Formulation of Testable Hypotheses (AQA GCSE Psychology)
Revision Note
Written by: Claire Neeson
Reviewed by: Lucy Vinson
The alternative hypothesis
A hypothesis is a testable statement written as a prediction of what the researcher expects to find as a result of their experiment
The alternative hypothesis (AH) should include the independent variable (IV) and the dependent variable (DV)
Both IV and DV in the AH need to be operationalised - giving specifics on how each variable is to be manipulated (IV) and measured (DV), for example:
Operationalising the IV = exposing some children to an aggressive adult model whilst other children are not exposed to an aggressive adult model
Operationalising the DV = the number of imitative acts of aggression performed by the child
The AH should include (very brief) details of how, for example, 'aggression' as the variable is to be manipulated and measured:
The AH for the above study on aggression could be written as follows:
Children who are exposed to an aggressive adult model will perform more acts of imitative aggression than children who have not been exposed to an aggressive adult model
The AH predicts the effect of the IV on the DV i.e. it is the hypothesis of ‘difference’ (between conditions)
Examiner Tips and Tricks
It is important not to get confused between the alternative hypothesis and the null hypothesis. One way of remembering which is which is to remember that ‘null’ means ‘nothing’ i.e. no difference in conditions.
The null hypothesis
All published psychological research must include the null hypothesis (NH)
The NH is what all research starts with
The NH has to begin with the idea that the IV will not affect the DV because until the experiment is run and the results are analysed it is impossible to state anything else
For example:
A researcher thinks that memorising a list of words while loud music is playing will result in a lower score than when the words are memorised in silence - but they have to test this prediction using an experiment
The researcher must then write an NH which assumes ‘no difference’ until the results of the experiment have confirmed (or not confirmed) their prediction: Playing loud music will not affect memorising a list of words
If the experiment shows no difference between conditions then the NH must be kept/accepted; if the experiment shows a difference in conditions then the NH can be rejected
The NH for the study on aggression could be written as follows:
There will be no difference in children's acts of imitative aggression depending on whether they have observed an aggressive adult model or a non-aggressive adult model
Worked Example
Here is an example of a question you might be asked on this topic - for AO2.
AO2: You need to apply your knowledge and understanding, usually referring to the ‘stem’ in order to do so (the stem is the example given before the question)
Professor Premleague is sure that drinking cola before a match will improve football player’s ability to score penalties. His IV is whether players have drunk cola (or not) before attempting to score 10 penalties in a row.
Question: Write a null hypothesis the researcher can use in this experiment. [2]
Model answer:
There will be no difference in the number of goals scored (the DV) depending on whether football players have drunk cola or not drunk cola (the IV) before attempting the penalties.
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