lecture 2 the science of psychology. todays outline critical thinking & science psychological...
TRANSCRIPT
Lecture 2
The Science of Psychology
Today’s Outline
Critical Thinking & Science Psychological Methods Types of data
Self report Observation
Research Design Archival Correlational Longitudinal Experimental
Methods of Psychology:Scientific Method Science starts with an attitude and a desire
for the truth
Systematic empirical study of phenomena __________: keep the bias out, include all data
and information even if it doesn’t “fit” __________: based on observable events __________: must be measurable
Short Video
What was the study? Did people believe it? What’s a placebo? Why do placebos work?
Problems with Common Sense
People see some parts of the world and miss others due to preconceptions, ability, attention, etc.)
People notice those things that fit preconceptions
People often believe to be true whatever feels good
The Scientific Method
To develop theories about the world and to test those theories using observations
Theory: An explanation Scientific theory is backed by data The scientific process
Is self correcting (theories are tested, then revised, then tested)
Theories are _________ The process is objective and public
The Science of Psychology
Separating anecdotes, folk wisdom and advice from data and conclusions!
Scientific Research is…
1. Formulating _______________
2. Testing __________ using the scientific method
3. Interpreting the results
4. Communicating the results --- realistically
The goals of science Description: What happens? Prediction: When does it happen? Explanation: Why does it happen?
Theory Causal Inferences
Intervention/Application: What could be done to help?
These all build on each other
Self Report
Self-report methods: ask participants to tell you Interviews Questionnaires Daily diary methods
Observational Data
Observational Data Observations in natural settings Laboratory-based observation
Research Designs
Archival – digging through the vaults… Correlational research – when one goes up,
what happens to the other? Longitudinal research – how do things relate
over time? Experimental research – if one is changed,
what happens to the other?
Archival Research
Researchers examine existing data that may or may not have been intended for research
Harker and Keltner (2001) used yearbook pictures to predict marital outcomes 30 years later
Archival Results
Smiling at age 20 predicted:
Correlational Research
Assess the naturally occurring associations among two variables Positive correlation
rewards are positively associated with satisfaction Negative correlation
conflicts are negatively associated with satisfaction
Correlational research
Perfect positivecorrelation (+1.00)
No relationship (0.00) Perfect negativecorrelation (-1.00)
The statistical concept of a “correlation coefficient (r)”
Correlation does not imply causation!
Three possible interpretations of any correlation
Pros and Cons of Correlational Research (descriptive) Advantages
Disadvantages
Longitudinal Research
Data collected at 2 or more time points
Associations among variables across time How are feelings of love across time
associated with divorce?
Longitudinal Research
Associations among variables within a day How does a partner’s behavior during the day
influence feelings of commitment at night?
Pros and Cons of Longitudinal
Advantages
Disadvantages
Experimental Research
Manipulate one variable to see if it causes changes in another variable.
Does arousal lead to greater liking?
A B
Testing the WHATs and WHYs
1:1 correspondence If you pour x into y, you know x caused the
explosion If you pour x and z into y, you don’t know what
caused the explosion Random Assignment
In large enough samples, characteristics will be equally distributed
Experimental: Video Games & Violence
What is an independent variable? What is a dependent variable? What is the point of experiments? What is random assignment? How are differences controlled?
Pros and Cons of Experimental
Advantages
Disadvantages