Research Methods- Year 1 Flashcards
Why study research methods ?
We need to gather evidence to help develop and support psychological theories
Aim
general statement of what the researcher intends to investigate the purpose of the study.
Hypothesis
A clear, precise and testable statement that states the relationship between the variables to be investigated, stated at the outset of any study
Variables
Factors that change in an investigation. They are usually used in experiments to determine if changes in one thing result in changes to another
Independent variable
Researcher manipulates or it changes naturally so the effect on the DV can be measured
Dependent variable
Is measured by the researcher to see how it changed. Any effect on the DV should be caused by the IV
Levels of the independent variable
In most experiments the IV has two conditions, the control group and the experimental group
Operationalism
Turning abstract concepts from your aim into clearly defined variables that can be measured
Directional hypothesis (one tailed)
States the kind of difference or relationship between the IV and DV.
Non- directional hypothesis (Two tailed)
Simply predicts that there will be a difference between conditions.
How do researchers decide what type of hypothesis to use
- One tailed if previous research suggests an outcome.
- Two tailed if no previous research or it’s inconclusive
Extraneous variable
Any variable other than the IV that may have an effect on the DV (if it is not controlled). They do not vary systematically with the IV
Confounding variable
A kind of extraneous variable that systematically change with the IV.
Any variable other than the IV that may have affected the DV so we cannot be sure of the reason for the DV changing.
Participant variable
any individual differences between participants that may affect DV
Situational variables
any features of the experimental situation that may affect DV
Examples of participant variables
Personality, age, gender, motivation
Examples of situational variables
weather, instructions, temperature, time of day, noise
Demand characteristics
Any cue from the researcher or from the research situation that may be interpreted by participants as revealing the purpose of an investigation. This leads to a participant changing their behaviour within the research situation
Investigator effects
Any effect of the researcher’s behaviour that could change the outcome of the results.
How can we control extraneous and confounding variables ?
- standardisation- All participants should be subject to the same experimental conditions
- Randomisation- Using chance in order to control for the effects of bias in an experiment
Participants
People who take part in research
Population
the group of people from which the sample is drawn
Bias
when certain groups are under-or overrepresented in a sample (not representative)
Random sampling
Every member of the target population has an equal chance of being chosen.
How is random sampling done ?
- compile a list of all target population
- assign each a number
- select a sample using a random number generator
Advantages of random sampling
-No researcher bias
- Confounding variable should be distributed evenly
Disadvantages of random sampling
- Difficult to get a complete list of target population
- time consuming
- participants might not be willing to partake
Systematic sampling
Every nth member of the target population is selected. (e.g. every 5th person on the register)
How is systematic sampling done ?
- create list pf the target population in an order (e.g. alphabetical) - this is a sampling frame.
- take a sample from the list
Advantages of systematic sampling
-objective, avoids researcher bias as there is no influence once the system is chosen
Disadvantages of systematic sampling
- could draw a non-representative sample
- time consuming, costly
- participants may refuse to take part
Stratisfied sampling
composition of the sample reflects proportion of certain subgroups in the target population
How is stratified sampling done ?
- Identify different subgroups in the population
- work out the proportion of each group
- participants in each subgroup are selected randomly in the same proportion as the target population
Advantages of stratified sampling
- avoids researcher bias
- more representative of the whole population so findings are more generalizable
Disadvantages of stratified sampling
- stratification is never perfect, complete representation of population is not possible.
Opportunity sampling
sample from people who are available and willing when the study is carried out.
Advantages of opportunity sampling
- quick
- convinent
Disadvantages of opportunity sampling
- unrepresentable
- researcher bias
Volunteer sampling
self- selected sampling- participants become part of the study when asked or in response to an advert.
advantages of volunteer sampling
- convenient
- less time consuming
- no researcher bias
disadvantages of volunteer sampling
- often unrepresentative- volunteer bias
Experimental design
refers to how you allocate your participants to the different conditions in an experiment
what are the 3 experimental designs
- independent groups
- repeated measures
- matched pairs
Independent groups
Participants only take part in one condition
Requires a separate group for each condition
Results from each group are compared
Advantages of independent groups
- avoids order effects
- Reduces demand characteristics
Disadvantages of independent groups
- needs lots of participants (costly)
-differences between groups may affect the results (random allocation may help to overcome this)
Order effects
When the order of the conditions in an experiment has an effect on particular behaviour
Repeated measures
Participants take part in all conditions
Everyone experiences the control and the experimental condition
Results for the two conditions are then compared.
Advantages of repeated measures
- Avoids participant variables as everyone does all conditions
-fewer people needed
Disadvantages of repeated measures
-Order effect more likely-requires counterbalancing
-Demand characteristics more likely as participants are more likely to guess the aim
counterbalancing
Alternating the order in which participants take part in different conditions
Matched pairs
-Participants are matched in each condition for any characteristics that may affect performance (age,gender,IQ)
-Results are compared between members of each pair
Advantages of matched pairs
Reduces participant variables
reduces order effects and demand characteristics
Disadvantages of matched pairs
Very time consuming - costly
impossible to match pairs exactly (even for twins) may be unexpected confounding variables
Types of experiment
Lab, field, natural, Quasi
What is an experiment ?
There is an IV sometimes manipulated by the researcher
The effects of the IV on the DV are observed or measured so that the hypothesis can be tested
The participants are allocated randomly to the conditions, where possible.
Lab experiments strengths
control extraneous variables- increases objectivity + validity
- can be standardised, easy to replicate
Lab experiments limitations
Artificial conditions-low ecological validity, demand characteristics, experimenter bias, low mundane realism, ethics
Field experiment strengths
Greater ecological validity, more mundane realism, behaviour more valid, fewer demand characteristics
Field experiment limitations
Less control- more possible extraneous variables, harder to replicate, ethics
Natural experiments strengths
High ecological validity, can research areas that would make experiments impossible forethical reasons