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.
How is a repeated measures conducted
*Ppts complete one condition.
*After a sufficient time lapse (an hour) they will complete the other condition.
*The task (DV) should be different but matched on difficulty/measuring the same thing.
Define matched pairs
Ppts are matched on important characteritsics in the study e.g. age or IQ.
By giving them an appropriate test and matching two ppts with the same score.
Each member of the pair is then randomlv allocated across each condition
How is matched pairs conducted
- Choose a variable to match ppt on
*Test the ppt on this variable before the study - Match ppt with the same scores
- Randomly allocate each member of the pair to one condition
What is the problem with independent groups design & repeated measures design
Individual differences
Order effects
What is the problem with independent groups design
Individual differences are a possible issue when an independent groups design has been used. Because there are different ppts in each condition, therefore in one condition the pts may have a particular trait that makes them perform better at the DV (CONTEXT) - meaning it wasn’t the IV that affect the DV, lowering the internal validity.
What is the control for independent groups design
Random allocation
Why is random allocation used for independent groups design
This ensures that each Ppt has the same chance of being in one condition as any other condition, therefore it is unlikely that all ppts in one condition will share a characteristic to help them perform better at the DV.
How is random allocation done
- Write the names of the ppts on equal sized pieces of paper.
- Put the paper in a hat
- Then randomly pick out pts names an place half in condition 1 and the other half in condition 2 (CONTEXT).
What is a problem with repeated measures design
Order effects are a possible issue when a repeated measures design has been used. Ppts take part in all conditions and so may perform better in the second condition (due to practice) or worse in the second condition (due to fatigue), or the 1st condition may have lasting effects on the 2nd conition.
(CONTEXT)
What is the control for repeated measures design
Counterbalancing (ABBA) method
Why is counterbalancing (ABBA) used for repeated measures design
To control and reduce order effects
How is counterbalancing (ABBA) method done
- Half the Ppts complete condition A then condition B. (CONTEXT)
- The other half complete condition B first then condition A.
- Order effects are balanced distributed across both conditions.
Explain the difference between a population and a sample (2)
The group of people who are the focus of the researcher’s interest are called the population (or target population).
However, it wouldn’t be possible to include ALL members of the target population in a piece of research
Where as
A sample is a group of people taken from the target population to take part in the research. It is assumed that the sample is representative of the target population.
What are the five techniques that psychologists can use to obtain a sample
- Random sampling
- Systematic sampling
- Stratified sampling
- Opportunity sampling
- Volunteer sampling
What is random sampling
Every person in the target population has an equal chance of being selected.
How is random sampling done
Create a complete list of the target population
Write names on equal size pieces or paper and put in a hat
Without looking select the number you want in your sample from the hat
What is systematic sample
A ‘system’ is applied to select ppts
How is systematic sampling done
Create a sampling frame to organise the target population
e.g. put all the people in the target population in alphabetical order.
Decide on the system e.g. very 5th or 10th person is chosen until there are enough pts for the sample.
What is stratified sampling
An advanced way of sampling where the make-up of the sample reflects the proportions of certain subgroups in the target population. E.g. is 70% of the target population are female then 70% of the sample will be female as well.
How is stratified sampling done
- Identify the different sub-groups that make up a population e.g. males/females.
- Calculate how many of each proportion you would need for your sample size e.g. if you wanted a sample of 80 ppts what would 70% of 80 be.
- No. of Ppts which make up each proportion are chosen using random sampling.
How do you calculate stratified sampling if the scenario does give you a percentage
(Sample size wanted/100 x Percentage size of sub-group
How do you calculate stratified sampling if the scenario doesn’t give you percentage
(Sample size wanted / Target pop size) x Subgroup size
What is opportunity sampling
Being there at that moment in time - for example waiting for participants in the canteen during period
3 and asking the first 30 pts who walk past to participate.
How does opportunity sample work
Go somewhere we 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.
What is volunteer sampling
This is ‘self selected’ method where people volunteer themselves to be participants, E.g. placing an advert for participants then waiting for the first 30 replies.
How is volunteer sampling done
Place an advert where people in the target population will see it and wait for the first 30 people to reply.
What does reliability mean
Refers to the ability to repeat a study in similar conditions to gain consistent results
What can test re test be used to
Assess the reliability of any piece of research E.g am experiment, a questionnaire, a controlled observation
How do you do a test re-test
- Participants are given a task or measure to complete
(CONTEXT) - The same participants are then given the same task (CONTEXT) after a time delay e.g. two weeks.
- Correlate the results from each test (CONTEXT) using stats test.
- A strong positive correlation of above +0.8 shows high reliability
What are the types or internal validity
Face validity
Concurrent validity
What are the types of external validity
Population
Ecological
Temporal
What is internal validity
Is the research study measuring what it intends to measure? Is it measuring the effect of just the IV on the DV?
What is the internal validity affected by
Extraneous variables e.g. demand characteristics, researcher bias, investigator effects, social desirability, order effects
What is the external validity
Whether the findings can be generalised outside of the study
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What is ecological validity
A form of external validity. The extent to which findings can be generalised beyond the setting of the study to other real life settings.
What is population validity
A form of external validity. The extent to which findings can be generalised beyond the sample studied to the target population.
What is temporal validity
A form of external validity. The extent to which findings remain true over time and can be generalised to other time periods.
Is the internal and ecological validity high or low for the following
Lab
Field
Natural
Quasi
High, low
Low, high
Low, high
What are the ways of assessing validity
Face validity
Concurrent validity
How do you conduct face validity (3)
An independent psychologist in the same field looks at the experimental conditions (questions - if a questionnaire, behaviour categories - if an observation) (1)
to see if they look like they measure what they intend to measure (CONTEXT). (2)
If the researcher says ‘yes” then the research is said to have face validity. (3)
How do you conduct concurrent validity (3)
A way of assessing validity by comparing the results of the new testa
(CONTEXT) with the results from another similar test (1)
which has already been established for Its validity, using a stats test (2)
if results from both tests (CONTEXT) are similar then we can assume the test valid. The correlation of the two results gained from an appropriate stats test should exceed (3) 0.8
What is experimental research
Use of a control group to assess that the IV has affected the DV (establishing cause & effect).
Standardised procedures/instructions to reduce investigator effects.
The use of single blind procedures to reduce demand characteristics
& double blind procedures to reduce demand characteristics and investigator effects.
What is meant by a pilot study (2)
A pilot study is a small scale trial run of the research before the real main scale research (1)
takes place to identify any problems and AMEND them.(2)
What are the aims of a pilot study (3-4)
STQCEAI
Sometimes people tend to question or interview - catipiller slugs & bugs.
Even vegans are interested
- Check standardised procedures and general design
- Check the amount of time given to pts is enough to complete the task (LINK TO THE SCENARIO, WHAT IS THE TASK??)
- For questionnaire or interview to make sure the questions are clear
- For observations check coding systems and behaviour categories are understood, check observer/camera in a good position to see behaviours.
- Extraneous variables can be identified and possibly eliminated (LINK - GIVE AN EXAMPLE)
- Ask the ppts to discuss their experiences of the experiment
- ANY PROBLEMS CAN BE IDENTIFIED AND ADJUSTED BEFORE THE MAIN STUDY
What are the four ethical issues
DIPC
Deception
Informed consent
Protection of participants
Confidentiality
What is deception
Deception is when the ppts are not told the true AlM of thi study deliberately, to prevent participants from showing demand characteristics.
What is informed consent
Where ppts give permission to take part in the study after being informed’of the true aims of the research as well as being given the right to withdraw.
What is protection of participants
Ppts should be protected psychologically and physically. They must not be placed at more risk than they would be in everyday life.
What is confidentiality
Ensuring pts details and data (findings) remain anonymous so they cannot be identified in the research. The researche could use fake (pseudo names) names/initials e.g. Genie and patient KF
Who develops guidelines for all psychological research to follow and the consequence if these are broken
The British Psychological Society
How to deal with deception
Debrief- a post research interview were the pot is told the true alms of the research and full details of the study are eiven e g, knowledge of any other experimental groups?
pts should also be given the right to withdraw their data from publication.
pts must be reminded that their behaviour is typical/normal of the general Public, and in extreme cases if ppts feelembarrassed Or stressed as a result of the procedures used in the research, they should be offered counselling.
How to deal with informed consent
Participants should be given a consent form detailing the true nature and aims of the study.
A child under 16 cannot give their consent.
There are other ways to gain consent - the 3 P’s
1. Presumptive consent - this is gaining consent from a similar set of ppts who won’t actually be doing the study.
2. Prior informed consent - getting general consent from pts of things that ‘could’ happen.
3. Parental consent - when pts are too young to give consent this is gained from parents. (under 16)
If consent wasn’t gained from the pts in the study a debrief should be given and Ppts can give retrospective consent. pts may wish to withdraw their data if they do not consent.
How to deal with protection from harm
Right to withdraw - pts should be offered the right to withdraw at any point during or after the research has taken place.
Debrief- reassure the Ppts that their behaviour is normal - offer counselling
to all Ppts.
How to deal with confidentiality
Anonymity - All personal should be kept anonymous e.g. use of numbers, initials or fake names.
