Experimetnal Design And Observation Methods Flashcards
What are the disadvantages of a between subject design?
- They can require large number of participants as each condition has to have different participants.
- Participant characteristics/variables (individual differences can affect the dependent variable) : Gender, age, personality, IQ, Family background, level of education, etc.
What is a confounding variable?
Extraneous variable that influences the results of the study.
Give examples of situational confounding variables
Environment
Room temperature
Time of day
How do we get rid of confounding variables ?
Constancy in conditions and standardisation.
What are expectancy effects?
How do we prevent it?
- Participants expecting what the outcome of their behaviour will be based on the condition there in.
- Placebos so conditions are constant.
How do we get rid of participant characteristics and variables such as having a hangover or gender?
-Balancing/matching Participant characteristics
What are the three main between subjects design?
- Random allocation design
- Matched group design
- Natural groups design
What is the random allocation between subjects design?
Participants randomly assigned to conditions (groups)
- this controls for participant variables as it reduces chance of a biased sample
- A big sample size is needed to reduce chance of participant variables
What is matched group design?
- Matching Participants in each group based on a certain characteristic
- Best to match Participants on the DV
- If you cant match participants on DV, match them on other variables that can affect DV
What is the disadvantage of within subject design disadvantages?
Repeatedly measures the same people on the same DV:
- Boredom/ fatigue
- Practice (order) effects : taking part in one condition influences behaviour in other conditions such as learning, fatigue form task, Habituation, sensitisation, contrast, adaptation
How do we get rid of practice effects?
Overcome by counterbalancing
What is counterbalancing?
-splinting your within subjects design into two groups and making them take part in different conditions in different chronological order.
What is an incomplete within subjects design?
- Each condition administered to each participants once.
- order of administration varied across participants.
- practice effects balanced across individuals.
- 2 main counter-balancing methods :
- all possible orders
- selected orders
How do you calculate the number of all possible orders when counterbalancing when using an incomplete within subjects design?
Multiplying all levels of IV by all numbers below it.
Minimum 3 levels of IV
How do we calculate a selected orders design when using incomplete within subjects design?
Each condition occurs once or the same number of times by each group of participants but all in different orders.
-each condition precedes and follows each other condition only once.
Describe a complete within subjects design?
Each condition administered several times-different order each time.
Practice effects balanced for each participant.
- 2 main counter balancing methods:
- block randomisation
- The ABBA design
What is block randomisation?
A block consists of all conditions
Participants complete the conditions several times, each time in a different order:
Every Participant does all possible orders.
What is the ABBA design?
- if we can only present conditions a few times and few levels of IV
- present the opposite sequence
- each condition has the same amount of practice effects.
What are limitations of the within subjects design?
Individual differences cannot testers
Time consuming as participants need to take part in all conditions
Levels of the IV represent an unfolding time sequence that cant be undone.
If the task (DV) cant be repeated this design cant be used.
Differential transfers between conditions may cause problems.
What is differential transfer?
Effects of one condition affect performance in subsequent conditions.
How to prevent differential transfer from occurring?
use a between subjects design or within-subjects design with each condition sufficiently spaced.
What are observational methods?
Study of animals and people within a natural environment
When there are practical or moral considerations mean no control of variables
What is observation without intervention?
Naturalistic observation
Behaviour as it occurs naturally without intervention
Passive recorder of behaviour
Not just out in nature
What are advantages of observation without intervention studies?
A.K.A - naturalistic
- insight into how behaviour in the real world occurs:
- high external validity
- can allow experimenting on complex social situations that cant be controlled in a laboratory environment
- developing theories
