research methods-experimental methods Flashcards
what is a theory
a coherent explanation of the relationship between two or more variables
what is an aim
the intended purpose for an investigation
why its being carried out
what the research investigation is actually trying to discover
what is a hypothesis
a precise testable statement which is a general prediction made at the beginning of an investigation about what the researcher expects to happen
what is the group where the IV happens
experimental group
what is the baseline comparison group called
control group
what is an operationalised variable
where the IV and DV are defined so that they can be measured
this will provide quantitative data
what is a positive of operationalizing variables
enables other psychologists to replicate your research to see if your results are reliable(consistent)
what is a negative of operationalizing variables
operational definitions tend to be fairly aribitary narrowing the scape of research
if a hypothesis it tested in an experiment its called
experimental hypothesis
what is a hypothesis tested in another method
alternative hypothesis
what is a directional (one tailed) hypothesis
predicts the direction the results are expected to occur
they are used when previous theory or existing research evidence suggests the findings of a study will go in a particular direction
EG-children who spend more than 20 hours a week in daycare WILL behave MORE aggressively than children who spend less than 20 hours a week
what is a non-directional (two-tailed) hypothesis
does not predict the expected direction of the results
its used when there is no reference to existing research evidence
EG-children who spend more than 20 hours a week in daycare WILL SIGNIFICANTLY DIFFER in how aggressive they are compare to children that spend less than 20 hours
what is a null hypothesis
no relationship between the variables
we reject the alternative hypothesis and accept our null hypothesis when the difference found is too small to be significant
EG- there will be NO SIGNIFICANT DIFFERENCE between the aggression scores for children who spend more than 20 hours a week in day care and those who spend less than 20 hours a week in daycare. ANY DIFFERENCE FOUND IS DUE TO CHANCE
what is a extraneous variable
any variable other than the IV that caused the change in the DV
what is a confounding variable
its an extraneous variable that hasn’t been controlled and has varied systematically with the IV and therefore affected the DV/results
what are the three examples of extraneous variables
situational
participant
experimenter
what is a situational variable
anything from the environment that could cause a change in the DV
they have to be RELEVANT to the experiment EG-if you were testing memory and some participants had to cope with more noise than other it might affect your results
they are controlled though standardization ensuring the only thing that differs between the two groups is the IV
what is a participant variable
-characteristics and differences to do with the individual taking part eg-age, gender, IQ, and experience
-eg-if you were testing driving behaviour and some of your participants were tired that may affect results
-they are controlled through experimental design eg-matched base pairs and by randomly allocating participants to conditions which helps reduce bias
what is a experimenter variable
-it refers to the expectation, appearance, behaviour, gender and personality type of the researcher that may influence the way a participant responds eg-female researcher asking a male participant for his attitude towards women
-they are subtle cues given by the researcher that can bias the outcome of the study
-the hawthorne effect is an example of an experimenter effect, this is where the presence of a researcher can affect the performance of the participant
how do psychologists ensure there experiment is valid
by eliminating or controlling any extraneous variables so they can be sure the IV affects the DV
what should you do with extraneous variables and why
eliminate them
impacts upon validity
how can unwanted variables result
from random or constant error
what is a random error
-participants state of mind
-motivation
-previous experience
-you can counteract this by random allocation of participants
what is a constant error
it can be eliminated by good experiental design eg-counterbalancing
how do you conduct counterbalancing
half the participants do condition A followed by condition B and the other half do vice versa
what is counterbalancing
counterbalancing is a technique used to deal with order effects when using a repeated measure design
how do you avoid confounding variables
by holding theme constant
eg-if you think time of day may be relevant to your study make sure all participants were tested at the same time of day
how do you control extraneous variables
randomization-this is when trials are presented in a random order to avoid any bias
standardization-keeping the procedure the same
what is a single blind procedure
this is when the participant’s do not know the hypothesis and do not know which condition they are in in the experiment
what is the purpose of a single blind procedure
so participants don’t show demand characteristics which in turn improves validity
what is a double blind procedure
where both the researcher and participant don’t know the hypothesis and what condition they are in
what is the purpose of a double blind procedure
reduces researcher bias
what is a research method
the research method refers to the way in which psychologists go about collecting their data
what are the 4 types of experimental methods
-laboratory
-field
-natural
-quasi
what is a laboratory experiment
-takes place under highly controlled conditions
-the Iv is manipulated and all other variables are controlled so we can see the effects of the manipulation on the DV
-a common design is to have an experimental (does something) and control condition (doesn’t do anything)
-the control condition provides a baseline measure-what the dependent variable would be like without any manipulation
-participants may be aware they are taking part in an experiment due to the contrived nature of the situation
-they have random allocation of participants to conditions
why do laboratory experiments randomly allocate participants
reduces bias which improves validity /helps reduce random errors
what are the results of the experimental group compared against
control condition/baseline measure-what the dependent variable would be without manipulation
-this is important as otherwise the “normal” situation would not be known
what is controlled in a lab experiment and why
participant and situation variables so you can be sure they don’t affect the DV so the only thing affecting the IV is the DV
strength of lab experiment
(high levels of control)
the high level of control in lab experiments means that many extraneous variables can be eliminated or controlled which means we can be more confident measuring a cause-and-effect relationship between the IV and DV so its more internally valid
what does the high level of control in the procedure of a lab experiment mean
the high level of control means that the procedure can be highly standardized which means that its more easily replicated to check the reliability of the results
weakness of lab experiment
(high levels of control)
the high level of control means that the research often lacks mundane realism as it doesn’t reflect everyday life
consequently, the results lack ecological validity and cannot be applied to situations beyond the laboratory
weakness of a lab experiement
(artificiality and formality of the setting)
the artificiality and formality of the setting can result in participants displaying social desirability bias/demand characteristics. These confound the results reducing internal and ecological validity
weakness of a lab experiment
(studying all aspects of human behaviour)
they are not suitable for studying all aspects of human behavior, for example when the behavior in question takes month or years to develop or when its unethical or impractical to manipulate the IV eg-scitosphrinia
what is a field experiment
-takes place in the real world
-takes place in participants everyday setting/usual environment
-researcher still manipulates IV
strength of field experiment
(occurring in everyday setting)
strength of field experiment
ecological validity as it occurs in participants everyday setting
strength of field experiment
(in natural environment)
strength of field experiment
demand characteristics are less likely to affect the behavior of participants as they are in their natural setting and may be unaware the research is taking part
therefore, their behavior is more likely to reflect their typical behavior in that situation
weakness of field experiment
(Lack of control)
weakness of field experiment
they lack control of variables. These variables can then become confounding variables
-this means we cant be sure the only thing affecting the IV is the DV
weakness of field experiment
(unethical)
weakness of field experiment
they many be unaware they are taking part in research and are therefore unable to give informed consent
it breaks the ethical guideline of deception however they could overcome this by giving retrospective consent
what is a natural experiment
-the researcher does not manipulate the IV as it would be impractical/unethical to do so
-the IV is something that is naturally occurring eg-brain damage
-as the groups are pre existing the researcher has no control over who is in each condition
-the DV may be measured under laboratory conditions
what is a quasi experiment
-when the IV is a difference that already exists eg-gender, age, personality type
-the IV is therefore not manipulated or controlled by the researcher
-random allocation is also not possible as as the IV is a characteristic of the person
-the DV may be measured under laboratory conditions
what is the main difference between natural and quasi experiments
natural-an experiment where the change in the IV has not been brought by the experimenter but would’ve happened anyway
quasi-an experiment in which the IV has not been determined by anyone, the variable simply exists
What are some strengths of natural and quasi experiments
-they enable psychologists to conduct research when it would have been unethical to manipulate the IV
-it can be more ecologically valid as the researcher has not manipulated the IV however if the DV is measured under artificial conditions this can be undermines
-Its more ethical as the IV has occurred naturally so has not been manipulated by the researcher so the researcher has not altered participant behavior
What is a weakness of natural and quasi experiments
-you cannot demonstrate causal relationships as the IV has not been directly manipulated so there could be other confounding variables that can’t be controlled as random allocation isn’t possible
-id the DV is measured under artificial conditions then the same weaknesses of lab experiments will apply
What is a weakness of natural experiments
-the situation is rare so there are only limited research opportunities to replicate the study and establish reliability
what is experimental designs
different ways of organizing your participants
we use this to control participant variable
what is independent group design
-where different participants are used in each condition so each participant only does one condition
strengths of independent group designs
-each participant is only exposed to one condition so demand characteristics should be minimized so the experiment is more internally valid
-order effects are minimized as there are different participants in each condition
-the same stimulus material can be used for both condition so it can’t act as a confounding variable
weakness of independent group designs
-the groups consist of different participants participant variables may confound the results which means the study lacks internal validity however this can be reduced through random allocation
-each participant can only be used once so more are needed. This is a practical issue as its time consuming. It could decrease validity as a smaller sample means anomalous results will have more impact on a set of data
what are order effects
when participation in one condition affects performance in another
get better=through practice
get worse=due to boredom or fatigue
why do we randomly allocate percipients to conditions
-characteristics of the participant do not vary systematically between each condition
-reduces researcher bias
-reduces participant variables
how do we randomly allocate participants
writing participants names and putting them in a hat
-shaking it up
-allocatin some to conditon A and some to conditon B
-having to ring up and ask if they will take part
-if they won’t discard the paper
what is a repeated measures design
exposing participants to each of the experimental conditions and therefore participants are being tested against themselves
what are two strengths of a repeated measure design
-practical benefits as its cheaper and easier as you don’t need as many people
participant variables are minimized eg-if they are moody in one condition they will be moody in another
what are three weaknesses of a repeated measure design
-order effects may occur as they have done it before so may get better through practice or worse due to boredom or fatigue which will affect validity however, we can reduce this through counterbalancing
-demand characteristics are more likely to occur as they may have guessed the aim of the study which affects internal validity
-different stimulus material has to be used so it may act as a confounding variable which reduces internal validity
what is counterbalancing
its used to control for order effect
-half the participants do condition A followed by B and the other half do condition B followed by A
what is a matched pair design
-matching participants on one condition as closely as possible with participants on the second condition
-eg-age gender iq
-the assumption is that the pairings are similar so you can treat them as the same person
what are three advantages of a matched pair design
-participant variables are minimized in the factors you have matched increasing the internal validity of the study
-participants take part in one condition so order effects are less of a problem
-the same stimulus material can be used for both conditions, so it won’t act as a confounding variable
-demand characteristics are minimized as each participant only takes part in one condition
what are three weaknesses of a matched pair design
-if a practical issue as its costly and time consuming to match variables
-a large number of potential participants are needed so matches may not be found for everyone
-participant variables may confound the results as they can’t be matched on all characteristics
what are investigator effects
any unintentional influence of the researcher’s behavior on participants data
eg-approving/disapproving looks
investigators-gender,age,appearance
how can investigator effects be minimised
through double blind procedure
what is a volunteer sample
-where people choose to take part in a study. it is a self-selected sample
-psychologists may put notices,adverts or posters asking for people to take part
two advantages of a volunteer sample
-quicker and easier way of gaining a sample which is a practical strength
-its more ethical as participants are choosing to take part in your research
what is a disadvantage of volunteer sample
-there may be bias as you tend to get the same helpful, keen, curious personality types which decreases population validity as you can’t generalize to the wider population
-only people that see the sample have a chance of being selected
what is opportunity sampling
asking people who fit the characteristics of the target population if they are available and willing to participate in the experiment
advantages of an opportunity sample
-its a quicker and easier way of gaining a sample which is a practical strength so will likely save money
disadvantage of a opportunity sample
-there may be researcher bias as they are choosing approachable people who they want to ask this means the sample is not representative and lacks population validity
what is random sampling
-each member of the target population has an equal chance of being selected
-putting all the name into a hat
what is an advantage of a random sample
-provides a unbiased and representative sample as everyone has an equal chance of being picked
-free from researcher bias as they aren’t choosing who is taking part
what is a disadvantage of random sampling
-time consuming-practical issue
-a complete list of the target population is hard to obtain
-you still may end up with a unrepresentative sample by chance
what is systematic sampling
having a list of the target population and taking every nth person from the list
advantages of systematic sampling
there’s no researcher bias as they have no influence over who is chosen which improves validity
what are some disadvantages of a systematic sample
time consuming which is a practical disadvantage
what is a stratified sample
sampling technique in which participants are selected in proportion to their frequency in the population
advantages of stratified sampling
-it should be more demographically representative
-sub groups can be chosen according to variables considered to be important by the researcher. This increases control over extraneous variables
disadvantages of stratified sampling
-the decision about which sub groups to use may be biased reducing the representivness of the sample
-the sub groups identified do not reflect the individual differences within that sub-group
-its time consuming as relevant sub-groups have to be identified and proportions have to be calculated
what is a pilot study
a small scale trial run of the actual study with a small number of participants
what is the aim of conducting a pilot study
to see if there are any problems with
-the design
-the instructions for participants
-the measuring equipment being used
what does conducting a pilot study allow the researcher to save
-it allows them to see what needs to be adjusted for the actual study without having investing a large amount of time and money
what does a pilot study check
it checks the practicalities (method) of the study
