P - majority of evidence comes from lab based research
E - Mcgoech and Mcdonald lacks ecological validity - don't normally learn synonyms or antonyms lists on a day to day life
E - PPT often have only a short time between learning the new pieces of info - whole experience could be done in over a hour which doesn't reflect rea life learning
L - therefor research used to support interference theory lacks ecological validity
P - support for real life applications
E - baddely and hitch - rugby players remember team names they had played during the season
E -results = recall did not depend on how long ago matches too place it was how many games they had played
L - therefor interference does have some external validity as we can see it occurring in every day life
P - interference can be overcome by using cues
E - tulving + ptoska gave ppt lists of words to remember and organize into categories
E - recall of list was 70% but fell down with each new list, but when given cues recall rose back up to 70%
L -this shows interference causes just a temporary loss of access to material still in LTM not a permanant loss