Experiment&Design Flashcards
What’s Independent variable?
Variable that is changed or manipulated
What’s Dependent variable?
Variable that is measured
Control
IV absent
Operationalise
IV-knowing precisely how it was manipulated.
DV- being confident that any variation is measured accurately.
Independent measures design
Separate group of participants used for each conditions
Strengths of independent measures design
+No order effects-different parts used for each condition.
+No demand characteristics-parts experience experimental task once.
Weakness of independent measures design
- Individual differences could distort results if parts in one condition differ from those in another.
- More parts needed-hard to find.
What is single blind procedure?
Ensures parts are unaware of the condition they’re in.
+reduces demand characteristics & controls researcher effects.
What’s researcher effect?
Negative influences researchers can have on a study by their presence or belief
What’s double blind procedure?
Ensures both experimenter and parts are unaware of the condition they’re in.
+protects against demand characteristics & researcher bias.
Repeated measures design
Same group of parts in each conditions
Strengths of repeated measures design
+unlikely to bias findings as individuals differences will affect performances in both conditions.
+uses fewer parts.
+Counterbalancing can reduce order effects.
Weakness of repeated measures design
- Order effects such as practice and fatigue can distort results.
- Demand characteristic parts see experimental task more than once.
What’s participant variable?
Individual differences between parts (eg; Age,skills,personality) that can effect their responses
What’s practice effect ?
When Parts experience experimental task more than once,they become more familiar with the task and recall previous answers.
What’s fatigue effect?
Parts becoming bored or tired-performance declines
What’s counterbalancing?
Half parts to condition A then B & other half do condition B then A.
+overcome order effects
What’s matched pairs design
Different groups of parts used in each conditions.
Each part is match on, eg; Age,gender, intelligence etc..
Strengths of matched parts design
+No demand characteristic-only see task once.
+Controls for individual differences(eg; identical twins)
+no order effects
Weaknesses of matched parts design
-Matching process is time consuming&difficult.
Lab experiment?
Conducted is artificial environment measuring the effect of the IV on the DV while controlling extraneous variables.
Strengths of lab experiment
+cause and effect relationship can be inferred.
+standardised procedures allows for easy replication-findings reliable.
Weakness of lab experiment
- Artificial situation make parts behaviour unrepresentative.
- demand characteristics
Field experiment?
Measuring the effect of the IV on the DV in natural settings on parts.
Strengths of field exp
+Natural situation-parts behaviour representative.
+No demand characteristics- parts unaware they’re in a study.
Weaknesses of field exp
- Hard to control extraneous variables so harder to replicate therefore less reliable.
- Cannot be sure there’s a causal relationship.
- ethical issues-parts unaware they’re in a study.
Quasi experiment?
Makes use of an existing change in situations to create conditions.
IV is naturally occurring
Strengths of quasi exp
+used to study real world issue.
+Natural environment-behaviour representative.
+No demand characteristics
+Enables variables that cannot practically or ethically be manipulated to be investigated.
Weaknesses of quasi exp
- Only used when naturally occurring differences arise.
- Difficult to control extraneous variables.
- Causal relationship cannot be established- no manipulation on the IV.
- Hard to replicate.
