodology

1. General biases- self serving bias- I knew it all along phenomena

2. Biases in assessing covariation- illusory correlation

3. Biases in inferring causation- the fundamental attributional error- The illusion of control

Correlational vs. Experimental Research

• Smoking is correlated with lung cancer

• High grades are correlated with successful careers

• Eating Frosted Flakes is correlated with lower cancer rates

• In Taiwan birth control use is correlated with number of household appliances

Correlational Research

• Establishes whether there is a relationship between two or more variables

• CANNOT INFER CAUSALITY

1. Directionality problem

2. Potential for a third variable (confound)

Experimental Research

• Considered the most powerful tool for determining causal relationships

• Random Assignment: ensures that every participant has an equal chance of being assigned to any of the conditions

• This minimizes the chance that a pre-existing difference between groups is the cause of the “experimental effect”

Trial and Error

• Try something, if it works try it again, if not discard

• If it works again, try it again.• If it works often, use it often.• Problems:• Harder to understand the mechanisms

behind why something works.• Ignores research in related areas.

Example word generation task

O F R E

C M P A

K L I N

E T P S

Word Generation Task

A B T I

C K S A

H R O M

E T P L

Research Demonstration

• Purpose of study?

– the effects of anxiety on performance

• Eperimental hypothesis?

- anxiety will decrease performance, those in anxiety condition will generate less words than those in the control condition

Research Demonstration

• Independent variable?- made to feel anxious or not• Dependent variable?- number of words generated • Manipulation check?- people in anxiety condition will score

higher on questionnaire than control condition

Research Demonstration

• Random assignment

• Random sample

• Internal validity

• External (ecological) validity

• Reliablility

Legal Quiz

• If I were charged with negligent manslaughter in Toronto:

• What type of offense would it be?

• What court would I be remanded to?

• Where would I appeal my conviction?

Legal quiz

• Who writes the laws of the land?

• What are the Division of Powers?

• What are the two dimensions of evidence?

• When can an opinion be offered by a witness in court?