Research MethodsSteps in Psychological ResearchExperimental DesignVariables – IV and DVOperational HypothesisExtraneous VariablesParticipants

Study Design Dot Points- experimental research: construction of research

hypotheses; identification of operational independent and dependent variables; identification of extraneous and potential confounding variables including individual participant differences, order effects, experimenter effect, placebo effects; ways of minimising confounding and extraneous variables including type of experiment, counterbalancing, single and double blind procedures, placebos; evaluation of different types of experimental research designs including independent-groups, matched-participants, repeated-measures; reporting conventions

Steps in Psychological ResearchScientific research involves using a research

method to collect information relating to a particular research area, then organising the results and reaching conclusions from that data

This is often planned and conducted in a particular way known as the scientific method

If the scientific method is not followed then it is difficult to reach valid conclusions regarding your research

1. Identify the research problemThe first step is to identify an area of

interest or a topic to be researched

A literature search will aid the researcher in determining what prior research has been conducted and what areas of the topic might need further research

This will allow the researcher to propose a research question which can be investigated and researched

2. Formulate a hypothesisA hypothesis is a testable

prediction of the relationship between two or more variables

It is usually based in prior knowledge of the area or topic to be researched and is formulated prior to the conduction of the research

3. Design the method The method needs to be designed based around the

hypothesis and what you determine as being the best way to test it

The research method will depend upon the topic and the hypothesis

It must be decided what participants will be studies, how many, and how they will be allocated to the study

The method to collect data also needs to be determined

Ethical considerations also need to be taken into account here

4. Collect the dataThis step involves collecting the data

which will be used to test the hypothesis

Psychology uses many different data collection methods such as questionnaires, observations, interviews, and physiological recordings to obtain data

Once again the method of data collection will depend upon the study

5. Analysing the dataThe data then needs to be

collated and organised into a meaningful display

This may involve collating large amounts of data and summarising into tables, graphs etc in order to better determine if the hypothesis is supported or rejected based upon the results

6. Interpret the dataThe data then needs to be interpreted

and explained so conclusions can be formed

A conclusion is a judgement about what the results of an investigation mean

Statistical tests can be used to help determine the significance of the results and whether the hypothesis is supported or rejected based upon the research

7. Report the findingsThe final step is to report the findings

to others who may be interested in the research

A strict format is followed to report the findings of psychological research

This step is important as it allows others to examine the validity of your research and allow them to replicate the study if needed

The first thing I would like you to do now is to create a flow-chart demonstrating how psychological research is conducted

Make sure you include some important points about each step and why they are important

Experimental DesignAn experiment is used to test a cause-

effect relationship between two or more variables

Research can be conducted to determine if one variable (a possible cause) has an effect on another variable

Write down two examples of where you think there could be a cause-effect relationship between two variables

VariablesA variable is any factor which can

change or vary over timeBelow write down 5 examples of

a variable – it can be anything which varies over time

Independent VariableThe independent variable (IV) is

the variable in the research which is manipulated or changed by the researcher to measure its affects on the participants responses or results

It is called the independent variable because the researcher can independently vary it is some way during the research

Dependent VariableThe dependent variable (DV) shows any

effects of the IV and is expected to change as a result of manipulation of the IV

It is called the dependent variable because whether or not it will change and the way in which it changes is dependent on the IV

In the cause-effect relationship, the IV is the possible cause, while changes in the DV are the possible effects

Recognising the IV and the DVIt is important that you are able

to recognise the IV and the DV in particular scenarios

Using the following research question, determine the IV and the DV…

Does smoking marijuana affect driving performance?

Recognising the IV and the DVIn this particular scenario the IV

is whether or not the participant has smoked marijuana while the DV is the participants driving performance

Driving performance is dependent on whether or not the individual has smoked marijuana or not

Recognising the IV and DVIt is important you are able to

recognise what variable constitutes the IV and the DV in a research question

It is handy to have a memory device to enable you to remember how to recognise the IV and DV

What you wear depends on the weather

What you wear (the DV) is dependent on the weather (the IV)

WorksheetComplete the worksheet

◦Independent and Dependent Variables

◦For each of the research questions, see if you can determine the IV and the DV

IV and DVSimple experiments use one IV with two values or

levels (usually referred to as an experimental condition and a control condition)

In the experimental condition the IV is present or and tested while in the control condition the IV is removed

The control provides a comparison for the experimental condition where the IV was present

Without a control it would not be possible to determine if the IV has caused a change in the DV

Operational HypothesisAs we have previously seen, a

hypothesis is a testable prediction between two or more variables

For our research question example…

It is predicted that smoking marijuana will affect driving performance

Operational HypothesisBut how do we know the levels or

values which will be used in our variables?

The previous research hypothesis doesn’t tell us who will be studied or what values the variables will be

Operational HypothesisLooking at our research hypothesis again – It is

predicted that smoking marijuana will affect driving performance

How do we know how much marijuana is smoked, and when? How will we determine what driving performance will be measured? Who are we measuring?

An operational hypothesis expresses the research hypothesis in terms of how the experimenter will determine the presence and levels of the variables under investigation – how the experimenter is going to put the hypothesis into operation and who it will be studying

Operational HypothesisWe therefore need to operationalise our

variables – that is show how they will be in operation, as well as showing what the population is which will be studied

Variables which need to be operationalisedIV – Whether or not marijuana is smokedDV – Driving performance

We also need to determine what population we will be studying

Operational HypothesisAn example of how we could operationalise our

variables…

IV – Smoking marijuana: Smoking one joint containing 500mg of pure marijuana (not mixed with tobacco) 20 minutes before taking a driving test

DV – Driving performance: % score on the Vic Roads “Are you ready?” driving simulator

And the population…

Males aged 18-25years of age

Operational HypothesisNow we can formulate our operational

hypothesis…

It is predicted that males aged 18-25 years of age who have smoked marijuana (smoking one joint containing 500mg of pure marijuana 20 minutes before taking a driving test) will perform worse on a driving test (obtain a lower % score on the Vic Roads “Are you Road Ready?” driving simulator) compared to participants who have not smoked marijuana.

WorksheetThe best way to learn how to

create an operational hypothesis is to do it yourself

Complete the worksheet “Writing an operational hypothesis”

How can you remember what you need to include in an operational hypothesis?

A good way to remember what you need to include is to use the acronym…

I -P -O -D -

Extraneous VariablesExtraneous variables are any variable

other than the independent variable that can cause a change in the DV affect the results of the research in an unwanted way

Think back to the previous research scenario regarding smoking marijuana affecting driving performance, what could some possible extraneous variables be in this research question?

Extraneous VariablesIt is important that the influence of any

extraneous variables are minimised or eliminated

If an extraneous variable is not controlled for it can cause confusion in the results and the researcher cannot be sure if any change in the DV has come about as a result of the IV

When an extraneous variable is uncontrolled and causes confusion in the results it is referred to as a confounding variable

Extraneous VariablesFor our research question (does

smoking marijuana affect driving performance?) what are some possible extraneous variables which could cause a change in the DV?

Methods to Control Extraneous VariablesParticipant selection

Experimental design

Placebo effects (single-blind)

Experimenter effects (double-blind)

Participant SelectionWhen we conduct research we may want to

draw conclusions which are relevant to a particular group or groups of people

This group is referred to as the population

It is very rare for research to be conducted on every member of a population therefore we use a representation of that population known as the sample

Participant Selection It is important that the sample is an accurate representation of

the population

To achieve this accurate representation researchers use random sampling and stratified random sampling

Random sampling is a procedure in which every member of the population has an equal chance of being selected

Stratified random sampling involves dividing the population in sub-groups based on the value of a certain variable which may be confounding, the sample is then taken randomly from each group so as to create a sample with an equal proportion as each group exists in the population

This could be any personal variable such as age, gender, weight etc

Participant Selection For example if the population of people who did yoga in

FTG was 5000 people, then it is very unlikely that there would be 50-50 male to female

In fact (to use a generalisation) there is probably a great deal more females which means if we took a random sample it is unlikely to be a complete representation of the population

We can stratify the population so as to include equal proportions of the gender as they appear in the population

Stratified random sampling is very time consuming as you need to identify the relevant factors which need to be stratified and the proportions in the population calculated