Psychology as a Science

Research Methods

The Need for Psychological Science

• Common Sense?• “Hindsight is 20:20”

– Hindsight Bias

• Question everything!– Critical Thinking:

The Scientific Method

• Definition: Approach used by psychologists to systematically acquire knowledge and understanding about behavior and other phenomena

• Steps: 1. Identify Problem or Question2. Formulate a Hypothesis3. Collect Data4. Analyze Data5. Draw Conclusions

Theories v. HypothesesTheory• Definition: broad explanations

and predictions concerning phenomena of interest– Based on observation and

predicts future behaviors/events

• Example:Attachment Theory in adult

relationships:

--Four attachment styles have been identified in adults: secure, anxious-preoccupied, dismissive-avoidant, and fearful-avoidant.

Hypothesis• Definition: a prediction,

stemming from a theory, stated as a testable question

• Example:“People with high self-

esteem are more likely to express a secure attachment style in relationships than those with low self-esteem.”

PSEUDOSCIENCE

• Pseudoscience – diverges from the required standards for work or is

unsupported by sufficient scientific research

• Examples:– Phrenology (bumps on head)– Astrology– Telepathy– UFOs

Research Terms• Study: broad term used to describe a

specific group of research (includes prior research, hypotheses, participants, etc.)

• Participants: people chosen to partake in a study (representative sample) a.k.a. subjects– Population: a whole group of people based on a

common characteristic– Sample: a small representation of a particular

population

• Random Sample: fairly represents a population; every member of a population has an equal chance to partake in the study

Research Terms cont’d

• Variables: Behaviors, events, or other characteristics that can change in some way.

Research Methods• Archival Research: use existing data to

test a hypothesis (e.g.: newspapers, census documents, college records).

• Naturalistic Observation: investigator observes a naturally occurring behavior and does not make a change in the situation

• Survey Research: using a sample of a population, people are asked a series of questions about their behavior, thoughts, or attitudes.

• Case Study: an in-depth, intensive investigation of an individual or small group of people

• Correlational Research: shows the relationship between two sets of variables to determine if they are associated or “correlated”

• Example: Violent TV and Viewer Aggression

– Positive Correlation: as 1 variable increases, the other variable increases

– Negative Correlation: as 1 variable increases, the other variable decreases

• Correlation does NOT EQUAL Causation!!!

Violent TV and Aggression

Positive Correlation

0102030405060708090100

<1 hr 1-3 hrs 3+ hrs

Hours of Violent TV

Le

ve

l o

f A

gre

ss

ion

What does this mean??

Hours of exercise & WeightNegative Correlation

100120140160180200220240

< 3 hrs 3-5 hrs 5+ hrs

Hours of excercise per week

Poun

ds

What does this mean??

Correlation ≠ Causation!

• Illusory correlation: perception of a relationship where none exists– 3rd variable that has an influence

•a.k.a. extraneous variable

– Length of Marriage & Hair Loss• 3rd variable: age

Experimental Research• Investigation of the relationship

between two or more variables by deliberately producing a change in one variable in a situation and observing the effects of that change on other aspects of the situation

• The ONLY way to demonstrate causation!

Key Terms in Experimental Research

• Manipulation: the change that the experimenter deliberately produces in a situation

• Experimental Group: The group receiving the manipulation

• Control Group: The group that receives no manipulation, i.e. “stay normal”

• Independent Variable: variable that is manipulated (effect is studied)

• Dependent Variable: variable that is measured and is expected to change due to the manipulation (i.e. the IV changes the DV)

• Random Assignment: participants are assigned to different experimental groups based on chance

• Significant Outcome: meaningful results make it possible to support hypothesis

• Replication: repetition of research, sometimes changing procedures, settings, or participants in order to strengthen confidence in previous findings

• Double-Blind Procedure: an experimental procedure in which both the experimenter (s) and participants do not know which group was the control and which was treated

Ethics• APA Guidelines

– Protection of participants from physical and mental harm

– Rights of participants to privacy regarding their behavior

– Assurance that participation in research is completely voluntary

– Necessity of informing participants about the nature of the procedures prior to their participation in the experiment

• Informed Consent: document signed by participants affirming that they know the basic outline of the research study and are aware of what their participation involves.

• Debriefing: a conversation or document reviewed by the participant with the researcher explaining details about the research, answering any questions, and explaining any manipulation

Stanley Milgram• 1960’s obedience study• Participants were told to give increasingly

stronger electrical shocks to another person as they answered each question incorrectly. The highest level of shock could kill the person– Reality: no actual shock was delivered but the

confederate was an actor who pretended to be shocked.

• 65% of the participants delivered the highest level of electrical shock when told to do so

• Why is this so important? Was this unethical?– Extremely trying set of circumstances that could

have harmed the participants emotional/physical state

Threats to Experiments

• Experimental Bias: factors that distort how the independent variable affects the dependent variable in an experiment– E.g. Gender, Culture, Experimenter bias

• Placebo: a false treatment, such as a pill, having no significant effect on participant

Describing Data

• Mode: most frequently occurring score• Mean: arithmetic average of a

distribution• Median: the middle score in a

distribution (half of the scores are above, half are below)

• Outlier: scores that are so high or so low that don’t fit into the central tendency– *Can skew data results

FAQ’s about Psych. Research

• Can Lab experiments transfer to everyday life?

• Does behavior depend on one’s culture?– Culture: enduring behaviors, ideas, attitudes,

and traditions shared by a large group of people and transmitted from one generation to the next.

• Does behavior vary with gender?– More similar than we are different yet we focus

on differences• Why study animals? Is it ethical?

– Similar processes of learning, feeling, and exhibiting emotion

– Naturalistic Observation over experimental to protect the animals

?