Video link: http://www.learner.org/discoveringpsychology/02/e02expand.html
A Theory is an explanation that integrates principles and organizes and predicts behavior or events.
For example, low self-esteem contributes to depression.
Theories are NOT the product of guesswork! They are highly researched, rigorously tested frameworks.
NOTE: Our text does not use the term generalizability. This term is used on the AP EXAM. It refers to what degree the results of a study can be applied to or replicated with different types of populations.
A Hypothesis is a testable prediction, often prompted by a theory, to enable us to accept, reject or revise the theory.
People with low self-esteem are apt to feel more depressed.
TROUBLESHOOTING: A hypothesis is NOT an educated guess.
In psychology, a hypothesis is a statement of a relationship between or among variables. (not in text)
So how could we research that People with low self-esteem are apt to feel more depressed?
Research would require us to administer tests of self-esteem and depression. Individuals who score low on a self-esteem test and high on a depression test would confirm our hypothesis.
NB – this is not an experiment.
To reduce bias psychologists report their research with operational definitions.
An operational definition states how the variable is observed and measured. An operational definition must be manageable.
Operational definitions allows others to replicate (repeat) the observations. Why?
OPERATIONAL DEFINTIONS ACTIVITY
Determine an operational definition for each underlined variable.
Remember an operational definition is observable and measurable.
The teacher wants to find a way to help make Billy act more friendly toward other children.
A psychologist wants to know if the new form of psychotherapy will make people less depressed.
A student wants to find a way to study more efficiently.
Does this drug help people overcome tiredness?
Boys show more affection for their fathers than their mothers.
People dream more if they have a big meal before going to sleep.
7. College athletes are not as smart as regular students.
8. Overall senior girls are prettier than sophomore girls.
9. How does grade point average affect a person’s sense of humor?
Get out of your seats. You may not sit down or lean against anything.
Examples: Observing and recording the behavior of animals in the wild; recording self-seating patterns in a multiracial school lunch room.
Courtesy of Gilda Morelli
Describes, does not explain
Often used by ethologists such as Jane Goodall
Behavior changes when you know you are being watched
Observations may be distorted by what the experimenters expect to see.
Other advantages, disadvantages?
Case studies, surveys, and naturalistic observation describe behaviors.
Correlation = relationship between variables
Variables = the specific factors or characteristics that are manipulated and measured in research
Evidence should be evaluated in terms of reliability and validity
Reliability: repeatable (replication)
Validity: accurately assesses topic
Scatterplots: represent the values of two variables; indicates correlation or relationship between the variables
Measured by the correlation coefficient, a statistical measure of relationship. The extent to which two factors vary together, and thus of how well either factor predicts the other.
Scatterplot is a graph comprised of points that are generated by values of two variables. The slope of the points depicts the direction, while the amount of scatter depicts the strength of the relationship.
When one trait or behavior accompanies another, we say the two correlate.
(positive or negative)
(0.00 to 1.00)
Correlation Coefficient is a statistical measure of the relationship between two variables.
Strength of the relationship is indicated by the number.
The closer it is to zero, the weaker the relationship
The closer it is to one (plus or minus), the stronger the relationship
+.8, -.2, -.9, +.3
Guys – if you want keep your hair, don’t get married
Among men, the number of years they are married positively correlates to baldness
So… marriage causes baldness in men, right?
Correlation does not mean causation!!!
The perception of a relationship where no relationship actually exists. When we believe there is a relationship we are likely to notice and recall instances that confirm our belief: Parents conceive children after adoption.
Do not conceive
Michael Newman Jr./ Photo Edit
Examples of Illusory Correlations:
It always rains when …
The phone always rings when…
More serious implications?
The Point to Remember:
When we notice random coincidences, we may forget that they are random and instead see them as correlated. Thus we can easily deceive ourselves by seeing what is not there.
Michael Newman Jr./ Photo Edit
The Point To Remember:
A correlation coefficient helps us see the world more clearly by revealing the extent to which two things relate.
r = +.61
Correlation and Causation
Very important to remember:
Correlation does necessarily prove causation!
Order in Random Events
Given random data, we look for order and meaningful patterns.
Your chances of being dealt either of these hands is precisely the same: 1 in 2,598,960.
Order in Random Events
Given large numbers of random outcomes, a few are likely to express order.
Angelo and Maria Gallina won two California lottery games on the same day.