Research Methods: The Experimental Method Learning Objectives: To identify the difference between aims and hypothesis. To identify IV and DV.

Booklet In groups, think about how you go about designing a study to test the idea that violence on TV makes people aggressive. Write down all of your ideas below and share them with the rest of the class

Aim When designing any psychological study the researcher has to have an Aim In psychological research aims are developed from theories “An aim is more general statement and tells us why the study is being conducted i.e. the purpose of the investigation”

Research Aim Try to complete this statement:- “The aim of my research is to find out more about ….” Some suggested phrases include.. …why some people… …whether some people… …how people… …if people…

Watch the following clips and write down the aim of each investigation: Investigation 1: ‘Obeying a Man in Uniform’ https://www.youtube.com/watch?v=bgGT_EhyX7c Investigation 2: “The Halo Effect” https://www.youtube.com/watch?v=WqTSBVuSH7o

HYPOTHESIS Now we have an aim, we need to formulate a hypothesis. A hypothesis is a statement made at the start of a study and clearly states the relationship between variables as stated by the theory. E.G Drinking energy drinks causes people to be more talkative.

Hypotheses When you have decided your research aim then you need to formulate two hypotheses:- The Null Hypothesis The Alternative Hypothesis The Null Hypothesis says ‘there will be no difference...’ The Alternative Hypothesis says ‘there will be a difference…’

THE NULL HYPOTHESIS The null hypothesis is written alongside the alternative (or experimental if the research is an experiment) hypothesis in order to make the scientific prediction complete. A null hypothesis predicts that any differences between the sets of results in the experiment are due to CHANCE ALONE; as psychologists we must accept that we can never rule out the possibility that any results gained may be simply due to chance.

Look back again at the 4 ideas that the psychologist head made on page 2, then write a hypothesis for each of those ideas.

IVs and DVs In an experiment a researcher changes or manipulates the independent variable (IV) and records or measures the dependent variable (DV). All other variables (in a scientific experiment) that may affect the DV should remain constant -So we can be confident that cause of the effect on the DV was the IV alone.

Variables : The things we measure or manipulate in a psychology. The variable which is being manipulated by the researcher is called the independent variable. dependent variable is the change in behaviour measured by the researcher. All other variables which might affect the results and therefore give us a false set of results are called confounding variables (also referred to as random variables).

What is the Iv and Dv Drug A affects memory Bulls will charge more often when presented with a red rag than a blue rag. Social class affects IQ scores First children learn to speak earlier than second children

Activity booklet

Operationalising variables Means making something clear.   When conducting experiments it is important to operationalise the variables. That is, stating a clear way that the independent variable is going to be manipulated and the dependent variable is to be measured. For example if an experiment was to be carried out to see if time of day affected memory it would be important to operationalise the variables of time of day and memory. We might operationalise time of day as 10am and 10pm and operationalise memory as performance on a memory task.

ANOTHER EXAMPLE To see the effect of happiness on success in exams you would need to operationalise. Happiness- score on a scale of happiness Success in exams-The score they have on A Level exams.

Number of words recalled Independent Variable Caffeine influences Dependent Variable Number of words recalled Time of day 2 Conditions Tea/ Coffee Extraneous Variables Noise

Extraneous variables A general term for any other variable other than the IV that might effect the DV. If extraneous variables are important enough to provide alternative explanations for an effect, these become confounding variables. Participant variables: Variables that are connected with any characteristics of an individual participant i.e. age, intelligence, motivation, experience, gender & personality. Situational variables: Variables connected with the research situation i.e. temperature, instructions, time of day, noise materials used in the investigation.

Psychologists try to control extraneous variables so that they don’t effect the investigation. This means experiments can show cause and effect.

No caffeine drinks for 12 hours previously Quiet environment used Independent Variable Caffeine influences Dependent Variable Number of words recalled Time of day All tested at 9 am No caffeine drinks for 12 hours previously These are controls Tea/ Coffee Quiet environment used Noise

Task Booklet pg. 11-18