Myers’ PSYCHOLOGY Chapter 1 Thinking Critically with Psychological Science James A. McCubbin, PhD...
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Transcript of Myers’ PSYCHOLOGY Chapter 1 Thinking Critically with Psychological Science James A. McCubbin, PhD...
Myers’ PSYCHOLOGY
Chapter 1 Thinking Critically with Psychological Science
James A. McCubbin, PhDClemson University
Worth Publishers
Critical ThinkingCritical thinking does not accept arguments and
conclusions blindly.
It examines assumptions,
discerns hidden values, evaluates
evidence and assesses
conclusions.The Amazing Randi
Courtesy of the Jam
es Randi E
ducation Foundation
Limits of Intuition and Common Sense
Hindsight Bias tendency to believe, after learning an
outcome, that one would have foreseen it
the “I-knew-it-all-along” phenomenonOverconfidence
we tend to think we know more than we do
Limits of Intuition
Personal interviewers may rely too much on their “gut feelings” when
meeting with job applicants.
Taxi/ G
etty Images
How Do Psychologists Ask & Answer Questions?
Psychologists, like all scientists, use the scientific method to construct
theories that organize, summarize and simplify observations.
The Scientific Method
A theory is an explanation that integrates principles and organizes
and predicts behavior or events.
For example, low self-esteem contributes to depression.
Theory
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.
Hypothesis
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.
Research Observations
Research Process
Scientific Methods
Descriptive Method – describes something that is occurring (case studies, surveys, naturalistic observation)
Correlational Method gives information on whether there is a
relationship between two (or more) things Can NOT establish causation
Experimental Method – manipulates one variable to see if the change effects another variable Can establish causation
Description MethodsCase Study
A technique in which one person is studied in depth to reveal underlying behavioral principles.
Is language uniquely human?
Susan K
uklin/ Photo R
esearchers
SurveyA technique for ascertaining the self-
reported attitudes, opinions or behaviors of people usually done by questioning a
representative, random sample of people.
http://ww
w.lynnefeatherstone.org
Survey
Wording Effects Can change the results of a survey Should cigarette ads and pornography
be allowed on television? (not allowed vs. forbid)
False Consensus Effect tendency to overestimate the extent to
which others share our beliefs and behaviors
Survey Random Sampling
If each member of a population has an equal chance of inclusion into a sample, it is called a
random sample (unbiased). If the survey
sample is biased, its results are not valid.
The fastest way to know about the marble color ratio is to blindly transfer a
few into a smaller jar and count them.
Naturalistic Observation
Observing and recording the behavior of animals in the wild and recording self-seating patterns in a multiracial school lunch room constitute naturalistic observation.
Courtesy of G
ilda Morelli
Research StrategiesCorrelation Coefficient
a statistical measure of the extent to which two factors vary together and thus how well either factor predicts the other
Correlation coefficient
Indicates directionof relationship
(positive or negative)
Indicates strengthof relationship(0.00 to 1.00)
r = +.37
Scatterplots
Perfect positivecorrelation (+1.00)
No relationship (0.00) Perfect negativecorrelation (-1.00)
DataData showing height and temperament in people.
ScatterplotThe Scatterplot below shows the relationship between
height and temperament in people. There is a moderate positive correlation of +0.63.
Illusory CorrelationThe perception of a relationship where no
relationship actually exists. Parents conceive children after adoption.
Confirming evidence
Disconfirming evidence
Do not
adopt
Disconfirming evidence
Confirming evidence
Adopt
Do not conceiveConceive
Michael N
ewm
an Jr./ Photo Edit
Random Sequences
Your chances of being dealt either of these hands is precisely the same: 1 in 2,598,960.
Research StrategiesThree Possible Cause-Effect Relationships
(1)Low self-esteem
Depression
(2)Depression
Low self-esteem
Low self-esteem
Depression
(3)Distressing events
or biologicalpredisposition
could cause
could cause
could cause
or
or
and
Experimental Method
Like other sciences, experimentation is the backbone of psychological research.
Experiments isolate causes and their effects.
Exploring Cause and Effect
Many factors influence our behavior. Experiments (1) manipulate factors that interest us, while other factors are kept
under (2) control.
Effects generated by manipulated factors isolate cause and effect relationships.
Exploring Cause & Effect
Research Strategies
Operational Definition a statement of procedures
(operations) used to define research variables
Example-intelligence may be operationally
defined as what an intelligence test measures
Research Strategies
Replication repeating the essence of a research
study to see whether the basic finding generalizes to other subjects and circumstances
usually with different subjects in different situations
Research Strategies
Population all the cases in a group, from which
samples may be drawn for a studyRandom Sample
a sample that fairly represents a population because each member has an equal chance of inclusion
Research Strategies
Experiment the investigator manipulates one or more
factors (independent variables) to observe their effect on some behavior or mental process (the dependent variable) while controlling other relevant factors by random assignment of subjects
by random assignment of participants the experiment controls other relevant factors
Research Strategies
Double-blind Procedure both the subject and the research staff are
ignorant (blind) about whether the subject has received the treatment or a placebo
commonly used in drug-evaluation studiesPlacebo
an inert substance or condition that may be administered instead of a presumed active agent, such as a drug, to see if it triggers the effects believed to characterize the active agent
Research Strategies
Experimental Condition the condition of an experiment that
exposes subjects to the treatment, that is, to one version of the independent variable
Control Condition the condition of an experiment that
contrasts with the experimental treatment serves as a comparison for evaluating the
effect of the treatment
Research Strategies
Random Assignment assigning subjects to experimental and control conditions by chance
minimizes pre-existing differences between those assigned to the different groups
An independent variable is a factor manipulated by the experimenter. The effect of the independent variable is the
focus of the study. For example, when examining the effects of
breast feeding upon intelligence, breast feeding is the independent variable.
Independent Variable
A dependent variable is a factor that may change in response to an independent variable. In psychology, it is usually a
behavior or a mental process.
For example, in our study on the effect of breast feeding upon intelligence,
intelligence is the dependent variable.
Dependent Variable
ComparisonBelow is a comparison of different research methods.
Statistical Reasoning
Statistical procedures analyze and interpret data allowing us to see what the unaided eye misses.
Composition of ethnicity in urban locales
Describing DataA meaningful description of data is important in research. Misrepresentation may lead to incorrect
conclusions.
Statistical ReasoningMode
the most frequently occurring score in a distribution
Mean the arithmetic average of a distribution obtained by adding the scores and then dividing
by the number of scoresMedian
the middle score in a distribution half the scores are above it and half are below it
Statistical ReasoningA Skewed Distribution
15 20 25 30 35 40 45 50 90 475 710
70
Mode Median Mean
One Family Income per family in thousands of dollars
Normal Curve
A symmetrical, bell-shaped curve that describes the distribution of many types of data (normal distribution). Most scores fall near the mean.
Measures of VariationRange: The difference between the highest and lowest scores in a distribution.
Standard Deviation: A computed measure of how much scores vary around the mean.
Statistical ReasoningStatistical Significance
a statistical statement of how likely it is that an obtained result occurred by chance
Making Inferences
When sample averages are reliable and the difference between them is relatively large, we say the difference has statistical significance. It
is probably not due to chance variation.
For psychologists this difference is measured through alpha level set at 5 percent.
When is a Difference Significant?
FAQQ5. Is psychology free of value judgments?
Ans: No. Psychology emerges from people who subscribe to a set of values and judgments.
© Roger Shepard
FAQ
Q4. Is it ethical to experiment on people?
Ans: Yes. Experiments that do not involve any kind of physical or psychological harm beyond normal levels encountered in daily
life may be carried out.Milgram Experiment Replication