Chapter 2: Methods Flashcards
Dogmatism
People’s tendency to cling to their beliefs and assumptions
Empiricism
Belief that accurate knowledge can be acquired through observation; Backbone of the scientific method
Scientific Method
A procedure for using empirical evidence to establish facts
Theories
Hypothetical explanations of natural phenomena
Hypothesis
A falsifiable prediction made by a theory
Why are hypotheses falsifiable?
Observations we make can prove hypotheses wrong. There are certain theories that we cannot test using the scientific method, thus we cannot evaluate its veracity (doesn’t mean it’s wrong).
Theories can never be proved right. Why?
Observations that are consistent with out theory can increase our confidence that it is right, however we can never be absolutely sure that it is because future observations may prove it wrong.
Empirical method
Set of rules and techniques for observation
3 qualities that make human beings difficult to study
We are highly complex, variable, and reactive
Limitations of everyday observations
Incomplete and inconsistent
Two steps in the measurement of a property
- Define the property- generate an operational definition with construct validity
- Detect the property- design an instrument with reliability and power
Operational definition
A description of a property in measurable terms
Construct validity
Extent to which operational definition adequately characterises the property
What makes a good detector?
- Power- ability to detect the presence of differences/changes in the property’s magnitude
- Reliability- ability to detect the absence of differences/changes in property’s magnitude
Demand characteristics
Aspects of an observational setting that cause people to behave as they think someone else wants or expects
Naturalistic observation
Technique for gathering scientific information by unobtrusively observing people in their natural environments
Techniques for avoiding demand characteristics
Privacy and anonymity, measuring behaviour that is not under a person’s voluntary control, unawareness of the true purpose of the observation
Expectations can influence…
Observations and reality
Observer bias
Tendency for observers’ expectations to influence both what they believe they observed and what they actually observed
Double-blind study
Technique to avoid observer bias; a study in which neither the researcher nor the participant knows how the participants are expected to behave
Population vs. Sample
A complete collection of people vs. A partial collection of people/animals/things drawn from a population
2 techniques for making sense out of big spreadsheets
Graphic representations and descriptive statistics
Frequency distribution
Graphic representation showing the number of times in which the measurement of a property takes on each of its possible values
Negatively skewed vs. Positively skewed distribution
Leans to the right vs. Leans to the left
Normal distribution
Mathematically defined distribution in which the frequency of measurements is highest in the middle and decreases symmetrically in both directions i.e. a bell curve or Gaussian distribution
Descriptive statistics
Brief summary statements that capture the essential information from a frequency distribution
2 most common kinds of descriptive statistics
Those that describe the central tendency of a frequency distribution and those that describe the variability
Descriptions of central tendency vs. Descriptions of variability
Statements about the value of measurements that tend to lie near the centre or midpoint of the frequency distribution vs. About the extent to which measurements differ from each other
3 most common descriptions of central tendency
Mode (value of most frequently observed measurement), mean (average value of all measurements), median (value in the middle)
Measure of central tendency in a normal distribution
Mean, mode, and median all have the same value
Measures of variability
Range (value of largest measurement in frequency distribution minus value of the smallest; can be distorted by extreme values) and Standard deviation (statistic that describes how each of the measurements differs from the mean)
Variables
Properties that can take on different values
Correlation
Occurs when variations in the value of one variable are synchronised with variations in the value of the other variable; allows us to make educated guesses about measurements
Estimations of the accuracy of predictions from a correlation
Measuring correlation’s direction and strength
Positive correlation
More is more
Negative correlation
More is less
Correlation coefficient (r)
Mathematical measure of both the direction and strength of a correlation; has a limited range
Perfect positive correlation
Every time the value of a variable increases by a certain amount, the value of a second variable also increases by a certain amount; r=1
Perfect negative correlation
Every time the value of a variable increases by a certain amount, the value of a second variable decreases by a certain amount; r=-1
No correlation
Every time the value of a variable increases by a certain amount, the value of a second variable neither increases nor decreases systematically; r=0
Exceptions to the rule of perfect positive correlation
The farther the dot is from the diagonal line, the greater an exception it is. The more data points farther from the line, the weaker the positive correlation is (r is closer to 0 than 1).
Natural correlations
Correlations we observe in the world around us; tells us the relationship between two variable but not why that relationship exists
Third-variable problem
The fact that the natural correlation between two variables cannot be taken as evidence of a causal relationship between them because a third variable might be causing them both
Experimentation
Technique for establishing the causal relationship between variables; eliminates two of the three possible causes
Manipulation
Technique for determining the causal power of a variable by actively changing its value; manipulate one variable (different conditions) and measure the other
Three steps of experimentation
- Manipulate the independent variable, which creates at least 2 conditions
- Measure the dependent variable
- Compare the value of the variable in different conditions. If they differ on average, changes to the value of the independent variable caused changes to the value of the dependent variable.
Self-selection
A problem that occurs when anything about a participant determines the participant’s condition
Random assignment
Procedure that assigns participants to a condition by chance; ensures that participants in the each condition are equal, on average, in terms of all possible third variables
How can you tell if random assignment has failed?
Calculating the odds that it has failed through statistical testing; psychologists do not accept the experiment results unless the probability (p) that the it would have been observed if random assignment had failed is less than 5% (p<0.05)
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 operationally defined in a normal typical or realistic way (representative of the real world)
Case method
Procedure of gathering scientific information by studying a single individual
Random sampling
A technique for selecting participants that ensures that every member of a population has equal chance of being included in the sample
Replication
An experiment that uses the same procedures as a previous experiment but with a new sample from the same population
Type 1 error
When researchers conclude that there is a relationship between two variables when in fact there is not (false positive)
Type II error
When researchers conclude that there is not a relationship between two variables when there is (false negative)
First rule of critical thinking
Doubt your own conclusions
Second rule of critical thinking
Consider what you don’t see
Core principles of research involving human participant
Research should: show respect for persons, show concern for welfare, and be just.
Important rules that govern the conduct of psychological research
Informed consent, freedom from coercion, protection from harm, risk-benefit analysis, deception, debriefing, confidentiality
Informed consent vs. Debriefing
Verbal agreement to participate in a study made by an adult who has been informed of all risks that participation may entail vs. Verbal description of the true nature and purpose of a study (if participant is deceived)
3 Rs tenet on the ethical use of animals in science
Replacement- justified use of animals and proof that there is no alternative; Reduction- smallest number of animals possible; Refinement- minimise discomfort, infection, illness, and pain
