Download Thinking Critically with Psychological Science

Thinking
Critically with
Psychological
Science
Chapter 1
The Scientific Attitude
To sift reality from fantasy
requires a scientific attitude.
Researchers must be
curiously skeptical and yet
humble at the same time!

Limits of Intuition &
Common Sense



Hindsight Bias – “Knew
it all along”
Overconfidence – We
tend to think we know
more than we do.
False Consensus
Effect – believing that
everyone agrees with
our line of thinking
Research Strategies
 Population
 Sampling
Descriptive Research Methods
 Descriptive
Methods are used to observe
and record behavior only

The Case Study – an extremely detailed
study on one or more individuals in order to
make generalizations about others.
Sometimes called an interview study.
Descriptive Research Methods


Survey
Naturalistic Observation
Perspective
Depression
Overeating
Behavioral
Learned helplessness –
receiving constant
negative feedback from
others causes you to feel
this way all the time
Parents told the child to clear
their plate before they could
have dessert – now they do
not notice internal cues
about hungry
Biological
Cognitive
Humanistic
Psychodynamic
Social
Perspective
Depression
Overeating
Behavioral
Learned helplessness –
receiving constant
negative feedback from
others causes you to feel
this way all the time
Parents told the child to clear
their plate before they could
have dessert – now they do
not notice internal cues
about hungry
Biological
Linked with lower levels
of serotonin
Eating carbohydrates can
cause a release of serotonin
which causes a pleasure –
also, lesions on ventromedial
hypothalamus have been
linked to overeating
Cognitive
Humanistic
Psychodynamic
Social
Correlation
 Describing
behavior is the first step toward
predicting it. When surveys and
naturalistic observations reveal that one
trait or behavior accompanies another,
we say the two correlate.
 Correlation reveals how closely the two
things link together and how well it
predicts the other.
Correlation



Positive Correlation: score
between 0 & +1. The two
things either increase or
decrease together (direct
relationship).
Negative Correlation: scored
with a negative (-) sign; means
there is an inverse relationship.
As one thing increases the
other decreases.
Correlation Coefficient – a
statistical measure of the
extent to which 2 factors vary
together and thus how well
either factor predicts the other



+ or – indicates the direction of
the relationship
0.00 to 1.00 indicates the
strength of the relationship
r= +.68
Correlation

Illusory Correlation: statistics can help us see what
the naked eye sometimes misses. Correlations not
only make visible relationships that we might
otherwise miss, they also restrain our “seeing”
nonexistent relationships.

We pay attention to sequence, but it may not be
a correlation. Bizarre events happen. Correlation
Does Not Prove Causation!

https://www.youtube.com/watch?v=8B271L3NtA
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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.


Random selection of participants
Random assignment of groups/conditions
Experimentation
 Independent
variable: the
experimental factor you manipulate;
the treatment itself.

Example: Music, medication
 Dependent
variable: the behavior
measured; the factor that might be
affected by changes in the
independent variable.

Example: Behavior on a scale 1-5 (for best
results make the DV quantitative)
Experimentation

Experimental condition/group: The condition
that exposes subjects to one version of the
independent variable.

Control condition/group: A condition identical
to the experimental one, except the
independent variable has a different value,
such as zero. They could be given a placebo
depending on the nature of experiment.
Common Flaws in Research
 Sampling
 exists
Bias
when a sample is not representative of the
population
 Placebo
Effects
 Experimental
alone
 Participant
a
results caused by expectations
Bias
tendency for participants to respond in a
certain way because they know they are being
observed (Hawthorne Effect) or they believe
they know what the researcher wants.
 Researcher
 occurs
Bias
when a researcher’s expectations or
preferences about the outcome of a study
influence the results obtained.
 Confounding
Variables…
Descriptive Statistics:
Central Tendencies



Median: is the ½ mark; half of the scores fall above and half
fall below.
Mode: the most frequently occurring score in a distribution
Mean: the arithmetic average of a distribution which is
obtained by adding the scores and then dividing by the
number of scores.
Remember, there may be a couple of high or low scores
interfering with the data.
Measures of Variance
 Range
– uses the high and low extremes
 Standard deviation – a computed
measure of how much scores vary around
the mean score; it gauges whether scores
are packed together or dispered
Descriptive Statistics
 Normal
curve is a graph of frequency
distribution shaped like a symmetrical, bellshaped curve; a graph of normal
distribution.
In a normal distribution, about 68% of the scores are within one
standard deviation of the mean and about 95% of the scores are within
two standards deviations of the mean.
Descriptive Statistics
 In
a normal distribution, the median is
equivalent to the mean.
 In a positively skewed distribution, the
mean is higher than the median.
 In a negatively skewed distribution, the
median is higher than the mean.
Positive
negative
Experiments on People
 In
the past, researchers did not have mandated
guidelines when doing experiments, and some
would use experimental procedures that were not
ethical.
 Ethical principles developed by the APA urge
investigators to:





Obtain the informed consent of potential participants.
Protect them from harm and discomfort.
Treat information about individuals confidentially.
Fully explain the research afterward (debrief).
Do not be deceitful.
Experimentation on Animals
 Animal
experiments have led to many
treatments for humans. They have also
led to heated debates. Ethical guidelines
are in place for the care and justified use
of animals.
 The APA guidelines mandate ensuring the
“comfort, health, and humane treatment”
of animals, and of minimizing
“infection, illness, and pain
of animal subjects.”
Key Ethics Principles to
understand:
 Informed
consent – they must be given a
statement that informs them of procedures, risks,
benefits, and the right of the participant not to
participate or to withdraw from the study without
penalty
 Deception – they cannot be deceived about
significant aspects that would affect their
willingness to participate
 Debriefing – after the participant finishes, they are
told of the nature of the results and conclusions