2 - Methods in Psychology Flashcards
Dogmatists
Thought the best way to understand illness was to develop theories about the body’s functions
Empiricists
Thought the best way to understand illness was to observe sick people
Empiricism
The belief that accurate knowledge can be acquired through observation
Scientific Method
Procedure for finding truth by using empirical evidence
Theory
Hypothetical explanation of natural phenomenon
Rule of Parsimony
The simplest theory that explains all the evidence is the best one.
Hypothesis
Falsifiable prediction made by a theory (ex: God created the earth is not a hypothesis because it is impossible to prove wrong)
Why can theories be proven wrong but not right?
Hypothesis: bats never fly upside down
You can see one bat fly upside down and prove that theory wrong, but you can never see all the bats that have ever existed and will ever exist.
Empirical Method
A set of rules and techniques for observation
What makes humans so difficult to study?
Complexity, variability, reactivity
What methods have scientists developed to meet challenges of studying humans?
Methods of observation: allow them to determine what people do
Methods of explanation: allow them to determine why people do it
Operational Definition
A description of a property in concrete, measurable terms
Instrument
anything that can detect the condition to which an operational definition refers
Validity
The goodness with which a concrete event defines a property
Reliability
Tendency for an instrument to produce the same measurement whenever it is used to measure the same thing.
Power
An instrument’s ability to detect small magnitudes of the property
Demand Characteristics
Those aspects of an observational setting that cause people to behave as they think someone else wants or expects
Naturalistic Observation
A technique for gathering scientific information by unobtrusively observing people in their natural environments
Ways to avoid demand characteristics
- Allow people to respond privately or anonymously
- Measure behaviours that cannot be easily influenced under a person’s voluntary control
- Keep people from knowing the true purpose of the observation
Observer Bias
Expectations can influence observations and expectations can influence reality
Double Blind
An observation whose true purpose is hidden from both the observer and the person being observed
Frequency Distribution
A graphic representation of measurements that can be arranged by the number of times each measurement was made
Normal Distribution
(aka Gaussian distribution) Mathematically defined distribution in which the frequency of measurements is highest in the middle and decreases symmetrically in both directions
Central Tendency
Central value or typical value
Three Descriptors of Central Tendency
Mode, mean, media
Mode
The value of the most frequently observed measurement
Mean
the average value of all measurements
Median
the value that is in the middle, ie: greater than or equal to half of the measurements and vice versa
Range
the value of the largest measurement in a frequency distribution minus the value of the smallest measurement
Standard Deviation
A statistic that describes the average difference between the measurements in a frequency distribution and the mean of that distribution (in other words, on average, how far are the measurements from the center of the distribution?)
Correlation
Pattern of covariation; comparing the patterns of variation in a series of measurements
Correlation Coefficient
A mathematical measure of both the direction and strength of a correlation, symbolized by r (as in “relationship”). The closer to 1 it is, the stronger the correlation
Natural Correlations
The correlations observed in the world around us
Third-Variable Correlation
Two variables are correlated only because each is casually related to a third variable. The possibility of a third variable can never be eliminated
Matched Samples Technique
A technique whereby the participants in two groups are identical in terms of a third variable
Matched Pairs Technique
A technique whereby each participant is identical to one other participant in terms of a third variable
Third-Variable Problem
A causal relationship between two variables cannot be inferred from the naturally occurring correlation between them because of the ever-present possibility of a third-variable correlation.
Experiment
A technique for establishing the causal relationship between variables
Manipulation
Changing a variable in order to determine its causal power
Three main steps in doing an experiment
- Perform a manipulation (called a variable)
- Measure another variable
- We see whether our manipulation of the third variable produced changes in the dependent variable
Independent variable
The variable that is manipulated in an experiment
Experimental Group
The group of people who are exposed to a particular manipulation, as compared to the control group, in an experiment
Control Group
The group of people who are not exposed to the particular manipulation, as compared to the experimental group, in an experiment
Dependent Variable
The variable that is measured in a study
Self-selection
The problem that occurs when anything about a person determines whether he or she will be included in the experimental or control group
Random Assignment
A procedure that lets chance assign people to the experimental group or the control group
Statistically Significant
p < .05, or 5% that the result would’ve occurred because random assignment had failed
Internal Validity
An attribute of an experiment that allows it to establish causal relationships
External Validity
An attribute of an experiment in which variables have been defined in a normal, typical, or realistic way (it isn’t necessary!)
Population
A complete collection of participants who might possibly be measured
Sample
A partial collection of people drawn from a population
0 < n < N when n = sample and N = population
Case Method
A procedure for gathering scientific information by studying a single individual
Random Sampling
A technique for choosing participants that ensures that every member of a population has an equal chance of being included in the sample
Why is nonrandom sampling a nonfatal flaw?
- Sometimes the similarity of a sample and a population doesn’t matter (ex: 1 pig flew, proves that one did, and that’s all that matters)
- Psychologists perform new experiments that use the same procedures but on different samples. If results match, can be more confident that the results describe basic human tendency, but if they don’t, we learn something about the influence of culture, age, etc
- The similarity of the sample and the population is simply a reasonable starting assumption. (If a medicine was tested on mice and the mice died, even though we don’t have whiskers and fur, most of us would not take the medicine)
Sir Francis Bacon
Developed the scientific method in book called Novum Orangum
Critical Thinking
Asking ourselves tough questions about whether we have interpreted the evidence in an unbiased way, and whether the evidence tells us the entire truth
We consider what we see and ignore what we don’t
Series of three letter words like SYX, GTR, BCG, etc
Within about 34 words, participants could identify that the “special” words contained a T
They never figured out that the the “special” words didn’t contain a T
Nuremberg Code of 1947 and Declaration of Helsinki in 1964
After WWII, the international community developed Nuremberg Code, then the Declaration of Helsinki, that spelled out the rules of ethical treatment of human subjects
What are psychologists expected to do when they report the results of their research?
- Write reports of their studies and publish them in scientific journals. Report truthfully on what they did and what they found. Can’t fabricate results, change records, or mislead by omission
- Obligated to share credit fairly
- Obligated to share their data with other competent professionals who seek to verify the substantive claims through reanalysis
