The history of modern psychology
- Great thinkers in history (Aristotle, Zoroaster) raised “psychological” questions, but they answered them with anecdotes instead of evidence.
- Phrenology, the pseudoscientific belief that bumps on the skull could tell us about a person’s personality traits, became popular in the 1800s.
- Example of anecdotal “psychology” not working.
- In 1879, Wilhelm Wundt established the first psychological lab.
- Volunteers were trained to carefully observe and analyze their own sensations.
- Wundt is credited for initiating the movement to make psychology a science.
- Functionalism emphasized the purpose of behavior, as opposed to its description.
- Ask how an action helps a person/animal adapt to the environment.
- Freud was a physician who became convinced that depression, nervousness, etc came from childhood conflicts and traumas that were too threatening to be remembered consciously.
- For example, sexual feelings for a parent.
- Eventually his ideas evolved into a broad theory of personality and a method of psychotherapy, both known as psychoanalysis.
- Freud did not rigorously test his theories.
Major perspectives in psychology
- Chemical imbalances
Evolutionary psychology: how behavior that was useful in our evolutionary past may be reflected in our present behaviors, mental processes, and traits.
- How environments and experience affect humans and animals
- People learn by imitating others and by reacting to surrounding events
- Focuses on what goes on inside people’s heads
- Focuses on social and cultural forces outside the individual
- Perception of the world, expressing emotions, how we treat people
What psychologists do
- Psychotherapist: does any kind of psychotherapy. Not legally regulated.
- Psychoanalyst: practice one particular form of therapy — psychoanalysis. Requires degree and training.
- Psychiatrist: a medical doctor who treats mental disorders.
Steps for critical thinking
- Be willing to ask copious “why?” questions
- Define your terms (“What makes people happy?” “What does happy mean here?”)
- Analyze your own assumptions and biases
- Examine the available evidence (and reliability of that evidence)
- Weigh the conclusions, generating as many reasonable interpretations of evidence as possible
At the end you arrive at a theory.
Sampling participants for a study
A representative sample is more important than a large sample size.
Allow researchers to describe or predict human behavior, but not to explain it.
- Case studies
- We can’t deprive children and study the effects, but there are historical cases that can be studied.
- We often don’t know much about the circumstances, so they’re good for forming hypotheses but not testing them.
- Observational studies
- Naturalistic observation: observing people in the natural environment.
- Laboratory observation: observing people in a lab.
- More control over the environment.
- People may act differently because they’re being studied.
- Psychological tests
- It’s difficult to make tests that are reliable (producing same results repeatedly) and valid (measuring what they’re supposed to measure).
- Validity is often measured by the test’s ability to predict other independent ways of measuring the trait (criteria).
- Produce lots of data, but really difficult to ask the right questions and get well-sampled and honest data.
- Changing the phrasing of questions can change the answers.
To determine whether two or more phenomena are related (and how strongly).
Positive correlation: high values of one correlate with high values of another.
Negative correlation: high values of one correlate with low values of another.
Correlation coefficient: +1 is positive correlation, -1 is negative correlation, 0 is no correlation.
Correlation does not imply causation. Try to find other possible explanations.
- An illusory correlation is a correlation that is a coincidence.
- Independent and dependent variables
- Hold other factors constant
- Experimental group and control group should have similar people
- This can be achieved with random assignment if the sample is large
Cross-section study: comparing different age groups.
Longitudinal study: comparing the same people over time.
- Cross-section studies may conclude that old people perform badly on tests, while longitudinal studies conclude that old people perform about the same.
- Why? Because young people may be more educated or more familiar with the tests used.
Single-blind studies are where the participant doesn’t know which group they’re in.
Double-blind studies are where the participant and the researcher both don’t know.