Psychology as a Science
Wednesday September 14th, 2022
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Is it a science?
 Depends on what school you go to
o Waterloo – Science or Art
o Laurier – Art
What is a science?
1. The universe operates according at certain natural laws (things happen in an orderly way)
2. These laws are discoverable and testable (we can use the laws to make predictions and
experiment)
The scientific method:
 Deductive reasoning – Start with big general ideas and then apply those ideas to specific
situations (p.34)
o Theory, prediction, observation
 Inductive reasoning – Using specific observation to form a general conclusion, start small
and build up to a big understanding. (p.35)
o Observation, prediction, theory
*It is not like a typical science that has the observable physical reality. You can’t test emotions
with a microscope. (p.38)
Pseudo psychology: Not based on the scientific method, appearance of science, claims to
answers all of life’s major questions. (p.40)
Hypothetico-deductive reasoning:
Scientists begin with a hypothesis (educated guess), make an observation (after doing
experiments), create a theory (based on proving hypothesis) based on your research.
1. Identify the question of interest
a. Researchers have to pay to publish
b. See what gaps there are, find the subjects of interest
2. Develop a hypothesis
a. Hypothesis testing – Test a statement
b. Null hypothesis – We have a sample, access performance (group 1 gets coffee, group 2
gets water), no impact on both groups
c. *Alternative hypothesis – There is a difference between the two groups
d. Variables (see below)
3. Select a research method, audience (participants), collect data
a. Population is a large group, specific (whole class of PSYCH at SJ2), it is hard to get
access to an entire population
b. For general knowledge, choose a sample (the first row of the class)
c. Must choose a random group – random selection
d. Case study: Focuses on a single person (p.44)
e. Naturalistic observation: Studying someone without getting involved, subject to
researchers’ bias, also odd to have a camera or observer in your home. The subject
Psychology as a Science
Wednesday September 14th, 2022
f.
g.
h.
i.
could improve or change simply because they are being watched – Hawthorne effect
(p.44-45)
Survey: Answers with a questionnaire or interview (p.46)
Experiment: Controlled observation, being able to see the effect on the dependant
variable.
Random assignment: Make sure the groups in question are even and results are not
influenced by outside factors (p.48)
Double-blind procedure: When the researcher and the participant do not know the
procedure that the participant receives. Helps keep the researcher from observing their
hypothesis (p.49)
4. Analyze the data, accept/reject hypothesis
5. Get a scientific review, publish
6. Build a theory
Variables:
Any characteristic, number, or quantity that can be measured or counted. It is the condition,
event or situation being studied.
Quantitative
Qualitative
 Naturally have numbers assigned
 Numbers are not naturally assigned
 They vary in the amount or degree but in
 They vary in kind but not in degree or
kind
amount
 Age, height, distance, heart rate,
 Model of car, ice cream flavour, colour,
temperature
political affiliation
Independent variable (IV)
Dependent variable (DV)
You can manipulate the variable
The variable that you measure (or it is
changed by the independent variable)
Operationalizing variables: Be clear, explicit, explain, define, elaborate, specific (write a
paragraph, not a sentence)
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Psychology as a Science
Wednesday September 14th, 2022
Descriptive: No control over variables, good for early ideas
 Watch people in a grocery store to see who shoplifts
 Researcher bias: Follow someone because they are black
 Participant bias: People not sharing answers because they do not like the topic
Experimental: Ethical concerns, control over variables
 How the independent variable changes the dependant variable
 There will always be bias because we are people
Example: Test on happiness
 Controlled group
o Measure happiness
o Change nothing
o Measure again
 Experimental group
o Measure happiness
o Give dogs
o Measure again
Descriptive statistics: Describe data from samples
Mean: The average of the numbers
Median: The middle number of a sequence, used the most
Mode: The number that occurs most often
Changes based on population; the median is best to use.
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Psychology as a Science
Wednesday September 14th, 2022
Frequency distributions: Get results, plot results, can be positive/negative.
Standard deviation: The approximate average deviation around the mean (not the most exact).
Inferential statistics: Possibility of prediction (inferences) from data, generalizations
Scatter diagram (scatter plot): Visual depiction of a relationship between two variables,
bivariate (2 variables) distribution, individual scores on both X and Y, used to help us describe
and interpret results.
Types of linear relationships:
Positive correlation (pandemic and dog adoptions), negative correlation (less sleep and longer
reaction time), no correlation (Internet usage and IQ)
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Psychology as a Science
Wednesday September 14th, 2022
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Run stats on this, input the data to find r. The higher number wins, positive/negative doesn’t
matter.
The coefficient of determination:
 More precise way of interpreting the meaning of the correlation
 Tells us the percentage of variance in one variable that is accounted for by the variance in the
other variable
 If the correlation between IQ scores and job performance is 0.8 then r2 = 0.64
 Run it through a program
Using correlations:
Help us understand how the value of one variable change when the value of another variable
changes, we can make predictions.
*Correlation is not causation. You can find two items that seem to be related, but there is most
likely a common factor between the two. For example: The sale of ice cream and forest fires are
not directly related, but when the temperature is hotter, you will have more ice cream sales and
more forest fires.
Assessing difference:
Our assumption of significance is not usually correct. You must set this before you do a study.
You must predict your margin of error. This will tell you if your answers are accurate or if they
were affected by an outside source.
People with/without dogs: Collect stats, compare average happiness score for people that got
dogs and those that didn’t. The stats will tell us if the dogs made a difference. The P-value
describes how likely it is it was your variable that caused the change in results. If value is less
than 0.05 is significate. It means the same result didn’t occur much (5% out of 100) and that the
results were caused by a variable and not just random. (p.54)
Protect human participants:
 Informed consent: When as many details as possible are provided to the participants so they
can make an informed decision about their participation (p.57)
 Protect participants from harm and discomfort, avoid situations that could cause harm (p.57)
Psychology as a Science
Wednesday September 14th, 2022
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Protect confidentiality, have a plan in place (p.57)
Make participation voluntary, make it clear that you do not have to partake (p.57)
Do not use deception or incomplete disclosure, open about methods and purpose (p.57)
Provide complete debriefing, do not give full knowledge beforehand because it could affect
study, talk more at the end of the study (p.58)
Research ethics boards: A study have form one with inside/outside members of the
experiment (p.56)
Using animals: Assure there are no inhuman practices
 The use of animals is only acceptable if the research will contribute to human understanding
(p.58)
 Only used if an alternative to animals was not an option (p.58)
 Use the most humane methods and smallest number necessary (p.58)
 Limit pain and stress, give recovery periods (p.58)
*You should repeat testing to assure that the hypothesis is true, and you achieve the same results
multiple times. (p.55)