Research methods

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  • Created on: 20-01-19 15:01

Experimental method


Aims are developed from theories and and are general statements that describe the purpose of an investiagtion


A statement that is made at the start of a study and clearly states the relationship between variables as stated by the theory

In a Directional hypothesis the research makes clear the sort of difference that is anticipated between two conditions or two groups of people. For this reason, directional hypotheses include words like more or less, higher or lower, faster or slower etc. An example is 'People who drink SpeedUpp become more talkative than people who don't.

In a Non-directional hypothesis, it simply states that there is a difference between conditions or groups of people, but the nature of the difference is not specified. An example is 'People who don't drink SpeedUpp differ in terms of talkativeness compared with people who dont drink SpeedUpp

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Experimental method 2

IV and DV's

A researcher changes or manipulated the independent variable and records or measures the effect of this change on the dependent variable.

Levels of the IV

In order to test the effect oc the IV we need different experimental conditions.

Operationalisation of variables

when the researcher ensures that the variables being investiagted are as unfuzzy and measurable as possible

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Control of variables

Extraneous variables

any other variables, besides the IV, that might potentially interfere with the IV (or the DV) which should be controlled or removed. When possible, the researcher will identify these at the start of the study and take steps to minimise their influence.

Many extraneous variables are straightforward to control such as the age of the participants, lighting in the lab etc. These are described as 'nuisance variables' that do not vary systematically with the IV.

Confounding variables

Any variable, other than the IV, that may have affected the DV so we cannnot be sure of the true source of changes to the DV. Confounding variables vary systematically with the IV.

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Control of variables 2

Demand characteristics

Any cue from the researcher or from the research situation that may be interpreted by the partcipants as reavealing the purpose of the investigation. This may lead to a participant changing their behaviour within the resarch situation.

They may behave in a way they think is expected and over-perform to please the experimenter (the 'please-U effect' or they may deliberately underperform to sabotage the results of the study (the 'Screw-U effect')

Investigator effects

Any effect of the investigator's behaviour (conscious or unconscious) on the research outcome (the DV). This may include everything from the design of the study to the selection of, and interaction with, participants during th research proccess.

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Control of variables 3


the use of chance in order to control for the effects of bias when designing materials and deciding the order of conditions.


Using exactly the same formalised procedures and instructions for all participants in a research study.

This includes standardised instruction that are read to each participant. Such standardisation also means that non-standardised changes in procedure do not act as extraneous variables

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