Experimental methods Flashcards
Define research aims
An aim is a statement of study’s purpose
Researchers should state the aim beforehand so that its clear what the study intends to investigate
Define experimental method
A researcher causes the independent variable (IV) to vary and records the effect of the IV on the dependent variable (DV)
In psychology, what 4 things is a hypothesis?
- A clear statement
- A prediction
- Testable
- Formulated at the beginning of the research process
Hypothesises can be what two things?
Directional or non-directional
Why do psychologists create a hypothesis?
Psychologists start with a theory which is a general idea about behaviour and then develop a hypothesis which makes the theory testable
Describe a directional (1 tailed) hypothesis
The researcher makes clear the sort of difference that it anticipated between two conditions or two groups
Directional hypothesis use words such as ‘more’ or ‘less, ‘higher’ or ‘lower’, ‘faster’ or ‘slower’
Give an example of a directional hypothesis
People who drink Red Bull become more talkative than people who don’t/ people who drink water are less talkative than people who drink Red Bull
Describe a non-directional hypothesis
This simply states that there is a difference between conditions or groups of people but the nature of the difference is not specified
Give an example of a non-directional hypothesis
People who drink Red Bull differ in terms of talkativeness compared with people who don’t drink Red Bull
What is a null hypothesis?
H0 predicts no significant relationships or difference between variables, meaning any observed effect is due to chance
Give an example of null hypothesis
If a researcher is investigating whether a new drug improves memory, the null hypothesis would state: “that there is no significant difference in memory scores between participants who recieve the drug and those who recieve a placebo”
If the results of a study are statistically significant, the null hypothesis is rejected, meaning there is evidence to support the alternative hypothesis
Which hypothesis is chosen when a theory or the findings or previous research suggest a particular outcome?
Directional
Which hypothesis is chosen when there is no theory or previous research, or if findings from earlier studies are contradictory?
Non-directional
What do you need to include in a hypothesis?
- The IV and DV are clear and measurable
- You have stated the relationship between the IV and DV and not stated the aim
- You have selected the appropriate hypothesis (directional or non-directional)
What is a variable?
Any ‘thing’ that can vary or change within an investigation
Variables are generally used in experiments to determine if changes in one thing result in changes in another
In an experiment, the researcher does what to the independent variable (IV)?
Changes/ manipulates
In an experiment, the researcher does what to the dependant variable (DV)?
Records/ measures the effect of the change
What should all the other variables that might potentially affect the DV do and why?
Should remain constant - this is so the researcher can be confident that any change in the DV was due to the IV
What is the mnemonic to help remember what variable does what?
Dairy Milk = Dependant Measures
Ice Cream = Independent Changes
In order to test the effects of the IV you need to have what?
Different experimental conditions - a comparison
For example:
In an experiment to see whether drinking Red Bull affects talkativeness, you could either:
Compare talkativeness before and after drinking Red Bull with each participant
OR
Compare 2 groups of participants - one group drinks Red Bull and the other drinks water
In either of the examples, the conditions are no Red Bull or drinking Red Bull
What is operationalisation of variables?
Clearly defining variables in terms of how they can be measured
Many studies that psychologists conduct are interested in social behaviour, intelligence or thinking. These topics are often a ‘little fuzzy’ and not easy to define
Because of this, the researcher must make sure the variables being investigated are as ‘unfuzzy’ and measureable as possible
