Psychology 201W: Introduction to Research Methods
Hypotheses, The Scientific Method & Variables
- Labs start this week
- Office hours: RCB 6242 – Tues (3:30 pm – 4:20 pm) Thurs (11:30 am – 12:20 pm).
Review on Last Week’s Lecture:
The Scientific Method
- The Scientific Approach is based on a position of skepticism and we generally use
empirical methods to observe various phenomenon and you apply that to
Goals of Science:
- Describing behaviour.
- Predicting behaviour.
- Controlling behaviour.
- Determining causes of behaviour.
- Explaining behaviour.
1) Establish temporal precedence.
2) Covariation of cause and effect.
3) Eliminate alternative explanation.
Basic vs. Applied Research:
- Basic Research (Pure Research) is set up to answer general questions for general
- Applied Research (Implied) is set up to answer practical questions and apply some
kind of program evaluation. To apply to a specific situation.
Hypothesis Generation (Simple):
- What is the effect of X on Y?
- The relationship between two variables.
- Statement between two variables.
- When generating hypotheses, it is useful to identify the variables first and then
determine if increases or decreases of one of those variables has some kind of effect
on the other variable.
Simple Hypotheses vs. Complex Hypotheses:
Hypothesis: A statement or a claim about how variables relate to one another. PSYCH 201W
Simple Hypothesis: A statement or claim about the relationship of two variables.
- What effect does variable X have on variable Y?
- X = Independent Variable (IV).
- Y = Dependent Variable (DV).
Complex Hypothesis: Making a statement or claim about two variables that depend
on the influence of another variable
- Adding another variable into the mix.
- A statement or claim about the relationship of more than two variables.
- “The effect of X on Y depends on Z.” OR “Increases in X result in increases in Y
when Z is large, but not when Z is small.”
- Just looking at the relationship between two variables and suggesting to make that
relationship depends on something else that changes with this other variable.
- Question: “What effect does violent TV programming have on children’s
Increases of X results in increases of Y.
Simple Hypothesis: “Increases in exposure to violent TV programming
results in increases in children’s aggressive behaviour.”
- Question: “What factor influences how much of X affects Y?”
Increases in exposure to violent TV programming results in increases in
children’s aggressive behaviour.
“What factor influences how much of X (exposure to violent TV
programming) affects Y (aggressive behaviour).
Factors: Parental Supervision, Type of Programming, Family
Environment (Hostile Environment), “Amount of Exposure” (Original),
Family Socio-Economic Status (SES) and etc.
Complex Hypothesis: “Does the effect of exposure to violent TV
programming on children’s aggressive behaviour depend on family socio-
economic status (SES)?”
- Question: “Does the effect of Ritalin on goal-directed behaviour depend upon age?”
Depends on age – difference between younger people compared to older
We simulate a hypothesis in a way that it yields a specific prediction.
- You want to come up with a research question that leads to a hypothesis (a
statement of the relationship between variables).
- The hypothesis needs to be stated in a way that yields a specific prediction.
- Example: “Increases in X lead to decreases in Y”, whatever the variables you plug
into that sentence. PSYCH 201W
- That prediction that you make has to be testable.
Research Project - To be discussed further in Labs:
- Identify a topic of interest.
- Then, come up with a question on that topic.
- Develop a hypothesis that in a way yields to a specific prediction that can be tested.
- Start to come up with some design, a way to test your hypothesis.
- Design an experiment to test the hypothesis.
- Run the experiment, gather some data/information.
- Use the data to provide results, which will then be interpreted and examined to see
if they support the hypothesis.
Once the results have been determined to support our hypothesis – do we say the
hypothesis is proved?
If we have results that have been determined to be against our hypothesis – do we
say the hypothesis is disproved?
Don’t use the words “Proved” and “Disproved”!
- Going to be revisited later on in the course.
All we can do is find support or evidence that supports our claim.
- The more times we run an experiment and the more support we get for our
hypothesis = A growing level of confidence that our claim is true.
- Think of psychology as a discipline based on a series of claims – not facts.
- Find the best evidence/the best support we can on these claims, in order to
eliminate any other alternative explanations.
The Scientific Method Revisited:
Science: A method of inquiry that generates knowledge about the world through the
development of testable hypotheses that are evaluated by objective observation.
- A method, not an institution.
1) Develop a precise, objective, and valid measure of the phenomenon,
Phenomenon: Any kind of psychological entity that you are interested in.
- E.g. Anxiety, Depression, Intelligence or any kind of psychological entity.
Important Word to consider: “Dimension” PSYCH 201W
2) Examine the causes of the phenomenon, by varying the presence or absence of
the potential causes and assessing the impact on the phenomenon.
How to examine the cause of Psychological Phenomenon?
- Engage in experimentation.
- Vary the presence and absence of potential causes
- Manipulate the magnitude of cause to see what kind of effect that these variables
have on another variable.
- Assess the impact on whatever the phenomenon is.
1) “Clever Hans” – Dr. Pfungst
- A clever horse that can figure out solutions to mathematical problems.
- The horse would answer mathematical questions when asked by tapping its hoof.
- Formulated the hypothesis: “The presence of unintentional cues led to greater
accuracy in responding to the questions”.
The Presence of Unintentional Cues:
- Experiment: Vary the presence of unintentional cues.
Example of Unintentional Cues:
- The horse might be looking at the people who are observing him.
- Maybe there is a cue that is telling the horse to stop tapping its hoof.
Dr. Pfungst varied the complexity of the questions, so that the person asking
wouldn’t always know the solution.
- For the simpler questions it was easier for someone to know the solutions.
- Results: He found that when people knew the answer to the question they would
start to look towards the horse as it approached the correct answer and all the horse
did was wait until someone would look up at it and it would stop tapping its hoof.
2) “Pellagra” – Dr. Goldberger
- Pellagra = A disease of vitamin B3 deficiency, results in various skin infections.
- Number of deaths being reported due to Pellagra.
- First was considered to be an infectious disease due to various microbes being
passed by bodily fluids and also due to poor sewage control.
Dr. Goldberger thought otherwise and that it was probably caused by something to
do with diet.
- Believed that Pellagra was caused by a diet that was high in carbohydrates and low
- What actually was happening was a vitamin b3 deficiency. PSYCH 201W
He tested two hypotheses:
1) Hypothesis One: Based on the old belief that “greater consumptio