Section 2: Scientific Processes Flashcards
What distinguishes experimental methods from the other methods?
All experiments have: IV, DV, cause and effect relationship. The aim is to establish the cause and effect relationships between the IV and the DV.
Independent Variable
The variable in an experiment which is manipulated by the researcher. This is done to see if it has any effect on the DV.
Dependant variable
The variable in an experiment which is observed/measured by the researcher. This is done to see if it has been affected by the changes made to the IV
Extraneous variable
Any variable other than the IV that might have an effect on the DV if it is not controlled. As part of designing any study, researchers should try to identify all possible EVs and attempt to control them.
4 types of extraneous variables
Participant variables
Investigator effects
Environmental variables
Demand characteristics
Participant variables
any individual characteristics or traits of the participants (other than the IV) that might affect the DV and unfairly influence the results.
Examples of participant variables
age, gender, personality, mood, intelligence
Investigator effects
Any cues or behaviour from the investigator (other than the IV) that may encourage certain behaviours in the participant, and which may allow the researcher’s expectations to unfairly influence the results, causing inaccurate results.
examples of investigator effects
words used/instructions given
tone of voice
body language
individual/physical characteristics (age/gender)
environment variables
any aspect of the research environment or situation (other than the IV) that might unfairly influence the results.
examples of environmental variables
noise, lighting, temperature, weather, time of day
demand characteristics
any cues that reveal the aims of the study to the participants. if participants become aware that they are being studied, these cues may help them to work out the aim of the study and cause them to change their behaviour, giving inaccurate results
negative effects of demand characteristic
‘please you effect’ : may try to please the researcher by giving them the result they want
‘screw you effect’ : may try to ‘ruin’ the experiment and the results
may be more self conscious if they know they are being tested/observed
- results wont reflect natural behaviour: low internal validity
examples of demand characteristics
participants working out/guessing the aim of the study due to cues given
leaving questions that reveal the aim of the experiment
2 key ways of controlling variables to ensure accurate results
standardisation
randomisation
standardisation
standardising research means putting in place controls to ensure every aspect of the research is the same for all participants and meets a consistent standard.
includes a standardised environment, standardised procedures, and standardised instructions.
how to standardise environment
using a laboratory to ensure every aspect of the environment is controlled
how to standardise procedures
using the same research methods
using the same timings
using the same materials
how to standardise instructions
read from a script or prerecord the instructions (same for all)
use the same researcher to give instructions
randomisation
ensuring all research choices are randomly selected by chance (eg using a random number generator) rather than being determined by the researcher. This is done to avoid researcher bias.
examples of randomisation
using a random name/number generator
random allocation of participants to different conditions
putting task sequences together randomly (eg a list of words) instead of the researcher putting them in a chosen order
how to control participant variables
- randomisation: random allocation of participants to different conditions
- experimental design: change to a repeated measures or matched pairs design if appropriate
how to control investigator effects
standardisation: give the same instructions to all participants (scripted/prerecorded), use the same researcher for all participants
randomisation: random allocation of participants to conditions to avoid researcher bias
single or double blind trial to avoid researcher bias
how to control environmental variables
standardisation: standardised environment (eg using a laboratory to control all environmental variables)