research methods Flashcards
what are the key concepts in used in the experimental method
- Aim
- Hypothesis
- Experimental method
Aim
a general expression of what the researcher intends to investigate
what is a hypothesis
a statement of what the researcher believes to be true
it should be operationalised i.e. clearly defined and measurable
what are the 3 types of hypothesis
- the null hypothesis: states that there will be no change in the dependent variable when the independent is manipulated
- directional hypothesis: states whether the change in dependent variable is greater or lesser, +ve or -ve
- Non directional hypothesis: doesn’t state the direction just that there is a difference, correlation or association
general research issues
(issues that can occur in general research)
(3)
- extraneous and confounding variables
- demand characteristics
- investigator effects
what are extraneous and confounding variables
- extraneous variables (EVs) are nuisance variables that do not vary systematically with the IV. a researcher may control some of these
- confounding variables (CV) change systematically with the IV so we cannot be sure if any observed change is the DV is due to the CV or the IV. CVs must be controlled.
what are demand characteristics
refers to any cue from the researcher or research situation that may reveal the aim of the study. this leads to the participant behaving unnaturally or at the demand of the research (doing what they think is wanted)
investigator effects
any effect of the investigator behaviour on the outcome of the research (the DV)
what are some research techniques used (4)
- randomisation
- standardisation
- control groups
- single blind and double blind
what is randomisation
the use of chance when designing investigations to control the effects of bias
what is standardisation
using exactly the same formalised procedures for all participants in a research study
what are control groups
control groups are used for the purpose of setting a comparison. they acta as a baseline and helps establish causation
what is single blind and double blind
single blind- is where a participant doesn’t know the aims of the study so the demand characteristics are reduced
double blind - both participants and researcher don’t know the aims of the study reduces demand characteristics and investigator effects
what are the 3 types of experimental method
- independent groups
- repeated measures
- matched pairs
what is independent groups
and evaluation
one group do condition A and a second group do condition B. participants should be randomly allocated to experimental groups
evaluation:
+ no order effects. participants are only tested once so can’t practise or become bored/ tired. this controls an important CV
+ will not guess aim. participants only tested once so are unlikely to guess the research aims. therefore behaviour may be more natural. no demand characteristics
- participant variables: the participants in the 2 groups are different, acting as EV / CV. may reduce validity of the study
- more participants: need twice as many participants as repeated measures for same data. more time spent recruiting which is expensive
what is repeated measures
evaluation
same participants take part in all conditions of an experiment. the order of conditions should be counterbalanced to avoid order effects
+ participant variables. the person in both conditions has the same characteristics. this controls an important CV
+ fewer participants: half the number of the participants needed in independent groups. less time and money spent recruiting participants
- order effect. participants may do better or worse when doing a similar task twice. reduces the validity
- participants may guess aim. participants may change their behaviour. this may reduce the validity of the results
what is matched pairs
evaluation
two groups of participants are used but they are also related to each other by being paired on participant variables that matter for the experiment
+ participant variables: participant matched on a variable that is relevant to the experiment. this enhances the validity of the results
+ no order effects: participants are only tested once so no practice or fatigue effects, this enhances the validity of the results
- matching pairs not perfect: matching is time consuming and can’t control all relevant variables. may not address participant variables
- more participants. need twice as many participants as in repeated measures for the same data more time spent recruiting which is expensive.
what are the 4 different types of experiments
- laboratory experiments
- field experiments
- natural experiments
- quasi experiment
what is a laboratory experiment
a control evironment where extraneous and confounding variables can be regulated
participants go to researcher
the IV is manipulated and the effect on the DV is recorder
what are the advantages of laboratory experiments
+ EVs and CVs can be controlled: this means that the effect of EVs and Cvs on the DV can be minimised. cause and effect between the IV and DV can be demonstrated (high internal validity)
+ can be easily replicated. due to the standardised procedures the experiment can be repeated. if the results are the same this confirms their validity
what are the limitations / disadvantages of laboratory experiments
- may lack generalisability. the controlled lab environment may be rather artificial and participants are aware they are being studied. thus behaviour may not be natural and cant be generalised to everyday life. (low external validity)
- demand characteristics. these are cues in the experimental situation that invite a particular response from participants. the results of the experiment may be explained by these cues rather than the effect on the IV
what is a field experiment
a natural setting. the researcher goes to participants
the IV is manipulated and the effect on the DV is recorded
what are some advantages of field experiments
+ more natural environment: participants more comfortable in their own environment. results may be more generalisable to everyday
+ participants are unaware of being studied. they are more likely to behave as they normally do so the findings can be generalised. the study as greater external validity
what are some limitations / disadvantages of field experiments
- more difficult to control CVs. observed changes in the DV may not be due to the IV, but to CVs instead. it is more difficult to establish cause and effect
- there are ethical issues: participants in a field experiment may not have given informed consent. this is an invasion of their privacy
what is a natural experiment
the experimenter does not manipulate the IV. the IV would have varied even if the experimenter wasn’t interested
DV may occur naturally or may be measured by the experimenter
what are some advantages of a natural experiment
+ may be the only ethical option: it may be unethical to manipulate the IV. a natural experiment may be the only way causal research can be done for such topics
+ greater external validity: natural experiments involve real life issues, such as the effect of natural disaster on stress levels. this means the findings are more relevant to real experiences
what are some disadvantages / limitations of a natural experiment
- the natural event may only occur rarely: many natural events are one-offs and this reduces the opportunity for research. this may limit the scope for generalising findings to other similar situations
- participants are not randomly allocated: the experimenter has no control over which participant are placed in which condition as the IV is pre-existing. may results in CVs that aren’t controlled.
what is a quasi experiment
IV is based on a preexisting difference between people e.g age or gender. no one has manipulated this variable, it simply exists
DV may be naturally occurring or may be measured by the experimenter.
what are some advantages of a quasi experiment
+ there is often high control: often carried out under controlled conditions and therefore shares some of the strengths of lab experiments. this means increased confidence about drawing causal conclusions
+ comparisons can be made between people. in a quasi experiment the IV is the difference between people e.g people with and without autism. this means that comparisons between different types of people can be made
what are some disadvantages of a quasi experiment
- participants are not randomly allocated: the experimenter has no control over which participant are placed in which condition as the IV is pre-existing. participant variables may have caused the change in the DV acting as a CV
- causal relationship not demonstrated. the researcher does not manipulate / control the IV. we cannot say for certain that any change in the DV was due to the IV
what are the 5 different types of sampling
- opportunity sample
- volunteer sample
- random sample
- systematic sample
- stratified sample
what is a population
the large group of people that a research is interested in studying
what is a sample
it is usually not possible to include all members of the population in the study so a smaller group is selected
what does a sample have to be in order to make generalisations to the population
the sample that is drawn should be representative of the population so generalisations can be made
what makes a sample bias
the majority of samples are biased
this means that certain groups may be over or under represented.
what is an opportunity sample.
how do you get an opportunity sample
people who are simply most available i.e the ones who are nearest / easiest to obtain
ask people nearby
what are the strengths and weaknesses of an opportunity sample
+ quick method: is convenient because you just make use of the people who are closest. this make it one of the most popular sampling methods
- inevitable biased. the sample is unrepresentative of the target population as it is drawn from a very specific area. this means that the findings cannot be generalised.
what is a volunteer sample
and how do you obtain one
self selecting. the participants select themselves
can be obtained by advertising
what are the strengths and weaknesses of using a volunteer sample
+ participants are wiling, they have selected themselves and know how much time and effort is involved. likely to engage more than opportunity sample
- likely to be a biased sample: participants may share certain traits e.g keen and curious. generalisation limited due to the volunteer bias.
what is a random sample
how do you obtain one
every person in the target population has an equal chance of being selected
lottery method. all members of the target population are given a number and use a random number generator
what are the strengths and weaknesses of using a random sample
+ potentially unbiased. the research has no influence over who is selected. free from research bias
- representation not guaranteed. still possible that a random method may produce a biased sample. limits ability to generalise
what is a systematic sample
how can you obtain one
sampling frame. participants are selected using a set pattern (sampling frame)
every nth person is selected from a list of the target population
what are the strengths and weaknesses of a systematic sample
+ unbiased. the first item is usually selected at random objective method
- time and effort. a complete list of the population is required. may as well use random sampling.
what is a stratified sample
how can you obtain one
frequency. participants are selected according to their frequency in the target population
subgroups (or strata) are identified, such as gender or age groups. the relative percentages of the subgroups in the population are reflected in the sample
what are the strengths and weaknesses of a stratified sample
+ representative method. the characteristics of the target population are represented. generalisability more likely than other methods
- stratification is not perfect. strata cannot cannot reflect all the way in the people are different. complete representation is not possible
what are the 4 ethical issues
- informed consent
- deception
- protection from harm
- privacy and confidentiality
what is the abbreviation for ethical issues
can - informed consent do - debrief cant - confidentiality do - deception with - withdrawal participants - protection from harm
informed consent
participants should be able to make an informed judgement about whether to take part
too much information may affect participant’s behaviour so there are some alternatives:
- presumptive - ask a similar group
- prior general - agree to be deceived
- retrospective - get consent after the study
what are the 3 alternative forms of consent
- presumptive - ask a similar group
- prior general - agree to be deceived
- retrospective - get consent after the study
deception
deliberately misleading or withholding information so consent is not informed.
a debrief is given at the end of a study
what should be included in the debrief (5)
- the true aims of the investigation
- details that were not given during the study such as other groups or conditions
- what their data will be used for
- there right to withhold data
- reassured that their behaviour was typical/ normal (protection from harm)
protection from harm
participants should be at no more risk than they would be in everyday life
- should be given the right to withdraw at each stage of the research process
- should be reassured that their behaviour was typical / normal during the debriefing
- researchers should provide counselling if participants have been distressed.