experiments Flashcards
Define independent variable
This is the variable that changes OR is manipulated (by the researcher) to see if it has an EFFECT on the DV. (1)
Define dependent variable
This is the variable that the researcher measures. To see the effect of the IV. (1)
Define operationalising
Operationalising means to be specific and clear when defining the independent and dependent variable in an experiment, to make it easier to measure.
Why is operationalising important
If variables are vague (not operationalised then it would not be possible to repeat the research to check for consistent results.
Operationalising increases replicability/reliability as if variables are operationalised the other researchers can repeat the research in the same way to check for consistent results.
For example: For our dependent variable we may be measuring how good a participants memory is. However, memory is not fully operationalised and it would make it difficult to repeat the study.
Memory would be operationalised as: Number of words correctly recalled correctly out of 30.
Define aim
think - intends & purpose
This is a general statement of what the researcher intends to investigate, the purpose of the study.
Start with “To investigate”
Define hypothesis
This is a specific, testable statement in which the researcher predicts what will happen between the variables.
What is the difference between the aim and the hypothesis
This is a generalistatement of what the researcher intends to investigate, the purpose of the study.
Where as
This is a specific, testable statement in which the researcher predicts what will happen between the variables.
What are the 3 types of experimental hypothesis
Directional (one-tailed) - states what the difference is between the conditions
Non-directional (two-tailed) - there will be a difference between variables
Null - states there will be no difference
Define a directional hypothesis
The researcher predicts the direction that they think the results will go in.
So what difference they expect to find between the two conditions/co-variables.
Give an example of a directional hypothesis and the writing frame
There will be a significantly faster reaction time (seconds) on a hazard perception test when participants drink 75cl of Red Bull compared to participants who drink 75cl of water.
There will be significantly higher/faster/more (operationalised DV) when participants (one condition of IV) compared to when participants (other condition of the IV)
Define non-directional hypothesis
The researcher does not predict the direction that they think the results will go in.
They will just say that there will be a difference.
Give an example of a non-directional hypothesis and the writing frame
There will be a significantafference in reaction times (seconds) ona hazard perception test between participants who drink 75cl of Red Bull and participants who drink 75cl of water.
There will be a significant difference in (operationalised DV) when participants (one condition of IV) compared to when participants (other condition of the IV)
Define a null hypothesis and provide an example of a null hypothesis
An experiment also requires a null hypothesis.
This simply states that the results gained were due to chance and
not the independent variable that the researcher change manipulated.
For example
There will be NO significant difference in reaction times (seconds) on a hazard perception test between participants who drink 75cl of Red Bull and participants who drink 75cl of water.
When do you use a directional hypothesis
‘All past research has shown’
‘Previous research has shown’
When do you use a non-directional hypothesis
‘New area of research’
‘Limited previous research’
‘Previous research findings have been mixed (some research has found)’
Define extraneous variables (2)
Unwanted extra variables other than the IV (1)
that could have an effect of the DV, this would lower the internal validity of the study (1)
What are the 3 main causes of extraneous variables
Situational factors
Participant factors
Experimenter factors
Define situational factors
Things to do with the environment the research is carried out in e.g. task difficulty OR standardised instructions.
Define participant variables
Things to do with the Pts e.g. ages, gender, IQ, eye sight, hearing, personality.
TOPT TIP!! These can only be used for an independent groups design, not matched pairs or repeated measures.
Define experimenter variables
Things to do with the researcher e.g. investigator effects.
Define confounding variables
This is when an extraneous Variable is not controlled for and it DOES affect the DV and so it becomes a confounding variable.
What are the four experimental methods
Lab
Field
Natural
Quasi
Describe the lab method (2)
(2) talk about iv & dv
An experiment conducted in a lab which is a highly controlled environment, (1)
where the researcher manipulates (changes) the independent variable (IV) and measures the effect on the dependent variable (DV) (1)
Describe field method (2)
An experiment which takes place in a natural environment ( for the
ppts) such as an office or school (1) where the researcher manipulates the independent variable (IV) and measures the effect on the dependent variable (DV) (1)
Define natural method (2)
The researcher takes advantage of a naturally occurring IV (EVENT). This is a natural experiment because the variable would have changed even if the experimenter was not interested.
Note that it is the IV that is natural not necessarily the setting - participants may be tested in a lab.
Define quasi method (2)
An experiment which has an IV based on an existing individual difference between people (characteristic) (1)
which the researcher has not manipulated e.g. age or gender (1) and the researcher measures the effect on the DV.
Define demand characteristics (2)
Any clues given off within the research, this could lead to the Ppt’s change their natural behaviour choosing to either help or hinder the researcher (CONTEXT), reducing the internal.
Can be controlled by
Getting another researcher who does not know the aims of the research (CONTEXT) to carry out the experiment. Therefore, they cannot give off clues to influence the ppts.
What are the two controls for demand characteristics
Randomisation
Standardisation
Why is randomisation used
possible aspects of the research should be by random and not decided by the researcher
Which may be open to bias - this could be present an extraneous
variable
How is randomisation used
For example if Ppts have to learn a list of words in a memory experiment the order of the words should be randomly generated (e.g out of a hat/computer generated) so that the position of each word is not decided by the researcher.
When deciding the order of conditions (so which condition happens first) this should also be decided randomly (computer generated) and not by the researcher.
Why is standardisation used
So all participants experience the same environment and instructions, to avoid extraneous variables affecting measurements.
How standardisation used
Using exactly the same formalised instructions and procedures for all ppts in a research study (CONTEXT).
This includes standardised instructions that are read out to all ppts / printed and given to the ppts to read.
Define independent groups
Ppts take part in one condition only. Each condition has different group of Ppts.
How do you conduct independent group design
*A group of ppts are recruited.
*They are then split into equal sized groups.
*A different group is allocated each condition.
What are the 3 types of experimental design
Independent groups
Repeated measures
Matched pairs
Define repeated measures
All ppts take part in all conditions of the experiment.