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Research Methods in Psychology

Observation

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Observational Research

Researchers cannot observe• all of a person’s behavior

• all people’s behavior

Researchers can observe• samples of individuals

• samples of behavior at particular times• samples of different settings and conditions

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Observational Research

Goal of samples• represent larger population of

behaviors people settings and conditions

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Observational Research

Example:• In a typical week, how many hours of

television do you watch? What is the average number of hours for the

class?

• Is this average representative of the number of hours of TV watched by all students on campus? all college students? all people?

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Observational Research

Use data from a sample to represent the population• “generalize” the findings from sample to

population

External validity• extent to which a study’s findings may be

used to describe people, settings, conditions

• beyond those used in the study

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Observational Research

Generalize findings• sample must be representative of population

is sample similar to population? do we know characteristics of entire population?

Psychology studies with college student samples• are psychology students representative of

larger population?

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Sampling Behavior

Extent to which observations may be generalized (external validity)• depends on how behavior is sampled

Two methods• time sampling• situation sampling

Goal: obtain representative sample of behavior

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Sampling Behavior, continued

Time Sampling• choose time intervals for making observations

systematic random

• don’t use time sampling for observing behavior during rare events (e.g., hurricane) event sampling

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Sampling Behavior, continued

Situation Sampling• choose different settings, circumstances,

conditions for observations• enhances external validity• use subject sampling to observe some people

within a situation

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Classification of Observational Methods

Categories based on intervention by researcher• Observation without Intervention• Observation with Intervention

Categories based on methods for recording behavior• comprehensive record• selected behaviors

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Observation without Intervention

Naturalistic Observation• observation in natural (real-world) setting without

attempt to intervene or change situation• use when ethical considerations prevent experimental

manipulation

Goals• describe “normal” behavior, examine relationships

among naturally occurring variables• establish external validity of lab findings

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Observation with Intervention

Most psychological research involves intervention

Three methods in natural settings• participant observation• structured observation• field experiment

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Observation with Intervention, continued

Participant observation• observer is active participant in the natural

setting he or she observes undisguised: people know they’re being observed disguised: people don’t know they’re being

observed

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Observation with Intervention, continued

Problems with participant observation• Reactivity

when people change their usual behavior because they’re being observed

disguised participant observation controls reactivity

• Observers lose objectivity or become too involved in situation

• Observers influence behavior of people they’re observing

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Observation with Intervention, continued

Structured observation• set up (structure) specific situation in order to

observe behavior• used when behavior is difficult to observe as it

naturally occurs• researchers use confederates to structure

situations• problems: when observers don’t follow same

procedures across observations

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Observation with Intervention, continued

Field Experiment• manipulate independent variable in natural

setting and observe behavior (dependent variable) two or more conditions to compare (IV) often use confederates to create conditions strive for control in natural setting

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Recording Behavior, continued

Qualitative Records• Narrative records: complete reproduction of

behavior (video, audio, field notes)• made during or soon after behavior occurs• carefully train observers• advantage: can review record often• disadvantage: costly, time-consuming

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Recording Behavior, continued

Quantitative Records• Selected behaviors

• Requires decision regarding how to measure behavior (e.g., frequency, duration)

• checklists, electronic recording and tracking

Measurement Scales• Four levels for quantifying behavior

nominal, ordinal, interval, ratio

Correlational Resarch

Collects a set of facts organized into two or more categories• measure parents disciplinary style• measure children’s behavior

Examines the relationships between 2 or more categories e.g., more democratic parents have children

who behave better

Correlational Research

Correlation CANNOT prove causation• Do democratic parents produce better

behaved children?• Do better behaved children encourage

parents to be democratic?

May be an unmeasured common factor • e.g., good neighborhoods produce

democratic adults and well behaved children

Correlational Research

Scatterplots – graphed cluster of dots, each of which represents the values of two variables• See pg. 27 for examples

Correlation Coefficient – a statistical measure of relationship• Statistical measure of the extent to which

two factors vary together, and thus of how well either factor predicts the other.

Correlational Research

Direction of a Correlation

(slope of the points) Positive Correlation – as one variable

goes up, the other variable tends to go up (so as one goes down, the other goes down) – max. +1.00

Negative Correlation – as one variable goes up, the other tends to go down, the inverse is also true – min. -1.00

No Correlation – correlation is 0.0

Strength of Correlation

(amount of scatter) The higher the correlation coefficient is

(without regard to sign) the stronger the correlation is.

The stronger the correlation is, the better one variable can predict the other.

Correlational Research

Correlations make visible relationships that we might otherwise miss.

They also restrain our “seeing” relationships that actually do not exist – illusory correlations – perception of a relationship where none exists

(e.g., superstitious beliefs)

Believe – likely to notice and recall

Correlational Research

A little note about correlation –

CORRELATION DOES NOT PROVE

CAUSATION!!

Primary Research: Experimental Research

Experiment • Investigator manipulates a variable under carefully controlled conditions and observes whether changes occur in a second variable• Used to detect cause-and-effect relationships

Conditions that make a true experiment• Manipulation of independent variables• Random assignment into experimental conditions (experimental conditions & control)

Primary Research: Experimental and Control Groups

Experimental group•Subjects who receive some special treatment in regard to the independent variable

Control group•Subjects who do not receive the special treatment given to the experimental group

LOGIC: If the 2 groups are identical except for the variation created by the manipulation of IV, then any

differences between groups must be due to manipulation of the IV

Sample

ExperimentalControl

Measure DV

Example of Experimental Design

Advantages and Disadvantages of Experimental Research

+ permit cause-and-effect conclusions

- lab experiments tend to be artificial

- cannot be used to explore some research questions

•Participants must be and are selected for different conditions from pre–existing groups

•Levels of the IV are/may be selected from pre–existing values and not created through manipulation by the researcher

•Unlike true experimental designs where participants are randomly assigned to experimental and control groups, with quasi–experimental designs they are NOT

•Quasi–experiments DO NOT permit the researcher to control the assignment of participants to conditions or groups

Primary Research Field Experiments: Quasi-Experiments