experimental design

• independent group design

  • the participants only perform in one condition of the iv
  • a strength = no order effects and participants are less likely to guess the aim of the study so reduced demand characteristics
  • limitation = no control over participant variables - the different abilities of participants in various conditions can cause changes to the dv and you need more participants then other designs to gather the same amount of data
  • to solve limitation you can use random allocation ensures each participant has the same chance of being in one condition of the iv as another
• Repeated measures

  -          The same participants take part in all conditions of the iv

  -          hey strength is that this design eliminates participant variables a few participants all needed therefore it is less time consuming

  -          however a limitation of this design is order effects- participants boredom may mean they don’t do as well the second time on a task

  -          to reduce older effects you can use counterbalancing which is when half of the participants do conditions in one order and the other half do it in an opposite order

   

   
• matched pairs

  -          is when passive participants are first matched on some variables that is predicted to have an effect on the dv then one member of each pair does one condition and the other does another

  -          the strength = no order effects and demand characteristics of less of a problem

  -          limitations= time consuming and expensive to match participants . To make these matches I large pool of potential participants is also needed which is hard to get it's also difficult to know which variables are appropriate for the participants to be matched on.