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Research Methods: Thinking Critically With Psychology
Transcript of Research Methods: Thinking Critically With Psychology
Thinking Critically with Psychological Science
"Life is lived forwards, but understood backwards"
- Philosopher Soren Kierkegaard
The Scientific Method
In science, everything tends to start with an
; something we notice that makes us pause to think.
In order to summarize and evaluate our data, we must know how to measure it.
Measures of Variation
In order to test our hypothesis, we must decide what we are testing for. Experiments examine the effect of
) on some
measurable behavior or outcome
(known as a
This is also known as
: the tendency to believe, after learning an outcome, that one would have
it. This is because
describes what HAS happened than what WILL happen.
Next, we come up with an
(or a question) based on that observation that we can test.
is our next step; which is an educated guess or a testable prediction we can make.
(a theory =/= a guess or hypothesis)
Once we know what we're testing, we can
Once we've got our data, we need to
it to see what our experiment tells us.
Finally, we make a
where we either accept or reject our hypothesis based on the data.
is the arithmetic average (the sum of all the scores divided by the number of scores)
Just like on a highway, the
is in the middle (but you must first organize all the numbers from smallest to largest in order to find it)
is the most frequently occurring number (the one that shows up the most)
of scores is the gap between the highest and lowest score (a crude estimate of variation).
The more useful standard for measuring how much scores deviate is the
(which is a computed measure of how much scores vary around the mean score)
Large numbers of data (heights, weights, intelligence) often form a symmetrical, bell shaped distribution. Most cases fall near the mean, and fewer cases fall near either extreme. we call this type of curve the
the standard deviation (SD), the
the curve. The
the SD, the
are factors that can
potentially influence the results
of the experiment. We try to control for this by doing
when dealing with people or animals.
(like the name implies)
are things we keep the same
in the experiment to
the amount of confounding variables.
No single experiment is conclusive.
is when scientists assign participants to experimental and control groups by
This minimizes preexisting differences between those assigned to the different groups.
participants are also uninformed
about what treatment, if any, they are receiving
. This is an example of an experimental group:
one group receives the treatment, and a contrasting control group does not receive the treatment
or receives a
double-blind procedure, neither the participants or the research assistants
collecting the data will
what group is receiving treatment (this helps protect against
just by thinking
you're getting treatment to boost your spirits, relax your body, and relieve your symptoms. This is known as the
, and is well documented in reducing pain, depression and anxiety.
Observation of Behavior
There are several different ways psychologists observe and describe behavior.
The Case Study:
This is among one of the oldest research methods. Case studies
examine one individual in depth
in hopes of revealing things true of us all. They often suggest directions for further study, and they show us what can happen.
...But individual cases can
us if the individual being studied is
The survey method looks at
many cases in less depth.
Researchers do surveys when wanting to estimate, from a
of people, the attitudes or reported behaviors of a
asking questions is tricky
, and the answers often depend on the ways questions are worded and the way respondents are chosen.
For instance, people are much more
to approve "
" certain things rather than "forbidding" or "censoring" them.
Remember: before accepting survey findings, think critically about the
sample and the sample size
(but you cannot compensate for an unrepresentative sample by simply adding more people)
The Naturalistic Observation:
The naturalistic observation method
records behavior in natural environments
. This can range from watching chimpanzee societies in the wild, to unobtrusively videotaping (and later analyzing) parent-child interactions in different cultures.
Like the case study and survey methods,
do not EXPLAIN behavior, they just
it. Think of them as snapshots of everyday life that do not control for all the factors that may influence behavior.
behavior is the first step to
it. Surveys and naturalistic observation often show us that
one trait or behavior is related to another
. In such cases, we say the two
A statistical measure (the
) helps us figure how closely two things
together, and thus how well either one
of possible correlations, which can go from a perfect positive (+1) to a perfect negative (-1). Each dot represents the
of two variables.
A correlation is
if two sets of scores (such as height and weight), tend to
rise or fall together
A correlation is
if two sets of scores
(one set going up as the other goes down). An example would be temperature and elevation.
, has a coefficient near zero.
Correlation does NOT prove causation!
Although correlation indicates the
of a cause-effect relationship, it does not prove it.
In addition, when we notice random coincidences, we may forget that they are random and instead see them as correlated. This can result in an
Knowing the value of an appropriate measure of central tendency is helpful, but it is also important to know about the
amount of variation
in the data; how similar or diverse the numbers are.
“I walk on x, fly on y”
(I = independent variable, therefore I.V. goes on x axis)
Independent variable starts with “I”, it’s what * I * change
More fun with the placebo effect
of a variable is the
specific way in which it is measured
in that study. For example, a researcher measuring happiness and depression in college students decides to use a ten-question happiness scale to measure positive outlook in her subjects. In other words,
her operational definition of happiness in this case is a given subject's score on the test.
Here are the most important
and considerations that psychologists need to follow in their experiments:
- the participant is given a brief explanation of the experiment and their responsibilities
- participants' identity must be kept confidential unless they give explicit permission
- if the experimenter must lie to the participant about the true nature of the study, be sure it does not cause physical or emotional distress
- if deception has taken place, the participant must be informed of the true purpose of the experiment once it is over
Protection from Harm
- any situation that may result in significant physical or psychological harm must be avoided