Chapter 2: Methods

hindsight bias

hindsight bias

People have the tendency upon hearing about research findings (and many other things) to think that they knew it all along; this tendency is called

Basic research

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

hypothesis

expresses a relationship between two variables.

Variables

are things that can vary among the participants in the research.

theory

aims to explain some phenomenon and allows researchers to generate testable hypotheses with the hope of collecting data that support the theory.

Operational definitions

When you operationalize a variable, you explain how you will measure it.

valid

when it measures what the researcher set out to measure; it is accurate.

reliable

when it can be replicated; it is consistent.

participants

The individuals on which the research will be conducted are called

sampling

the process by which participants are selected is called

sample

(the group of participants)

random selection

is that every member of the population has an equal chance of being selected.

Stratified sampling

is a process that allows a researcher to ensure that the sample represents the population on some criteria.

Laboratory experiments

are conducted in a lab, a highly controlled environment

field experiments

are conducted out in the world.

experiment

allows the researcher to manipulate the independent variable and control for confounding variables.

Assignment

is the process by which participants are put into a group, experimental or control.

Random assignment

means that each participant has an equal chance of being placed into any group.

participant-relevant confounding variables

The benefit of random assignment is that it limits the effect of

group matching

If one wanted to ensure that the experimental and control groups were equivalent on some criterion (e.g., sex, IQ scores, age), one could use

Situation-relevant confounding variables

can also affect an experiment.

Experimenter bias

is a special kind of situation-relevant confounding variable.

double-blind procedure

Experimenter bias can be eliminated by using a

single blind

occurs when only the participants do not know to which group they have been assigned; this strategy minimizes the effect of demand characteristics as well as certain kinds of response or participant bias.

social desirability

One kind of response bias, the tendency to try to give answers that reflect well upon them, is called

Hawthorne effect

Merely selecting a group of people on whom to experiment has been determined to affect the performance of that group, regardless of what is done to those individuals.

placebo effect

This technique allows researchers to separate the physiological effects of the drug from the psychological effects of people thinking they took a drug

counterbalancing

Sometimes using participants as their own control group is possible, a procedure known as

correlation

expresses a relationship between two variables without ascribing cause.

positive correlation

between two things means that the presence of one thing predicts the presence of the other.

negative correlation

means that the presence of one thing predicts the absence of the other.

survey method

An even more popular research design is the

Naturalistic Observation

The goal of naturalistic observation is to get a realistic and rich picture of the participants’ behavior.

case study method

is used to get a full, detailed picture of one participant or a small group of participants.

Descriptive statistics

simply describe a set of data.

frequency polygons

Frequency distributions can be easily turned into line graphs called

central tendency

with at least one group of statistical measures called measures of

extreme scores or outliers

The mean is the most commonly used measure of central tendency, but its accuracy can be distorted by

positively skewed

When a distribution includes an extreme score (or group of scores) that is very high, as in the car example above, the distribution is said to be

negatively skewed

When the skew is caused by a particularly low score (or group of scores), the distribution is

Measures of variability

are other types of descriptive statistical measures.

Z scores

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

percentiles

indicate the distance of a score from 0.

correlation

measures the relationship between two variables.

correlation coefficient

The strength of a correlation can be computed by a statistic called the

scatter plot

A correlation may be graphed using a

line of best fit, or regression line

is the line drawn through the scatter plot that minimizes the distance of all the points from the line.

inferential statistics

is to determine 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 is known as

APA Ethical Guidelines

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

No coercion

Participation should be voluntary

Informed consent

Participants must know that they are involved in research and give their consent.

Anonymity or confidentiality

Participants’ privacy must be protected.

Risk

Participants cannot be placed at significant mental or physical risk.

Debriefing

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