Research Methods - Key Terms

Experimental Method

→ A deliberate change is made to an independent variable in order to measure its effect on the dependent variable

→ Experiments may be laboratory, field, natural or quasi 

Aim

→ A general statement of what the researcher intends to investigate, the purpose of the study 

Hypothesis

→ A clear, precise, testable statement that states the relationship between the variables to be investigated

Directional Hypothesis

→ Tends to be used when the findings of previous research studies suggest a particular outcome

→ include words such as ‘more’ or ‘less’, ‘higher’ or ‘lower’, ‘faster’ or ‘slower’

→ states the direction of the difference or relationship

Non-Directional Hypothesis

→ Tends to be used when there is no previous research or when findings from earlier studies are contradictory

→ states that there is a difference between conditions or groups of people

→ keywords are difference or affects 

Variables

→ any thing that can vary or change within and investigation

→ variables are generally used in experiments to determine if changes in one thing result in changes to another 

Independent Variable

→ Some aspect of the experimental situation that is manipulated by the researcher - or changes naturally - so the effect on the DV can be measured 

Dependent Variable

→ We measure the effect the Iv has on the DV

Operationalisation

→ clearly defining variables in terms of how they can be measured

Extraneous Variable

→ any variable, other than the independent variable, that may affect the dependent variable if it is not controlled 

Demand Characteristics

→ Any cue from the researcher or from the research situation that may be interpreted by participants as revealing the purpose of an investigation

→ This may lead to a participant changing their behaviour within the research situation

Investigator Effects

→ Any effect of the investigators behaviour (conscious or unconscious) on the research outcome

→ This may include everything from the design of the study to the selection of, and interaction with, participants during the research process

Randomisation

→ The use of chance methods (e.g. tossing a coin or random number generators) to control for the effects of bias when designing materials or deciding the order of experimental conditions 

Standardisation

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

Experimental Design

→ The different ways in which participants can be organised in relation to the experimental conditions

Independent Groups Design

→ Participants are allocated to different groups where each group represents one experimental condition

Repeated Measures

→ All participants take part in all conditions of the experiment

Matched Pairs Design

→ Pairs of participants are first matched on some variables that may affect the dependent variable

→ Then one member of the pair is assigned to condition A and the other to condition B

Random Allocation

→ Participants are allocated to conditions in an independent groups design using a random method to control for participant variables 

Counterbalancing

→ An attempt to control for the effects of order in a repeated measures design : half the participants experience the conditions in one order, and the other half in the opposite order

Laboratory Experiment

→ An experiment that takes place in a controlled environment (not necessarily a lab) within which the researcher deliberately changes the IV and records the effect on the DV, whilst maintaining strict control of extraneous variables

Field Experiments

→ An experiments that takes place in a natural setting within which the researcher deliberately changed the IV and the effect on the DV

Natural Experiment 

→ An experiment where the change in the IV is not brought about by the researcher but would have happened even if the researcher had not been there 

→ The researcher records the effects on a DV

→ May take place in a lab or in the field