RM Booklet 1: Experimental Methods Flashcards
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Steps for Behavioural Research
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1 We observe a behaviour in the world.
2 We make a theory to explain the behaviour.
3 We develop a hypothesis about the behaviour.
4 We conduct a study to test our theory.
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What is a Hypothesis?
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A prediction of what you think the result should be.
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What is Practical Application?
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When research findings are used in the real world to help people.
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independent variable
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the variable that changes or is manipulated by the researcher to see if it has an effect on the dv
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dependent variable
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the variable that the researcher measures to see the effect of the iv
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operationalising
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to be specific and clear when defining the iv and dv, to make it easier to measure (replicate)
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why is operationalising important
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vague variables -> unable to repeat experiment -> can’t check for consistent results
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tip for operationalising
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provide scale or measurement when possible
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Aim definition
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a general statement of what the researcher intends to investigate, the purpose of the study.
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Always start your aim with the words…
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To investigate
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Hypothesis definition
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A specific, testable statement in which the researcher predicts what will happen between the variables. BEFORE THE RESEARCH
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Directional hypothesis
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ONE TAILED
States what the difference is between the conditions + States the direction of the results
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Directional hypothesis uses the words…
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Faster / slower
Greater / lower
Higher / lower
Better / worse
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Non-Directional hypothesis
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TWO TAILED
States there will be a difference between the conditions but no direction
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Null hypothesis
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There will be NO difference between the conditions
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Writing frame for directional and non-directional hypothesis
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There will be significantly higher / lower / difference (operationalised DV) when participants (1st condition of the IV) compared to when participants (2nd condition of the IV).
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Why directional
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Because all previous research has shown and stated the direction the results will follow.
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Why non-directional
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Because there is no previous research to predict the direction of the results.
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extraneous variables definition
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unwanted extra variables other than the IV that will have an effect on the DY and lower in the internal validity of the study
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3 main causes of extraneous variables
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situational factors, participant variables, experimenter variables
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situational factors definition
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things to do with the environment the research is carried out in (task difficulty, standardised instructions, temperature, time given)
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participant variables definition
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things to do with the ppts (age, gender, IQ, eyesight, hearing, personality - introvert / extrovert, demand characteristics)
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experimenter variables definition
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things to do with the researcher (investigator effects, change in between groups, tone of voice, gender)
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confounding variables definition
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when an extraneous variable is not controlled for and does affect the DV (and ruins the study)
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demand characteristics definition
any clues given off within the research that could lead to ppts changing their natural behaviour choosing to help or hinder the researcher and reducing the external validity
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2 ways to control the demand characteristics
single blind procedure and double blind procedure
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what is a single blind procedure
aims of the research are hidden from ppts -> ppts unsure of true aim -> can't show demand characteristics -> increases internal validity
(researcher changes behaviour to manipulate behaviour of ppts)
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what is a double blind procedure
aims of the research hidden from ppts + the researcher
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bias meaning
when the researcher is designing the resources / experiment or collecting results
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2 ways to control bias
randomisation and standardisation
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purpose of randomisation
where possible aspects of the research should be by chance / random and not decided by the researcher which may be open to bias (present EV)
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how randomisation is used
- all potential items are put into a hat / computer generator
- draw out as many needed for condition 1 (context - scenario)
- draw out as many needed for condition 2 (context - scenario)
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purpose of standardisation
its important that within an investigation all ppts experience the same environment + instructions to avoid EV affecting measurements
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how is standardisation used
- use exactly same formalised instructions and procedures for all ppts in the research study
- includes standardised instructions -> read out to all ppts / printed and given to ppts to read (matching elements of the task on difficulty)
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what do psychologists use methods for
to conduct their research
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what are the 2 areas of methods
experimental methods
non-experimental methods
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what are experimental methods
research methods you would use if you were conducting an experiment
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what are non-experimental methods
research methods you would use if you were not conducting an experiment
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what are the 4 types of experimental methods
lab
field
natural
quasi
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lab definition (experimental methods)
an experiment conducted in a lab which is a highly controlled environment where the researcher manipulates (changes) the IV and measures the effect on the DV
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*1st strength of a lab (EV)
high level of control over EV (light) as its carried out in a fake environment (CONTEXT) therefore cause and effect can be established between the IV and the DV which increases the interval validity of the research
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2nd strength of a lab (reliability)
high in reliability as the experiment (CONTEXT) can be easily repeated in the same conditions to check for consistent results AS IT HAS STANDARDISED PROCEDURE (CONTEXT).
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*1st limitation of a lab (ecological validity)
lacks ecological validity as its carried out in an artificial environment (CONTEXT) therefore its difficult to generalise the findings (CONTEXT) beyond the setting of the study, lowering the external validity
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2nd limitation of a lab (demand characteristics)
is prone to demand characteristics where the ppts change their natural behaviour based on clues given off by the researcher (CONTEXT) this could lead to ppts choosing to either help or hinder the researcher, reducing the internal validity
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field definition (experimental methods)
an experiment which takes place in a natural environment (for the ppts) such as an office or school where the researcher manipulates the IV and measures the effect on the DV
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1st strength of a field (demand characteristics)
less prone to demand characteristics as people might not know they are being watched so they are less likely to guess clues given off by the researcher and change their natural behaviour (CONTEXT). therefore increasing the internal validity
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*2nd strength of a field (ecological validity)
high ecological validity as its based in a real life setting and therefore its easier to generalise the findings beyond the setting of the study to other similar settings (CONTEXT) increasing the external validity
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*1st limitation of a field (reliability)
low in reliability as the environment is natural (CONTEXT) it is difficult to repeat with the exact same conditions to check for consistent results
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2nd limitation of a field (ethical issues)
this could create an ethical issue of lack of informed consent as people may not be aware they are being studied (CONTEXT) so wouldn't have given their consent. if they become aware they may become upset and wish to withdraw their data from the research
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natural definition (experimental methods)
the researcher takes advantage of a naturally occurring IV *EVENT - earthquake / adoption*. this is a natural experiment because the variable would have changed even if the experimenter was not interested
NOTE: its the IV that is natural not necessarily the setting - ppts may be tested in a lab
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*1st strength of a natural (practical or ethical reasons)
natural experiments provide opportunities for research that may not otherwise be undertaken for practical or ethical reasons. for example, Rutter's study on Romanian orphans would have been unethical to manipulate unless the institutionalisation (IV) had not occurred naturally (CONTEXT). Therefore, natural experiments contribute to a greater psychological understanding or behaviour.
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2nd strength of a natural (ecological validity)
ONLY IF NATURAL SETTING
high ecological validity as natural experiments are often based in a real life setting therefore its easier to generalise the findings beyond the setting of the study to other similar settings (CONTEXT) increasing the external validity
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*1st limitation of a natural (repetition)
naturally occurring event may only happen very rarely which limits opportunities for research (CONTEXT) this means it is unlikely that the research can be repeated to check for consistent results so lacks reliability
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2nd limitation of a natural (EV)
ONLY IF NATURAL SETTING
low control over extraneous variables as natural experiments usually take place in a natural environment (CONTEXT). therefore its difficult to establish cause and effect between the IV and the DV lowering the internal validity of the study
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quasi definition (experimental methods)
an experiment which has an IV based on an existing individual difference between people (characteristic - brain surgery, with / without disorders) which the researcher has not manipulated (age / gender) and the researcher measures the effect on the DV
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evaluation of quasi
quasi can be conducted in a natural or controlled environment (field / lab). therefore, depending on the scenario, you would have to select the appropriate evaluation (strengths / weaknesses)
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a limitation for quasi (sample bias)
sample bias as the sample being studied may have unique characteristics which may mean that it is difficult to generalise to the target population (CONTEXT) decreasing the external validity of the study
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3 types of experimental design
- independent groups design
- repeated measures design
- matched pairs design
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individual differences definition
characteristics of individual ppts (age, IQ, memory, capacity etc) that might influence the rest of the study (DV)
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order effects definition
the order in which conditions occur could cause ppts to become bored, better or fatigued by the next condition
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demand characteristics definition
ppts pick up clues about the research leading them to change their natural behaviour to help or hinder the researcher
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IGD definition
ppts take part in 1 condition only. each condition has different group of ppts.
2m for application / context to the scenario
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IGD how to conduct it
1 a group of ppts are recruited
2 they are then split into equal sized groups
3 a different group is allocated each condition
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IGD advantage (no order effects)
there will be no order effects as ppts only take part in 1 condition only so they will not get bored / fatigued / batter at the task / having lasting effects from 1 condition to the next (CONTEXT) unlike RMD where ppts take part in all conditions and could have order effects making IGD more appropriate.
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IGD disadvantage (individual differences)
individual differences may affect the DV as there are separate groups of ppts in each condition (some ppts could have a better - memory - which wouldn't be suitable in a - memory - study) (CONTEXT) lowering the internal validity unlike RM that uses the same group of individuals in all conditions to reduce the effect of individual differences.
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RMD definition
all ppts take part in all / both conditions of the experiment
2m for application / context to the scenario
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RMD how to conduct it
1 ppts complete 1 condition
2 after a sufficient time lapse (an hour) they will complete the other condition
3 the task (DV) should be different but matched on difficulty / measuring the same thing.
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RMD advantage (individual differences)
individual differences between ppts in each condition are removed (IQ as potential confounding variables, as the same ppts take part in all conditions) (CONTEXT) therefore the researcher can be more sure that any changes in the DV are due to the IV and not any other variable increasing the internal validity of the research unlike IGD that will use different ppts in different conditions so individual differences could affect the DV
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RMD disadvantage (order effects)
order effects may occur when ppts take part in more than 1 experimental condition they may perform worse in the 2nd condition (due to boredom or fatigue) or better in the 2nd condition (due to practise), or there may be lasting effects from condition 1 to condition 2 (CONTEXT) lowering the internal validity unlike IG where ppts only take part in 1 condition so cannot be susceptible to order effects.
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RMD disadvantage (increased chances of DC)
increased chances of DC as ppts take part in all conditions. they may pick up on clues given off by the researcher as they spend much more time with them, or from the research situation, and change their natural behaviour to help or hinder the researcher (CONTEXT) lowering the internal validity, unlike IGD where ppts are less likely to pick up on clues as they only take part in 1 condition of the research.
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MPD definition
ppts are matched on important characteristics in the study (age / IQ). by giving them an appropriate test and matching 2 ppts with the same / similar score. each member of the pair is then randomly allocated across each condition.
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MPD how to conduct it
1 choose a variable to match ppt on
2 test the ppt on this variable before the study
3 match ppt with the same / similar scores
4 randomly allocate each member of the pair to 1 condition
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MPD advantage (reduced individual differences)
reduces individual differences between ppts as it matches ppts on variables important to the research, such as IQ, age, happiness. (CONTEXT) therefore, the researcher can be more sure that any changes in the DV are due to the IV and not any other variable increasing the internal validity
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MPD advantage (no order effects)
there will be no order effects as ppts only take part in 1 condition so they will not get bored / fatigued or better at the task / have lasting effects from 1 condition to the next (CONTEXT) unlike RMD where ppts take part in all conditions and could have order effects
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MPD disadvantage (individual differences not fully eliminated)
individual differences cannot be fully eliminated. psychologists match ppts on variables important for the research but are not able to match ppts on all variables (CONTEXT). therefore this could question the validity of the MPD. unlike RM where each condition will use the same ppts therefore, individual differences will be eliminated
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the controls for experimental design help to do what?
increase internal validity
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2 controls for experimental design
random allocation (of the ppts) -> individual differences -> IGD
counter balancing -> order effects -> RMD
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difference between randomisation and random allocation
randomisation = TASK in research
random allocation = PPTS in research
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problem with IGD
individual differences -> different ppts used in each condition -> therefore in 1 condition ppts may have a particular trait that makes them perform better at the DV (context) -> meaning it wasn't the IV that affects the DV, lowering the internal validity
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control for individual differences (IGD)
random allocation
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why use random allocation
ensures that each ppt has the same chance of being in 1 condition as any other condition, therefore it's unlikely that all ppts in 1 condition will share a characteristic to help them perform better at the DV
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how to use random allocation
1 write the names of the ppts on equal sized pieces of paper
2 put the paper in a hat
3 then randomly pick out (ppts) names and place half in C1 and the other half in C2 (CONTEXT)
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problem with RMD
order effects -> ppts take part in all conditions and so ma perform better in C2 (due to practise) / worse in C2 (due to fatigue) / C1 may have lasting effects on C2
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control for order effects (RMD)
counterbalancing (ABBA) method
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why use counterbalancing (ABBA) method
to control and reduce order effects
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how to use counterbalancing (ABBA) method
1 half the ppts complete CA then CB (CONTEXT)
2 the other half complete CB first then CA
3 order effects are balanced / distributed across both conditions
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what is sampling all about
how a psychologist chooses ppts to be in their research
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what is a population
the group of people who are at the focus of the researcher's interest
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what is a sample
- a group of people taken from the target population to take part in the research
- assumed as representative of population
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how many sampling techniques are there
5
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name the 5 sampling techniques
- random sampling
- systematic sampling
- stratified sampling
- opportunity sampling
- volunteer sampling
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random sampling definition
every person in the target population has an equal chance of being selected
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how to do random sampling
- create a complete list of all the target population
- write names on equal size pieces of paper and put in a hat
- without looking select the number you want in your sample from the hat
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advantage: random sampling (unbiased)
potentially unbiased as everyone in the target population has an equal chance of being selected for the study (CONTEXT). this means any EV will be equally divided between the different groups. this increases the internal validity.
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disadvantage: random sampling (time consuming)
very time consuming because it takes time and can be difficult collecting all the names of ppts to take part in the study (CONTEXT) and it is not guaranteed ppts would want to take part in the research.
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systematic sampling definition
a 'system' is applied to select ppts
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how to do systematic sampling
- create a sampling frame to organise the target population (put all the people in the target population in order)
- decide on the system (every 5th or 10th person is chosen until there are enough ppts for the sample)
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advantage: systematic sampling (avoids researcher bias)
avoids researcher bias as the researcher has no influence over who is chosen to take part in the study (CONTEXT) as it is objective once the system to select ppts is established
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disadvantage: systematic sampling (not that representative)
the sample may not be representative as not everyone has an equal chance of being picked therefore it is difficult to generalise the findings to the target population (CONTEXT). moreover, creating the system and collecting names could be time consuming and difficult for the researcher.
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opportunity sampling definition
being there at that moment in time - for example waiting for ppts in the canteen during p3 and asking the first 30 ppts who walk past to participate
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how to do opportunity sampling
go somewhere where you will have access to the population you want to study and ask the first 30 ppts who are there at that moment in time if they will take part
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advantage: opportunity sampling
very quick, easy and less money is required as you choose who is available at the time for your sample, (CONTEXT) unlike random sampling which takes a long time to identify everyone in the target population and make a list of all names
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disadvantage: opportunity sampling
may not be representative of the target population, those picked by an opportunity sample are present in the same place at the same time, doing similar things, (CONTEXT) therefore they may have similar personalities (E.G.), making it difficult to generalise findings to the wider population
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volunteer sampling definition
this is a 'self selected' method where people volunteer themselves to be ppts, e.g. placing an advert for ppts then waiting for the first 30 replies.
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how to do volunteer sampling
place an advert where people in the target population will see it and wait for the first (30) people to reply
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advantage: volunteer sampling
very quick, easy and cheap to conduct as all that is required is to place an advert for the study in a place the target population may be (CONTEXT) and wait for ppts to volunteer to take part in the study (number) unlike random sampling which take time to place names into a hat and give the population an equal chance of being picked
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disadvantage: volunteer sampling
the sample maybe bias / not representative as only a certain type of personality (extrovert / curious / more likely to please the researcher) will volunteer (CONTEXT) therefore difficult to generalise to the target population
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stratified sampling definition
an advanced / more sophisticated way of sampling where the make-up of the sample reflects the proportions of certain sub-groups in the target population (if 70% of the TP are female then 70% of sample is female as well)
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how to do stratified sampling
1 identify the different sub-groups that make up a population (males / females)
2 calculate how many you would need for each proportion you would need for your sample size (if you wanted a sample of 80 ppts what would 70% of 80 be -> changes depending on scenario)
3 number of ppts which make up each proportion are chosen using random sampling (explain briefly how)
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equation used for stratified sampling if given %
(sample size wanted / 100) * % size of sub-group
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equation used for stratified sampling if not given %
(sample size wanted / TP size) * sub-group size
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advantage: stratified sampling
most representative sample as it accurately reflects the make-up of the TP (CONTEXT) in the correct proportions / amounts meaning findings can be generalised to the TP.
Stretch: however, stratified sampling is not perfect. the strata cannot reflect all the ways people are different so complete representation of the TP is not always possible.
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disadvantage: stratified sampling
very time consuming because it takes time working out the proportions of ppts needed (CONTEXT) and it is not guaranteed ppts would consent to take part.
