RM1- Types of Experiments, Variables, Hypotheses and Experimental Designs Flashcards
hypothesis
a state of measure of prediction
independent variable
what you change as the researcher
dependent variable
what you measure
extraneous variables
other variables that may affect our results
participant sample
the people you use in the study
quantitative
numerical data
nomothetic approach
use quantitative data analysis and preferably large samples of participants to explain behaviour
laboratory experiment
conducted in a controlled environment
the researcher directly manipulates the iV
field experiment
conducted in a real world setting
the researcher directly manipulates the IV
quasi experiment
the reswarcher has no control over the IV
it is a characteristic of the individual
can put a task in place to measure the DV
has some control over EVs
natural experiment
the researcher has no control over the IV- naturally occuring
e.g. studying effects of real life events
DV is naturally occuring
little control over EVs
what is internal validity?
is the research accurately measuring what is claims to?
what is external validity?
can the research findings be accurately generalised beyond the study itself?
3 types of external validity
temporal
population
ecological
what is ecological validity
-setting/ environment
-are participants eliciting natural behaviors?
-natural or artificial setting?
a lab experiment would lack this validity
what is temporal validity
-eras/ times
-attitudes can change overtime- homosexuality was once defined as a mental illness
what is population validity
-people
can they guess the aims of the research and display demand characteristics- change their behaviour
occupation
sex
age
cultural background
demand characteristics
behaving in a way we think is expected /what they want to find
cause and effect
being confident that one variable has led to a change in another- IV caused effect on DV
reliability
how consistent the results are likely to be
standardised procedures
exactly the same procedure for every person
lab experiments and reliability
HIGH
-use standardised procedures
-take place in highly controlled settings
-extraneous variables are limited
-study can be easily replicated
lab experiments and ecological validity
LOW
-take place in highly controlled settings
-artificial setting to the participant
-behaviour is unnatural
lab experiments and internal validity
HIGH
-strict level of control over extraneous variables
-isolation of the effect of IV on DV
-we can establish cause and effect relationships
-confident that a change in the DV is due to a change in the IV
but
lab experiments and internal validity
LOW
-demand characteristics are likely in unnatural settings
-may use environment or researcher for clues to how to act
-not realistic behaviour
field experiments and reliability
LOW
-use standardised procedures but take place in a natural environment
-less control over extraneous variables
-study is more unpredictable- can’t always be replicated
field experiments and ecological validity
HIGH
-take place in natural environments
-behaviour is more natural and realistic
field experiments and internal validity
HIGH
-demand characteristics are less likely
-more accurate
-behave more naturally
but
field experiments and internal validity
LOW
-can’t control EV- decrease validity
-cannot establish cause and effect
field experiments and ethical issues
-may not be aware they are being studied
-cannot give informed consent
quasi experiments and internal validity
LOW
-ramdon allocation of participants is not possible- IV is a characteristic- can’t be changed
-participant variables may confound the results- cannot say if they are a direct result of the DV.
strengths of natural experiments
-allow researches to investigate topics that would be impractical and unethical to investigate using other experimental methods
-ecological validity is extremely high compared to laboratory experiment
-demand characteristics are greatly reduced compared to a lab experiment
limitations of natural experiments
-no random allocation of participants
-researcher has no control over the environment
what is a variable
anything in a research study that can vary
the independent variable….
is taken advantage of if its naturally occurring
the dependent variable……
is what we measure
what is operationalising variables
expressing variables in a form that can be measured accurately.
how would we operationalise an IV?
what different conditions could pps be put into?
e.g. if gender- male or female
sociability- introvert or extrovert
how would be operationlise a DV?
how will it be precisely measured?
e.g. driving ability- score on driving test
memory- number of numbers or words remembered and recalled
what are extraneous variables
variables extra to the independent variable that you are studying that might impact upon your dependent variable
why should you control ev’s
allows us to establish a cause and effect
-to conclude that our results have greater internal validity
what are the four different types of extraneous variables?
participant variables
situational variables
demand characteristics
experimenter effects
what are participant variables?
-individual characteristics of participants that could affect study results
how can we control PV?
random allocation
-random deciding process
-unbias
what are situational variables?
-a change in environmental conditions that can alter behaviours in studies
how can we control situational variables?
standardised procedures
-ensures every participant is treated the same way and with the same instructions, materials etc
what are experimenter effects?
unintentional/ unconscious hints that the researchers may show which influence the study outcomes
how can we control experimenter effects?
double blind
-reduces observer and participant bias
-neither know who is receiving a particular treatment
what are demand characteristics?
characteristics that pps believe follow the expectations researchers are looking for
how can we control demand characteristics?
double blind
-researchers cannot show subtly hints cuing this behaviour
what are confounding variables?
a form of extraneous variable that has not been controlled for that could impact the dependent variable
characteristics of confounding variables
-hard to control
-varies systematically with the IV
what problem arises with lots of confounding variables?
weakens the validity of research
-cannot definitively establish cause and effect
-the IV is not causing impact on DV, instead its the CV
what is a research aim?
identifies the purpose of the investigation
-what is the researcher trying to find out?
what is an operationalised hypothesis?
an operationalised hypothesis is a precise, testable statement about the expected outcome of a piece of research.
what are the 2 types of hypothesis?
null and alternate
what is a null hypothesis?
null= nothing
-statement that the researcher will not find any results of statistical significance
there will be difference between the results (DV) for each condition (IV) and any difference will be due to chance
what are the two types of alternate hypothesis?
directional and non-directional
what is a non-directional hypothesis?
when a researcher is unsure of the likely outcome of the findings for a study
-predict a more general outcome
e.g. there will be a significant difference between ……
what is a directional hypothesis?
when a researcher has a good idea what results are likely to be in a study
-predict a more specific outcome
e.g. participants will give more/ higher/ greater/ increase
experimental design
refers to how participants are organised into conditions of the independent variable
order effects
occur when participants are doing a task more than once, may become practiced and fatigued
demand characteristics
cues that the participant is able to use to work out what the researcher is looking for or how they expect the participant to behave
participant variables
characteristics of the participants that could affect the DV if they differ between experimental conditions e.g. age, gender, personalities and intelligence
what are the three experimental designs?
independent groups
repeated measures
matched pairs
describe independent groups design
different participants take part in each condition of the IV, only complete one condition
-reduces order effects
-reduces chance of demand characteristics
describe repeated measures design
the same participants take part in each condition of the IV, takes part twice or more
-used to study the change in something
-reduces participant variables
-only need a small sample
describe matched pairs design
different participants take part in each condition of the IV, they are matched on key variables with a participant in the other condition, similar characteristics form a pair.
-in the pair they are randomly allocated into one of the experimental conditions
-minimises participant variables
-reduces order effects
strengths of independent design
no order effects
-take part in one condition
-not fatigued of practiced
-more accurate
more valid
-reduces demand characteristics
-behave more naturally
weaknesses of independent design
-validity is affected
-PV affect findings, only take part in one condition
-different people each time
strengths of repeated measures
valid results
-PV are controlled for- take part in all conditions
weaknesses of repeated measures
-demand characteristics
affecting validity, may change behaviour accordingly
-order effects
participate in all conditions, inaccurate
strengths of matched pairs
reduces confounding variables
-takes part once
-one set of materials needs to be made
increased validity
-one condition is experienced
-reduced order effects
reduced PV
-randomly allocated into one condition
-no demand characteristics
weaknesses of matched pairs
PV only reduced not stopped
-pairs are not identical- still will be some differences
-affecting accuracy
-becomes time consuming and difficult
