Experimental Designs

HideShow resource information
  • Created by: leah
  • Created on: 02-06-13 14:13

Independent Groups

No order effects because people only take part in one condition also often the same material can be used for both conditions, participents cant work out the aim of the study because they only take part in one condition meaning no demand characteristics however there are participent varibales in the two conditions so that may be why the results are different and you need more people for the study. In Independent groupds there are different groups in each condition and groups are decided though random allocation

1 of 8

Repeated Measures

There are the same group in each condition the advantage to this is there are no participent variables you need less people to get more results also its the cheapest design however there are order effects people have to do 2 tasks but can counterbalence and participents may work out the aim as they take part in both conditions meaning demand characteristics

2 of 8

matched pairs

there are different groups in each condition but matched for different characteristics like age gender and i.q participent variables are reduced there are no oder effects but matching is difficult and time consuming and its not always successful also its expensive and some participent variables are still present

3 of 8

Order Effects

When a participent does an experiment twice, the second time they do the experiment thet may get bored or tired and so do worse the second time or get better because they have practice

counterbalencing- dealing with order effect

here half the group do one condition first (condition A) and then do the other (condition B) and the other half do condition b first and condition a second. then the order effects will be equal in both groups.

4 of 8

demand characteristics and participent variables

Demand Characteristics:These are features of an experiment that lead the researcher to guessing what an experiment is about and changing behaviour to fit in with this

Participent Variables These are the Differences between participents in terms of for examples, how intelligent, how tires ther are or how interested/motivated thet are when doing an experiment

5 of 8

Standardised Procedures In Experiments

An experiment is a carefully organised procudure which uses a standardised procedure.

Sradardised Procedures; A set order of carrting out a study that is applied to all participents in the same way the use of standardised procedure makes the research unbiased and means all participents experience the same instructions

instructions information is either said to the participents or its written down and given to them. All instructions to participents have 3 parts

Breif: This is what's said to the participents to get them to take part in the study it contains eithical information such as consent right to with draw and confirdentiality

standardised instructions these are clear instructions about what the participents have to do in the experiment

Debreif: This explains the study so they know what the aim is, ethical issues are told to the participents again so they have the chance to withdraw data if they are unhappy.

6 of 8


This is making sure that there are no biases in the procedure. Randomisation is a method used to ensure this

Using the chance method to produce an order for the procedure i.e this might be used when the experimenter has selected 20 words of equal diffculty and they have to decide what order they should be presented to participents. All the 20 words are put into a hat and the order they are chosen out of the hat is the order they will be on the list. This means each word has equal chance of being selected first and the experimenter left the order of the words to chance

7 of 8


Experiment:This is a method which is scientific and uses a controlled approach to finding out about human behaviour

Natural setting: Higher ecological validity- experiment is in a real setting such as in the street

Controlled lab experiment: Low ecological validity- the experiment is conducted in a laboratory

Ecological Validity: The results from an investigation can be said to apply to real-life behaviour. they are an accurate account of behaviour in the real world

The problem with conducting research in a controlled laboratory is it can have low ecological validity so results are not applicable to real human behaviour. The problem with conducting research in a natural setting is that you have less control over Extraneous variables because its more natural but has a high ecological validity Reasearchers must carry out their research objectilvey meaning they collect information about human behaviour without their feelings or opinions effecting the interpretation

8 of 8


No comments have yet been made

Similar Psychology resources:

See all Psychology resources »See all Research methods and ethics resources »