experiments - experimental methods Flashcards
lab experiment AO1
- highly controlled environment
- researcher manipulates IV
- measures effect on DV
lab experiment - AO3
strengths
high control over extraneous variables
- artificial environment - CONTEXT
- cause and effect can be established between IV and DV
- increases internal validity
high reliability
- experiment - CONTEXT
- easily repeated in same conditions
- to check for consistent results
lab experiment - AO3
limitations
lacks ecological validity
- artificial environment - CONTEXT
- difficult to generalise findings - CONTEXT to real life
- lowers external validity
demand characteristics
- ppts may change behaviour based on clues given off by researcher - CONTEXT
- to help/hinder research
- reduces internal validity
field experiment AO1
- natural environment e.g. office/school
- researcher manipulates IV
- measures effect on DV
field experiment AO3
strengths
less prone to demand characteristics
- ppl may not know they are being watched
- less likely to guess clues given off by researcher and change their natural behaviour - CONTEXT
- increasing interval validity
high ecological validity
- real life setting - CONTEXT
- easier to generalise findings beyond setting of study to other similar settings - CONTEXT
- increasing external validity
field experiment AO3
limitations
low reliability
- natural environment CONTEXT
- hard to replicate in same conditions to check for consistent results
ethical issues
- lack of informed consent
- ppts do not know they are being watched - CONTEXT
- if they become aware they may withdraw data from research
natural experiment - AO1
- naturally occurring IV
- may still be in a lab
natural experiment AO3
strength
- high ecological validity
- often in real life setting CONTEXT
- easier to generalise findings beyond setting of the study to other similar settings CONTEXT
- increases external validity
natural experiments AO3
limitation
low control over extraneous variables
- real life setting
- cannot establish cause and effect between IV and DV
- lowers external validity
quasi experiments AO1
- IV based on existing individual difference between ppts
- researcher has not manipulated e.g. age/gender
quasi experiments AO3
strengths
SAME AS LAB OR FIELD BASED ON SCENARIO
quasi experiments AO3
limitations
sample bias
- may have suited unique characteristics
- difficult to generalise to target population CONTEXT
- decreases external validity
demand characteristics definition
- researcher gives off clues
- leads to ppts changing behaviour
- help/hinder researcher (CONTEXT)
- lowers internal validity
how to solve problem with demand characteristics
- another researcher who does not know aims of research - CONTEXT
- cannot give clues to influence ppts
problem: bias
- researcher bias
- sample bias
how to solve?
randomisation
- to avoid extraneous variables
- randomly decide order of conditions
- randomly decide list of words
- not decided by researcher
standardisation
- to avoid extraneous variables
- same standardised instructions and procedures for all ppts - CONTEXT
