Source: Barron’s AP Psychology

Research Methods

Hindsight Bias

• People have the tendency upon hearing about research findings (and many other things) to think that they knew it all along.

Applied Research

• Research conducted to solve practical problems

  • Example: Comparing two different study methods and their effects on grades

Basic Research

• Explores questions that are of interest to psychologists but are not intended to have immediate, real-world applications

  • Example: Studying how people form their attitudes about others and how different cultures define intelligence

Hypothesis

• States your predictions about what your research will find

The dependent variable depends on the independent variable. You can manipulate the independent variable to produce different results for the dependent variable.

EXAMPLE:

Hypothesis - watching violent television programs makes people more aggressive.

Independent variable - watching television violence

Dependent variable - the person’s aggression and behaviour

Theory

• Systems of ideas that can explain certain aspects of human thoughts, behaviors and emotions

Operational Definition

• A description of something in terms of the operations (procedures, actions, or processes) by which it could be observed and measured

EXAMPLE:

What programs will be considered violent? What behaviours will be considered as aggressive?

Validity

• Measures what the researcher set out to measure; it is accurate

Reliability

• When it can be replicated; it is consistent

Participants (Subjects)

• The individuals on which the research will be conducted

Sampling

• The process by which participants are selected

Population

• Anyone or anything that could possibly be selected to be in the sample

When selecting a sample, you want it to be representative of a larger population

Random Selection

• Every member of the population has an equal chance of being selected

• Increases likelihood that sample will represent larger population

Stratified Sampling

• A process that allows a researcher to ensure that the sample represents the population on some criteria

EXAMPLE: if the population is 300 African Americans, 200 Latinos, and 50 Caucasians, I would pick 60 African Americans, 40 Latinos, and 10 Caucasians.

Experimental Method

Laboratory Experiments

• Conducted in a lab, a highly controlled environment

• Main advantage is you can modify the extent to which they are controlled

Field Experiments

• Conducted out in the world

• More realistic

Preferred method of research is experiment

• Only through a carefully controlled experiment can one show a causal relationship

• Avoids as many confounding variables as possible

Confounding Variables

• Any difference between the experimental and control conditions, except for the independent variable, that might affect the dependent variable.

Assignment

• Process by which participants are put into a group (experimental or control)

Random Assignment

• Participant has an equal chance of being placed into any group (limits participant-relevant confounding variables)

• Differs from random sampling as random sampling is when you’re choosing participants from the population but random assignment is when you’re splitting the participants into groups.

Group Matching

• Researchers attempt to categorize the subjects (by age, health status, gender, etc.) and ensure that the control group has members similar to those in the experimental group

Situation-Relevant Confounding Variables

• The situations into which the different groups are put must be equivalent except for the differences produced by the independent variable in order to avoid this

• Examples: time of day, the weather, and the presence of other people in the room.

Experimenter Bias

• The unconscious tendency for researchers to treat members of the experimental and control groups differently to increase the chance of confirming their hypothesis

Double-Blind Procedure

• Neither the participants nor the researcher are able to affect the outcome.

• Eliminates experimenter bias

• Most common way is for the researcher to have someone blind to the participants’ condition interact with the participants.

Single Blind Procedure

• Only the participants do not know to which group they have been assigned.

• Minimizes effect of demand characteristics and response or participant bias

Demand Characteristics

• Participants use the cues about the purpose of the study to respond appropriately

Social Desirability

• Tendency to try to give answers that reflect well upon yourself.

Hawthorne Effect

• A type of reactivity in which individuals modify an aspect of their behaviour in response to their awareness of being observed

Placebo Method

• Whenever participants in the experimental group are supposed to ingest a drug, participants in the control group are given an inert but otherwise identical substance

• Allows the separation of physiological effects of the drug and psychological effects of people thinking they took the drug (placebo effect)

Counterbalancing

• Using participants as their own control group

• Using the entire group at once to do the experiment and control may lead to order effects

  • This can be eliminated by making half the participants do the experiment task first and half the participants do the control task first and then switching.

Correlational Method

Correlation

• Expresses a relationship between two variables without ascribing cause

• CORRELATION ≠ CAUSATION

• Positive Correlation

  • Presence of one thing predicts the PRESENCE of the other

• Negative Correlation

  • Presence of one thing predicts the ABSENCE of the other

• Ex Post Facto Study

  • Quasi-experimental study examining how an independent variable, present prior to the study, affects a dependent variable

Survey Method

• The researcher does not manipulate any variable → only looking for a correlation

• No control for participant-confounded variables

• Usually low response rate

Naturalistic Observation

Observing participants in their natural habitats without interacting with them at all (unobtrusive)

• Control is sacrificed to get a realistic and rich picture of the participant’s behaviour

Case Studies

• Get a full, detailed picture of one participant or a small group of participants

• While case studies allow researchers to get the richest possible picture of what they are studying, the focus on a single individual or small group means that the findings cannot be generalized to a larger population.

Statistics

Descriptive Statistics

Frequency Distribution

• A tabular representation of the number of times a specific value or datum point occurs

• Can be turned into frequency polygons (line graphs) or histograms (bar graphs)

Measures of Central Tendency

• Mean (average), Median (middle), Mode (most frequent)

• Can be distorted by extreme scores or outliers

  • When this occurs, the median is often used as a better measure of central tendency

Skewed distributions are caused by outliers and the distribution curve is not symmetrical

Positively Skewed

• Includes a high extreme score

• More low than high scores

• Mean is higher than median

Negatively Skewed

• Includes a low extreme score

• More high than low scores

• Median is higher than mean

Measures of Variability

• Range, Variance, Standard of Deviation

• Depict diversity of distribution

• Standard deviation = √variance

  • Both relate the average distance of any score in the distribution from the mean

  • The higher the standard deviation and variance, the more spread out the distribution

z scores

• measure the distance of a score from the mean in units of standard deviation

  • Scores below mean = negative z score

  • Scores above the mean = positive z score

normal curve

• 68% fall within 1 standard deviation from the mean

• 95% fall within 2 standard deviations from the mean

• 99% fall within 3 standard deviations from the mean

Percentile

• Measure distance of a score from 0

Correlations

refer back to correlational method for more info

Correlation Coefficient

• Ranges from -1 (perfect negative correlation) to +1 (perfect positive correlation)

• 0 = no correlation

Correlations are typically graphed by a scatter plot

Line of Best Fit (Regression Line)

• Line drawn through the scatter plot that minimizes the distance of all the points from the line

Inferential Statistics

Determining whether or not findings can be applied to the larger population from which the sample was selected

Sampling Error

• The extent to which the sample differs from the population

Many different inferential statistical tests exist, such as t-tests, chi square tests, and ANOVAs

• All take into account both the magnitude of the difference and size of the sample

p value

• The probability that the difference between the groups is due to chance

  • The smaller the p value, the more significant the results

  • p value of 0.5 is the cutoff for statistically significant results

APA Ethical Guidelines

Any type of academic research must first propose the study to the ethics board or Institutional Review Board (IRB).

Animal Research

• Clear, scientific purpose

• Answer a specific, important scientific question

• Animals chosen must be best-suited to answer the question at hand

• Researchers must care for and house animals in a humane way

• Animals must be aquired legally

• Employ the least amount of suffering feasible

Human Research

• No coercion

  • Participation should be voluntary

• Informed Consent

  • Participants must know that they’re involved in research and give consent.

  • Participants may not be deceived about the nature of the study

• Anonymity or Confidentiality

  • Privacy must be protected and identities/actions must not be revealed by the researcher

• Risk

  • Participants cannot be placed at significant mental or physical risk

  • Consideration was highlighted by Stanley Milgram’s obedience studies

• Debriefing

  • After the study, participants should be told the purpose of the study and provided with ways to contact the researchers about the results