IB Psychology Semester 1 Midterm
Unit 1: Research methods and data interpretation
1.1 What is psychology?
The scientific study of the human mind and behavior
1.4 The experiment?
The key to determining causality in psychology
Cause-effect relationships
Internal validity
The level to which we are confident that the independent variable affected the dependent variable
Compromise when variables are not controlled
Confounding variable
Trait of participant that was not controlled
Construct validity
If the measure truly measures the theoretical construct its supposed to be
External validity
The level at which we can generalize our findings
True experiments
Begin with a hypothesis
H(hypothesis)+H₀ (null hypothesis)
Experiments never prove anything
Objective: disprove something
Null Hypothesis
The IV has no effect on the DV
All variables except for the IV and DV are controlled
Participants are randomly allocated to conditions
1 condition
Independent samples design
2 conditions
Repeated measures design
Quantitative data and can be statistically analysed
IV causes change in DV
Quasi experiments
Allocates participants according to preference
Can’t draw conclusions of causality
IV is not manipulated by the researcher
Lab vs Field experiments
Can be Quasi or True
Why is the sampling technique important?
Representative
Findings can be generalised to the rest of the population (external validity)
A good sample avoids selection bias
When participants are not representative of the larger population being studied
3 ways selection bias occurs
1: Participants self select into the study
2: Researcher intentionally or unintentionally chooses someone
3: Certain groups are excluded from the sample due to how they’re selected
Self selected samples
Response to ads, posts, or public notices
Pro: Convenient and quick
Con: Biased, low external validity
Opportunity samples
Availability
Pro: quick
Con: Biased, low external validity
Random samples:
Equal chance of being selected
Pro: High external validity, controls bias
Con: Requires full population list, not practical and time consuming
Stratified samples
Divided into subgroups based on a shared characteristic
Random selection
Pro: High external validity
Con: Complex and time consuming
Representational generalizability
Target population: Group of people that the researchers want to investigate
TP Could be:
Understand how stress affects people’s ability to make rational choices
Understand the eating habits of working-class Americans
A TP can be huge, e.g: everyone on the planet, or it can be small, e.g: one class in a school
From that TP I can then select a group to be in my research, that group is my sample
I can only generalize to the population from which my sample is drawn
If I’m studying how stress affects behavior of our IB candidates, I couldn’t say “a limitation of this study is that I can’t generalize these findings to the general public”
The general public isn’t completing the IB at our school
Sampling Issues: student samples
About 60%-80% of Western psychological research relies on university student samples
Over-reliance : criticized in the field for limiting the generalizability of findings
Often used because they’re reliable, accessible, and inexpensive
How do they differ from the general population?
Age, socioeconomic status, education level, life experience, more verbal and social
Sampling issues: WEIRD examples
Western
Educated
Industrialized
Rich
Democratic
Used to describe the populations that most psychological research is based on
To show how unrepresentative they are of the global population
Limitations of experiments
Participant biases
Any systematic way in which participants’ expectations, motivations, or behavior influence the outcome of a study independently of the variables being controlled
Demand characteristics
Clues in experiments that lead participants to guess the purpose of the study, therefore changing their behavior accordingly
Expectancy effect
Do what they want
Screw you effect
Do your worst on purpose
Reactivity
Participants alter their behavior just because they’re aware they’re being observed or measured
Ex: work harder when they know someone is watching
Placebo effect
When a person experiences a real change in symptoms or behavior because they believe they’re getting treated
Nocebo effect
Same but in a harmful way
Social desirability bias
Alter behavior to seem more favorable by others
Researcher or society
Occurs in self-reported data
Interview/survey
Carryover effects
In a repeated measures design (multiple conditions)
Effects of one condition influence performance in a later condition
Order effects
Ex: Interference, practice, and fatigue effect
Interference effect
Happens in memory research
When information from the first condition interferes with information in the second condition
Ex: trying to remember a list of words, I remember some words that were on a previous list
Practice effect
Improvement in performance because of exposure/practice
Reduced anxiety/familiarity/different strategies to improve
Fatigue effect
Decline in performance because of tiredness, boredom or lack of motivation
Perspectives in psychology
Perspective vs Bias
Perspective
Lens or viewpoint psychologists use to study and explain human behavior
Uses cognitive/sociocultural approach
Cultural perspective
Intentional approach that recognizes the influence of culture on human behavior, thinking, and emotion
Bias
An error or distortion in thinking, treats one viewpoint as “better”
Cultural bias
Unconscious preference for one culture over others, viewing it as superior
Determinism
The idea that all human thoughts, feelings, and behaviours are caused by specific factors
Internal: biology
External: environment
Biological determinism
Behavior is shaped by genetics, brain structure, neurochemistry, and hormones
Environmental determinism
Behavior is shaped by external stimuli and learning
Soft determinism
Still have control over our actions despite internal or external influence
Reductionism
Breaks behavior down into the simplest parts to understand them
Can reduce phenomenons to its basic components, whether biological, cognitive, or behavioral
Allows for scientific testing and focused interventions, but often ignores context and the complexity of the whole person
Holism
Looks at the whole person considering all the factors
Struggles to identify cause-effect relationships
Universalism
Assumes that psychological principles apply across all humans, regardless of culture/context
Relativism
Argues that behavior and mental processes are shaped by culture and therefore vary
Correlational studies
Examine relationship between 2 or more variables
Positive correlation: Both variables are affected in the same way
As x increases, y does too
Negative correlation
X decreases, y too
No cause-effect relationship can be determined
Correlation
Measurement of the extent to which pairs of related values of 2 variables tend to change together or co-vary
Curvilinear relationship
Relationship between 2 variables where as 1 variable increases, so does the other, but only up to a certain point, after which, as 1 increases, the other decreases
Unit 2: Cognition and learning
Classical conditioning
A Neutral stimulus (NS), which doesn’t lead to any natural responses, is paired with an unconditioned stimulus (UCS), which presents an unlearned, natural response.
Over time, the NS becomes conditioned
When the previous NS is presented, there is a new conditioned response
Application: aversion therapy
Treatment based on classical conditioning where an unpleasant stimulus is paired with an undesirable behavior to reduce or eliminate that behavior. Ex: phobias
Operant conditioning
Thorndike’s Law of Effect
Responses followed by satisfying consequences are more likely to be repeated, while responses followed by unpleasant consequences are less likely to be repeated
Type of learning in which behavior is shaped by its consequences, such as rewards or punishments
Fixed and variable schedules
Fixed
Reinforcement after x amount of responses or x amount of time
Variable
Expecting a reward but don’t know when you’ll get it