Research Methods 1 Flashcards
What is the experimental method?
A scientific method involving the manipulation of variables to determine cause and effect. Participants are organised and allocated in a certain way. All procedures are standardised so that they are the same for all pps
What is a variable?
Any object, event or characteristic varying in some way
What is an independent variable?
The thing or factor that is manipulated in an experiment
What is a dependent variable?
The thing or factor that is measured by the researcher to see if the IV affected it
What is a control variable?
The variables which are held constant or limited in a research study because they could influence the outcomes of the experiment
What are extraneous variables?
Any other variables that could affect the DV, so we try to control these so that they don’t vary across any experimental conditions or between pps, e.g. participant variables (age), situational variables (noise levels) and experimenter variables (gender of experimenter)
What are confounding variables?
When an extraneous variable is not controlled, it confuses the results by affecting the dependent variable
What does it mean to operationalise a variable?
To clearly define a variable so that the IV can be manipulated and the DV can be measured. Some variables are very difficult to operationalise and therefore measure. Sometimes operationalising a variable means that we are only measuring one aspect, however, without accurate operationalisation, results can be unreliable and replicating the study to observe the validity becomes difficult
What are demand characteristics?
When conducting research, pps are not always passive, and spend time making sense of the situation. This is an extraneous variable and is difficult to control. Features of a study can help pps guess what the study is and the expected outcome
What can demand characteristics mean?
The pps guess the purpose of the study and try to please the researcher - the “please you” effect The pps guess the purpose of the study and try to upset it - the “screw you” effect The pps act unnaturally due to nervousness and fear of evaluation The pps act unnaturally due to social desirability bias
How can we avoid demand characteristics?
Single blind technique - pps are “blind” to the research aims with no idea of which condition they are in Double blind technique - both the pps and the researcher are blind to the research aims, reducing subconscious researcher cues/clues for certain behaviours, reducing investigator effects
What are investigator effects and give examples
When the investigator can subconsciously influence the results of the research - Physical characteristics (age, gender, ethnicity) - Personal characteristics (tone or volume of voice) - Unconscious bias in interpretation of data to support what they expected to find
What is a research aim?
A precise statement of why a study is taking place and what is being studied. It will describe the purpose of the research “The aim of the study is to investigate the effect of caffeine on reaction times”
What is a hypothesis?
A precise, testable prediction of what is expected to happen in an experiment
What is the experimental/alternative hypothesis?
This predicts that differences in the IV will lead to a change in the DV “Increasing levels of caffeine consumption will significantly affect reaction time”
What is a null hypothesis?
This predicts that changes in the IV will not affect the DV “Increasing levels of caffeine consumption will have no effect on reaction time”
What is a directional (one tailed) hypothesis?
Predicts the direction of the results/the actual direction of any change caused by the IV - uses words such as “smaller”, “greater”, “increase” and “decrease” “There will be a significant reduction in reaction times as a result of increased caffeine consumption”
What is a non-directional (two tailed) hypothesis?
Predicts that there will be a difference but does not predict the direction of the results/predicts that a change will be caused by the IV, but the direction of the change is unknown - uses words such as “lead to”, “change”, “difference”, “will have an effect on” “There will be a significant difference in the speed of reaction times as a result of caffeine consumption
Describe what a laboratory experiment is
Take place in controlled conditions/environments using standardised processes
What are the strengths of laboratory experiments?
- High levels of control of all variables - IV and DV are precisely operationalised and measured, increasing accuracy - If all extraneous variables are controlled, it is easier to establish cause and effect - the change in the DV must be due to the IV - High level of reliability because the experiment can be replicated
What are the weaknesses of laboratory experiments?
- Low ecological validity because it is not a real life environment - high levels of control make the situation artificial - Demand characteristics are more likely because pps are aware they are being tested - their behaviour may change unconsciously or consciously - Operationalising variables may mean they are less applicable to real life
Describe what a field experiment is
Take place in a real world setting rather than artificial environments. The IV is manipulated by the experimenter
What are the strengths of field experiments?
- High ecological validity because findings are applicable to real life settings - Avoids pp effects because they are not aware of the study
What are the weaknesses of field experiments?
- Low levels of reliability - it would be difficult to get the same findings in a natural environment because it has a low level of control to it - Harder to establish cause and effect
What is a natural experiment?
Takes place in a natural setting but the IV already exists naturally - the variable would have changed in real life whether or not it was being researched
What are the strengths of a natural experiment?
- High ecological validity as it is happening in the natural environment - No demand characteristics, especially if participants are unaware of the experiment - Practical and ethical reasons may mean this is the only method that can be used
What are the weaknesses of natural experiments?
- No control over extraneous variables - No direct manipulation of the IV, therefore it is more difficult to establish cause and effect - Difficult to replicate as conditions are unlikely to be exactly the same - Potential sample bias as groups are not selected in particular ways
What is a quasi experiment?
The IV simply exists and is based on a difference between people. It has not been manipulated; it simply exists. Pps are not randomly allocated to conditions - they fit that category by default. These differences can be tested in laboratory conditions
What are the strengths of quasi experiments?
Often carried out under controlled conditions and therefore share almost the same strengths and weaknesses as laboratory experiments. For example, there may be higher controlled studies with low ecological validity
What are the weaknesses of quasi experiments?
Because the allocation to the IV is not completely random, we cannot be certain that the IV has caused any change to the DV
What is meant by “experimental design”?
The way in which participants in a study are organised into conditions
What is a population?
The whole of a target group
What is a sample?
Part of a larger population - we test a sample as normally it is extremely difficult or maybe impossible to test an entire population
When is a sample biased or unrepresentative?
A sample may be selected in a way that means the selection is somehow biased to selecting certain pps and not others. This means that it may not represent the target population. This will be as a result of the sampling technique used
What is generalisability?
How effectively we can transfer the results from a sample to the entire population. If a sample is biased or unrepresentative of the target population, then the results may be considered less generalisable
What is a random sample?
Where each member of a population has an equal chance of being selected. For example, names could be selected by random number generators or out of a hat to avoid bias
What are the strengths of a random sample?
- Unbiased selection, meaning it should be more representative - A representative sample creates results that are more generalisable to the population
What are the weaknesses of random samples?
- Impractical - it is difficult to get full details of a target population, and not all members want to participate - Unbiased selection does not guarantee an unbiased sample, for example, by chance, all females could be selected
What is an opportunity sample?
Selecting pps who are available and willing to take part, such as asking people in a street, a class from school, or most commonly in university studies, undergraduates for convenience
What are the strengths of opportunity samples?
- Easy to create with people who are available - In a natural experiment, the researcher often has to select those who are naturally available
What are the weaknesses of an opportunity sample?
- The sample is likely to be biased and therefore unrepresentative as it may exclude certain pps. Therefore, it is hard to generalise results to the target population - Through self-selection, pps have the opportunity to decline, In this case, the sampling technique becomes self-selected
What is a volunteer (or self selected) sample?
People volunteer or self select to take part as pps. This is often by responding to an advert
What are the strengths of a volunteer (self selected) sample?
- The sample is easy to form as, other than advertising, the pps volunteer themselves - Pps are presumably keen to take part and therefore less likely to sabotage the study (screw you effect)
What are the weaknesses of a volunteer (self selected) sample?
- Volunteers are likely to be a certain type of person and therefore the sample is likely to be biased and unrepresentative. This may make results less generalisable - Volunteers may be eager to please, which increases the chance of demand characteristics
What is a systematic sample?
Involves taking every “nth” person from a list. The population size is calculated to work out the sampling interval
What are the strengths of systematic sampling?
- Unbiased selection and therefore more representative - Generalisable results (unless by chance every nth person has certain characteristics)
What are the weaknesses of systematic sampling?
Periodic traits - if by chance every nth person has a particular trait, the sample will not be representative
What is stratified sampling?
This attempts to overcome the potential issues with other techniques by creating a small scale reproduction of a population by dividing it into characteristics that are important for the research, such as age, social class and level of education, and then the population is randomly sampled within each stratum (category)
What are the strengths of a stratified sample?
- The sample should be representative as it is attempting to select from sub-groups within a population - Should be unbiased as the sample is randomly taken from the sub groups
What are the weaknesses of stratified sampling?
- This needs detailed knowledge of the population characteristics, which may be difficult to obtain or not always available - To divide a population into stratums and then randomly selecting from each can be very time consuming
Explain repeated measures
The same pps are used in both conditions
What are the strengths of repeated measures?
No participant variables
What are the weaknesses of repeated measures?
- Increased risk of demand characteristics - Order effects - Practice effects
Explain independent groups
The pps are allocated to two different groups, each only experiencing one condition
What are the strengths of independent groups?
- Less risk of demand characteristics - No order effects - No practice effects
What are the weaknesses of independent groups?
Risk of participant variables
Explain matched pairs
Pairs of participants are closely matched (using key characteristics/criteria, like age or gender) and are then randomly allocated to one of the experimental conditions. The perfect pair would be monozygotic twins
Describe the process of creating a matched pairs experiment
- Pps are tested on key criteria 2. 2 pps are matched based on these characteristics to form a matched pair 3. The pair are then separated - one is put into condition A and the other into condition B 4. This is then repeated for all of the selected pps in the sample 5. A group in condition A and a group in condition B are made as similar as possible based on the key characteristics initially tested
What are the strengths of matched pairs?
- Really makes the groups equal - Takes away pp variables
What are the weaknesses of matched pairs?
- Time consuming as pre-testing is needed - Difficult to match pps exactly - monozygotic twins are hard to find
What are order effects?
When an experiment is affected by the order in which a pp experiences the conditions - they may get bored or tired and so perform worse in the second condition
What are practice effects?
When a pp gets better in the second conditions due to the fact that they have had practice in the first condition