Two separate groups of participants experience two different conditions of the experiment. If there are two levels of the IV, this means all pps take part in one level of the IV only.
Repeated measures
The same pps will be used for all conditions - complete the experimental task with the IV set for condition 1 and then the same for the IV set for condition 2
Matched pairs
Where pairs of pps are matched on some variable that may affect the DV. Then, one member of each pair is assigned to Condition A and the other to Condition B
