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Chapter 2. The Methods Of Psychology. Schacter Gilbert Wegner. PSYCHOLOGY. Slides prepared by: Melissa S. Terlecki, Cabrini College. 2.1. Empiricism: How to Know Things. PSYCHOLOGY. Schacter Gilbert Wegner. Empiricism: How to Know Things.
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Chapter 2 The Methods Of Psychology Schacter Gilbert Wegner PSYCHOLOGY • Slides prepared by: • Melissa S. Terlecki, Cabrini College
2.1 Empiricism: How to Know Things PSYCHOLOGY Schacter Gilbert Wegner
Empiricism: How to Know Things • Three things that make people especially difficult to study: • Complexity • Variability • Reactivity
Empiricism: How to Know Things Dogmatism: the tendency for people to cling to their assumptions. Empiricism: originally a Greek school of medicine that stressed the importance of observation; now generally used to describe any attempt to acquire knowledge by observing objects or events. Method: a set of rules and techniques for observation that allow researchers to avoid the illusions, mistakes, and erroneous conclusions that simple observation can produce. 4
Questions • Why is it so hard to study people scientifically?
2.2 The Science of Observation: Saying What PSYCHOLOGY Schacter Gilbert Wegner
Culture and Community: Expecting a Helping Hand? It Depends Where You Are • Observational study of helping behaviors in a naturalistic context. • Helpfulness varied between locations.
Measurement • Observe: use your senses to learn about something’s properties. • Operational definition: a description of an abstract property in terms of a concrete condition that can be measured. • Measure: a device that can detect the measurable events to which an operational definition refers. • defining and detecting. • for example, electromyograph (EMG): a device that measures muscle contractions under the surface of a person’s skin.
Questions • How could you measure happiness?
Measurement • Prerequisites for accurate measurement: • validity: the characteristic of an observation that allows one to draw accurate inferences from it. • reliability: the tendency for a measure to produce the same result whenever it is used to measure the same thing. • power: the tendency for a measure to produce different results when it is used to measure different things.
Samples • Case method: a method of gathering scientific knowledge by studying a single individual. • Population: the complete collection of participants who might possibly be measured. • sample: the partial collection of people who actually were measured in a study.
Questions • How can an exceptional case teach us about normal behavior?
Demand Characteristics • Demand characteristics: those aspects of an observational setting that cause people to behave as they think an observer wants or expects them to behave. • Naturalistic observation: a method of gathering scientific knowledge by unobtrusively observing people in their natural environments.
Questions • Why do people act differently when they know they’re being observed?
Demand Characteristics • Naturalistic observation cannot solve the problem of demand characteristics. • Some events cannot be observed naturally. • Some observations can only be gathered through direct interaction. • Private or anonymous responding, measuring behaviors not susceptible to demand, and blind procedures can minimize demand characteristics. • cover stories. • filler items.
Questions • Why is it sometimes important that participants not be aware of an experiment’s true purpose?
The Blind Observer • Expectations can influence observations. • Expectations can influence reality. • Double-blind observation: an observation whose true purpose is hidden from the researchers as well as from the participant.
Questions • When might a computer run a better experiment than a human being?
2.3 The Science of Explanation: Saying Why PSYCHOLOGY Schacter Gilbert Wegner
Correlation and Causation • Correlation: the “co-relationship” or pattern of covariation between two variables, each of which has been measured several times. • Variable: a property whose value can vary or change. • Third-variable correlation: the fact that two variables may be correlated only because they are both caused by a third variable.
Table 2.1: Hypothetical Data of the Relationship Between Happiness and Altruism (p. 41)
Questions • Televised violence and aggression are correlated. Does that mean televised violence causes aggressiveness?
Matched Samples and Matched Pairs • In order to eliminate the possibility that a third variable (and not the independent variable) caused changes in the dependent variable: • matched samples: an observational technique that involves matching the average of the participants in the experimental and control groups. • matched pairs: an observational technique that involves matching each participant in the experimental group with a specific participant in the control group.
Hot Science: Establishing Causality in the Brain • Brain damage may be related to particular patterns of behavior, but that relationship may or may not be causal. • Ethically, we cannot experiment with brain damage, but can temporarily deactivate brain regions. • Transcranial magnetic stimulation (TMS)
Matched Samples and Matched Pairs • Cannot dismiss all potential third variables. • third-variable problem: the fact that the causal relationship between two variables cannot be inferred from the correlation between them because of the ever-present possibility of third-variable correlation.
Experimentation • Experiment: a technique for establishing the causal relationship between variables, through manipulation. • independent variable: the variable that is manipulated in an experiment. • experimental group: one of the two groups of participants created by the manipulation of an independent variable in an experiment that is exposed to the stimulus being studied. • control group: one of the two groups of participants created by the manipulation of an independent variable in an experiment that is not exposed to the stimulus being studied. • dependent variable: the variable that is measured in a study.
Questions • In what ways do we perform experiments in everyday life?
Drawing Conclusions • Internal validity: the characteristic of an experiment that allows one to draw accurate inferences about the causal relationship between an independent and dependent variable. • An independent variable has been effectively manipulated. • A dependent variable has been measured in an unbiased way with a valid, powerful, and reliable measure. • A correlation has been observed between the independent and the dependent variable.
Drawing Conclusions • External validity: a characteristic of an experiment in which the independent and dependent variables are operationally defined in a normal, typical, or realistic way. • Theory: a hypothetical account of how and why a phenomena occurs, usually in the form of a statement about the causal relationship between two or more properties. • hypothesis: a specific and testable prediction that is usually derived from a theory.
Questions • Should variables be defined as they typically are in the real world?
Drawing Conclusions • Generalizing from the sample to the larger population: • 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. • Nonrandom samples are acceptable. • Sometimes generality doesn’t matter. • Sometimes generality can be determined. • Sometimes generality can be assumed.
Questions • When can a sample teach us about a population?
2.4 The Ethics of Science: Saying Please and Thank You PSYCHOLOGY Schacter Gilbert Wegner
The Ethics of Science: Saying Please and Thank You • Code of ethics (APA, 1958): • informed consent: a written agreement to participate in a study made by a person (adult) who has been informed of all the risks that participation may entail. • freedom from coercion. • protection from harm. • risk-benefit analysis. • debriefing: a verbal description of the true nature and purpose of a study that psychologists provide to people after they have participated in the study.
The Ethics of Science: Saying Please and Thank You • Institutional Review Board (IRB) approval required. • Non-human psychological research performed. • ethical treatment and rights. • costs versus benefits. • moral dilemma.
Questions • Is it ever justifiable to harm a human or nonhuman research participant?
Where Do You Stand? The Morality of Immoral Experiments • Nazi doctors during World War II unethically experimented on prisoners. • Controversial publication of data results.