Chapter 2 PSYCHOLOGICAL RESEARCH

four types of thinking critically about claims

1) What is the expertise of the person making the claim?
2) What might they gain if the claim is valid?
3) Does the claim seem justified given the evidence?
4) What do other researchers think of the claim?

Deductive reasoning

results are predicted based on a general premise

Example of Deductive reasoning

All living things require energy to survive (premise), ducks are living things, therefore ducks require energy to survive (conclusion).

Inductive reasoning

conclusions are drawn from observations.

Example of Inductive reasoning

You see many fruit growing on trees and therefore assume all fruit grows on trees.

Scientific Method

The scientific method of research includes proposing hypotheses, conducting research, and creating or modifying theories based on results.

process of scientific method

1. Scientists form ideas (theories/hypotheses) through deductive reasoning.
2. Hypotheses are then tested through empirical observations and scientists form conclusions through inductive reasoning.
3. These conclusions lead to new theories and hypotheses (or more broad generalizations).

How are inductive reasoning used in science

Scientists use inductive reasoning to form theories which then generate hypotheses.

Theory

well-developed set of ideas that propose an explanation for observed phenomena.

Hypothesis

tentative and testable statement (prediction) about the relationship between two or more variables.
- Usually an (If and then) statement

Clinical or case studies

usually focus on one individual.
1) The studied individual is typically in an extreme or unique psychological circumstance that differentiates them from the general public.

Observation bias

when observations may be skewed to align with observer expectations.
1) Establishment of clear criteria to observe should help eliminate observer bias.

Naturalistic behavior

generally hidden under scrutiny or observation.

Example of Naturalistic behabior

Seeing a police car behind you would probably affect your driving behavior.
1) Through naturalistic observations, any feeling of performance or anxiety of the studied individuals is eliminated.

surveys

A list of questions that can be delivered in many ways:
1) Verbally
2) Paper-pencil
3) Electronically

What are surveys used for

Surveys can be used to gather a large amount of data from a sample (subset of individuals) from a larger population.

Archival research

method of research using past records or data sets to answer various research questions, or to search for interesting patterns or relationships

Cross-Sectional Research

Compares multiple segments of a population at a single time (such as different age groups).

Longitudinal research

Studies in which the same group of individuals is surveyed or measured repeatedly over an extended period of time.

Attrition

reduction in number of research participants as some drop out of the study over time.

Correlation

Relationship between two or more variables; when two variables are correlated, one variable changes as the other does.

correlation coefficient

number from -1 to +1, indicating the strength and direction of the relationship between variables, and usually represents by r.

Positive correlation

Two variables change in the same direction, both becoming either larger or smaller.

negative correlation

two variables change in different directions, with one becoming larger as the other becomes smaller; a negative correlation is not the same thing as no correlation

cause and effect relationship

changes in one variable cause the changes in the other variable; can be determined only through an experimental research design.

confounding variable

unanticipated outside factor that affects both variables of interest, often giving the false impression that changes in one variable causes changes in the other variable..

Example of Correlation does not indicate causation

1) As ice-cream sales increase, so does the overall rate in crime.
2) A relationship exists between ice-cream and crime but is it correlation or does one cause the other?
3) In this example, temperature is a confounding variable. As the temperature increases, ice-cream sales increase and people are more likely to be outside increasing crime rates

Illusory correlations

Seeing relationships between two things when in reality no such relationship exists.
- Illusory correlations can be involved in the formation of prejudicial attitudes that can lead to discriminatory behavior.

Confirmation bias

tendency to ignore evidence that disproves ideas or beliefs.

example of illusory correlation

Many people believe that a full moon makes people behave oddly. Research demonstrates that this relationship does not exist.

How can we establish that there is a cause-and-effect relationship

conduct a scientific experiment.

How are Hypothesis formulated

through
1) Observations
2) After reviewing previous research

Experimental group

The participants that experience the manipulated variable (group designed to answer the research question).

Control group

Participants that do not experience the manipulated variable.
- Serve as a basis for comparison and controls for chance factors that might influence the results of the study

Experimental manipulation

is the only difference between the experimental and control groups, so any differences between the two are due to experimental manipulation rather than chance.

Operational definition

description of what actions and operations will be used to measure the dependent variables and manipulate the independent variables.

Experimental bias

researcher expectations skew the results of the study.

Participant bias

participant expectations skew the results of the study.

Single-blind study

experiment in which the researcher knows which participants are in the experimental group and which are in the control group but participants do not. (Controls for participant expectations).

Double-blind Study

experiment in which both the researchers and the participants are blind to group assignments. (Controls for both participant and experimenter expectations).

placebo effect

people's expectations or beliefs influencing or determining their experience in a given situation.
1) When people are given a pill to improve their mood their mood may increase just because they believe it will.
2) To know if a medication is really having an effect or whether it us a placebo effect, the experimental group receive the medication and the control group receive a placebo treatment (a sugar pill). This is a double-blind study.
3) Any differences between the groups will be due to the medication.

Independent Variable

Variable that is influenced/controlled by the experimenter. Ideally this should be the only important difference between the experimental and control group.

Dependent variable

Variable that the researcher measures to see how much effect the independent variable had

participants

Subjects of psychological research.

Sample

A subset of individuals selected from the larger population.
- due to Populations being too large for a researcher to include everyone so samples are used.

Population

overall group of individuals that the researcher is interested in (e.g. College students

Random Sample

a subset of a larger population in which every member of the population has an equal chance of being selected.
1) This form of sampling is preferred because it is more likely that the selected participants will be representative of the larger population (sex, ethnicity, social economic status etc).

Random Assignment

Method of experimental group assignment in which all participants have an equal chance of being assigned to either group.
1) Can be achieved using statistical software or by simply flipping a coin.
2) Prevents systematic differences between groups such as gender or age

Why is random assignment important in research?

Without random assignment, an experiment cannot find a true cause-and-effect relationship. Any relationship could be due to preexisting differences between the groups.

What does random assignment do

Random assignment helps to avoid preexisting systematic differences so that any significant differences between groups can be said to be the result of the manipulation.

Manipulating variables

random assignment is required to state causation. Once randomly assigned, each group is then manipulated in some way. However, some experimental designs are more complicated.

Example of Manipulating variables

The effect of sex (male/female) on spatial memory.
1) Sex (independent variable) cannot be manipulated.
2) Males and females cannot be randomly assigned.
- This kind of an experiment is therefore called quasi-experimental.
- A cause-and-effect relationship cannot be determined from this type of experiment.

Ethics

Some questions cannot be answered using an experimental design because they would be unethical.

Example of Ethics

The effect of experiencing abuse as a child on levels of self-esteem.
1) You cannot randomly assign participants to receive abuse.
2) This would need to be studied using other approaches such as case studies or surveys.

Statistical analysis

Determines how likely any difference between experimental groups is due to chance.
- Psychologists usually discuss results as significant or non-significant.
- If the odds that the differences occurred by chance are 5% or less, then the results are significant.

Peer-Reviewed Journal article

article read by several other scientists (usually anonymously) with expertise in the subject matter, who provide feedback regarding the quality of the manuscript before it is accepted for publication.

Replications

1) Determines reliability of original research design.
2) Can include additional measures that expand on the original findings.
3) Provide more evidence to support the original finding or to cast doubt on those findings.

Why is peer review important?

1) Helps to weed out poorly conceived or executed studies.
2) Improves articles with suggested revisions.
3) Determines whether the research is described clearly enough to be replicated by other researchers.

Reliability

consistency and reproducibility of a given result.
1) Would the same test give the same results every time?
2) Do the instruments/tools used to collect data do so in consistent, reproducible ways?

Inter-rater reliability

measure of agreement among observers on how they record and classify a particular event.

Validity

accuracy of a given result in measuring what it is designed to measure.
- Does a test measure what it is meant to measure?
- A valid measure is always reliable but a reliable measure is not always valid.

Institutional Review Board (IRB)

Committee of administrators, scientists, and community members that reviews proposals for research involving human participants.
1) Exist at any research institution that receives federal support for research involving human participants.
2) Generally, IRB must approve research proposal before it can proceed.

Informed consent

A process of informing a research participant about what to expect during an experiment and then obtaining the person's consent to participate. Includes:
1) Potential risks involved
2) Implications of the research
3) Notification that participation is voluntary
4) Notification that any data collected will be kept confidential

Deception

Purposely misleading experiment participants in order to maintain the integrity of the experiment.

Debriefing

when an experiment involved deception, participants are told complete and truthful information about the experiment at its conclusion.

The Tuskegee Syphilis study

- Ethical guidelines have not always existed.
In 1932, participants were recruited in an experiment studying syphilis in black men.
- Participants who tested positive were not informed that they had the disease.
- Although no cure existed at the beginning of the study, a cure was found in 1947 (penicillin), but it was not administered to participants.
- Many participants unknowingly spread the disease and many died.

Institutional Animal Care and Use Committee (IACUC)

committee of administrators, scientists, veterinarians, and community members that reviews proposals for research involving non-human animals.

Animals in research

-90% of psychological research involving animal subjects uses rodents or birds.
-Animals make good substitutes because many of their basic processes are sufficiently similar to those in humans.
-Animals are used when the research would be unethical in human participants.
-Researchers must still aim to minimize pain or distress.