Research Methods

What is an experiment ?

• an experiment is where there is an independent variable that is changed so that an affect on the dependent variable can be observed

• They aim to establish a cause and effect relationship - where the IV causes the DV results

• To establish a cause and effect relationship it would have to be ensured that nothing other than the IV has an impact on the DV

What are the types of experiments ?

• laboratory

• field

• natural

• quasi

what is a condition ?

A condition is a specific setting, treatment of a variation of an independent variable that a researcher presents to a group of participants

E.g. there is a study that tests whether background noises affects test scores - independent variable is the noise level - the conditions are silence and moderate noise

What are laboratory experiments ?

• An experiment that takes place in a controlled environment within which the researcher manipulates the IV and records the effect on the DV, whilst maintaining strict controls of extraneous variables.

• People are randomly allocated to a condition

• Participants will know if they’re in the study

What is a field experiment ?

• an experiment that takes place in a natural setting within which the researcher manipulates the IV and records the effect on the DV

• The IV is still manipulated by the experimenter and the DV measured

• Participants are often unaware they are in research

• E.g. researchers were interested in whether a member of public would help a man who slipped if he was dressed as a homeless one or a business man

What’s a natural experiment ?

• An experiment where the change in the IV is not brought about by the researcher and would’ve happened even if the researcher had not been there. The researcher records the effect on a DV they have decided on

• The IV is natural not necessarily the setting

• E.g. studying before and after a natural disaster

• Participants are often unaware they are taking part

• E.g. researchers investigated whether children on a remote island would be more aggressive after they had a tv installed - condition 1 = no tv - condition 2 = tv

What’s a quasi experiment ?

• A study that is almost an experiment but lacks key ingredients. The IV has not been determined by anyone (the researcher or any other person) - the variables simple exists such as being young or old.

• in a lab or in a real life setting - its key feature is it is not possible to randomly allocate participants to a condition

• so participants are automatically assigned to a particular condition due to a characteristic - like gender

• the characteristic of them doesn’t change e.g. sex is set so they can only take part in one condition

• E.g. a study compares people with depression to those without it