Psyc103 – Introduction to Psychological Science

Chapter 02Research Methods

exercise

• If you could research anything you wanted, what would you be interested in trying to understand better?

• THINK ABOUT IT and then come up with your own research question.

scientific inquiry

• Scientific investigation involves three distinct levels:

Theory

Question/Hypothesis

ResearchBut why do we investigate psychological processes in this manner?

science as a way of knowing

• Our individual and collective goal is to build a body of knowledge.– Facts – knowing that p.– Skills – knowing how to p.

belieftrue

justified

What is it to know that p? Knowledge =

science as a way of knowing

• There are three common ways of knowing

AUTHORITY REASON EXPERIENCE

LIMITATIONS: opportunities for bias, motivated by power, desire to maintain status quo, lack of sufficient information….

***** SCIENCE *****

Requires: clear standards for authority, open dissemination of methods and data, shared assumptions, relicatable studies, data-driven conclusions, objectivity (removal of personal bias), theories that can be disproven…

science as a way of knowing

• What are the limitations of science?

Objectivity = a view from NOWHERE You cannot disentangle subject and object. You cannot draw meaningful generalizations. Only WEIRD people are allowed to contribute.*** Inter-subjectivity = a

view from EVERYWHERE ***

?? Response ??

Conducting Research

the “five step” process

Psychological Theory

1. Ask a research question.2. Develop a hypothesis.3. Construct a methodology to test your hypothesis.4. Draw a conclusion.5. Share your findings.

research questions

Does god exist?• Is this a good research question?

!! NO !!Good research questions must involve something that can be empirically defined and measured.

i<clicker

• Which of these is the best research question?– A) Alcoholic parents tend to neglect their

children more than non-alcoholic parents.– B) What factors influence high school dating?– C) Does the frequency and graphic quality of

violence in video games influence levels of anti-social thinking in adolescent males?

– D) How much longer until class is over?– E) B & C are equally good.

definition and measurement

• Operational definition– the description of the variable of interest in

measurable terms.

• So, how might we operationally define?– Aggression– Happiness

• Measurement– Device used to detect the

events/phenomena to which the operational definition refers.

types of measurement

• Subjective measures– Introspective reports– Survey/Questionnaire

• Objective measures– Standardized testing– Naturalistic observation

• Physiological measures– fMRI, galvanic skin response– Levels of hormones,

neurotransmitters

Are physiological measures subjective or objective measures?

A) subjectiveB) objectiveC) both

exercise

• What would be the variables involved in your research question?

• How would you operationally define them?

• How would you measure them?– Can you think of both a subjective and

an objective way of measuring them?

developing hypotheses

• Developing a hypothesis: – Consider your research question.– What do you think you’ll find?

• Why?– That is, what is your

(theoretical/conceptual/empirical) justification for you hypothesis?

testing hypotheses

• How are you going to test your hypothesis?

• Non-experimental Design– Observation of variables of interest

• Experimental Design– Manipulation of variables of interest

non-experimental designs

• Systematic Observation– Naturalistic– Structured

• Self-report Survey– Clinical– Structured

• Qualitative– Case study – in-depth study of individual– Ethnography – in-depth study of culture

Question: Why choose a survey over an observation?

design considerations

• Validity• Being able to draw accurate inferences

(conclusions) about what you are studying from your measurements

• Invalid in definition– Examples?

• Invalid in detection (measurement)– Examples?

i<clicker

If I asked college students and mature adults to rate on a scale how much fun they have ever day and I found college students rated their level of fun much higher, could I then draw the conclusion that college students are happier than mature adults?– A) yes– B) no

• Why? • Issue of invalid definition.

If I was interested in studying freshman college students’ general anxiety levels and so I polled all of my Intro students using a standard anxiety scale at the beginning of class right before they took an exam, could I draw conclusions about general levels of anxiety from those measurements? – A) yes– B) no

• Why?• Issue of invalid detection.

other considerations

• Internal validity– Study was designed so that you were able

to draw accurate inferences about causal relation between independent and dependent variables.

• External validity– Study was designed so that your

independent and dependent variables are defined in natural/realistic way.

• You can have internal validity but not have external validity – why?

design considerations

• Reliability• The tendency for measurement to produce the same results

when used in the same way (or under the same conditions).– Type 1 error (false positive)– You want a measurement that is stable enough that it won’t

detect changes in your variable when changes haven’t actually occurred.

• Power• The tendency for measurement to produce different results

when used in different ways (or under different conditions). – Type 2 error (false negative)– You want a measurement that is sensitive enough to detect

changes in your variable when changes actually occur…

i<clicker

• You want a measurement that is sensitive enough to detect changes in your variable when changes actually occur…

• This is an issue of:– A) power– B) reliability

• You also want a measurement that is stable enough that it won’t detect changes in your variable when changes haven’t actually occurred.

• This is an issue of:– A) power– B) reliability

population and sample

• You are asking a question about behavior in a given population– It is difficult (if not

impossible) to ever study an entire population – so what do we study instead?

teenagers

population and sample

• You are asking a question about behavior in a given population– It is difficult (if not

impossible) to ever study an entire population – so what do we study instead?

• a sample.

teenagers

population and sample

• How do we make sure that we can accurately generalize from a sample to a population?

• We choose a representative sample.– controlled sampling– random sampling

i<clicker

• Which makes for a good sample?

– A) when it is chosen to match the demographics of the population as closely as possible

– B) when it is randomly selected from the population

– C) both.

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describing variables

•Central tendency

•mode—most frequent

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describing variables

•Central tendency

•mode—most frequent

•mean—average

Μ = 3.27

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describing variables

•Central tendency

•mode—most frequent

•mean—average•median—

middle

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describing variables

•Central tendency•mode—most

frequent•mean—average•median—middle•Each of these

tells us something different about our data.

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describing variables

•Variability– range

7 – 1 = 6

normal distribution

• Many things tend to be normally distributed in a given population.

• So, we should expect most people to fall somewhere close to the middle, with the extreme cases being less frequent.

IQ is normally distributed.

mean

Income is one thing that is not normally distributed.

A) TrueB) False

Can you think of others?

relationships between variables

• What does it mean for two things to be correlated?

• It means that the two things are co-related– A change in one thing is associated with a

change in the other thing.

• Examples A change in the sun’s location in the sky is

correlated with a change in temperature. A change in income is correlated with a

change in level of education.

relationships between variables

• A is correlated with B– Positive relationship: A+ B+, A- B-– Negative relationship: A+ B-, A- B+

• Pearson correlation coefficient r = 1 to -1

relationships between variables

• As a person gets angrier, they also get more violent.– A) Positive – B) Negative

• Positive. As anger increases, violence increases.

• As a person gets older, they start to remember fewer vocabulary words.– A) Positive – B) Negative

• Negative. As age increases, vocabulary memory decreases.

• As calorie consumption drops, people have less energy.– A) Positive– B) Negative

• Positive. As calorie consumption decreases, energy levels decrease (movement is happening in the same direction).

relationships between variables

Ultimately, we are typically interested in whether or not one variable causes another.

T/F: All variables that are causally related are correlated.

T/F: All variables that are correlated are causally related.

Ask Yourself!

• A researcher compares older adults with chronic heart disease to those with no major health problems and finds that the first group scores lower on mental tests. Can the researcher conclude that heart disease causes a decline in intellectual functioning in late adulthood?

• A) yes• B) no

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correlation vs. causation

•Two variables are correlatedX Y

•Three possible relationships

X causes Y

Y causes X

Z causes both X and Y

– with correlation, we cannot know which it is.

third variable problem

+

third variable problem

+

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experimental design

•To establish causation, we must conduct an experiment.

•Experimentation requires manipulation.•A B

•A is the independent variable -- manipulated

• e.g., amount of television violence watched

•B is the dependent variable -- measured• e.g., amount of aggressive behavior exhibited

experimental design

Violent TV

Non-violent TV

?

exercise

• Consider your own research question.

• Come up with a non-experimental design to investigate it.

• Can you also come up with an experimental design?

experimental design

• In the case of a 3rd variable, you have two choices:

• Manipulate and measure x & y, while controlling for z.

or• Manipulate and

measure x, y, & z.

randomization (controls for the 3rd variable)

• used when z is not important for the study

selected groups (measures the influence the of 3rd variable)

• Used when z is important for the study

Adult supervision No adult supervision

tracking development

• Cross sectional• Benefits – cheap way to capture change over

time• Problems – cohort effect and other group

differences• Longitudinal• Benefits – confidence that change being captured

is genuine change• Problems – reduction of sample size and learning

effect• Cross-sequential

cross-sequential

Time 1 Time 2

2nd

4th

6th

4th

6th

8th

cross-sequential

Time 1 Time 2

2nd

4th

6th

4th

6th

8th

Ask Yourself! How do cross-sequential designs reveal any cohort effects?

other considerations

• Biases in observation– Participant biases

• Demand characteristics

– Observer biases• Confirmation bias

Double-blind experiments

other considerations

• Ethical practices– Informed consent– Debriefing– Special considerations for children

• Are there limits to what we should study– non-experimentally?– experimentally?

final steps

• Drawing conclusions– What kinds of conclusions can you

draw?– Can you generalize to a population?

• How broad of a population?

– Limitations

• Sharing your findings– Conference presentations– Publications