Proposed that forgetting occurs when 2 pieces of information are in conflict with each other.
One memory blocks another causing one or more memories to become distorted.
Information that has reached the LTM memory store is considered to be permanent, but interference can result in us having trouble locating that memory - which can be experienced as forgetting.
Proactive and retroactive interference are thought to be more likely to occur when the memories are similar.
For example, students who study similar subjects at the same time often experience interference. French and Spanish are similar types of material which makes interference more likely.
Participants experienced 2 different difficulties in remembering.
In some cases, participants struggled to remember earlier adverts (retroactive interference). In other cases, participants had problems remembering the late adverts that were shown (proactive interference).
This effect was greater when the adverts were similar - i.e. adverts were for identical products but different brands (competitive interference)
A limitation of the interference explanation of forgetting is presented by Tulving and Pstoka, who showed how the presence of cues can overcome the effects of interference.
Participants in their study were given 5 lists of 24 words to learn. Each word, on each list, could be placed in one of 6 categories (which weren't explicitly stated but where assumed to be obvious).
This suggests that information hadn't suffered from interference, rather it was available in the LTM but not accessible.
The information was present in the LTM but couldn't be retrieved without the aid of a cue (the category)
In real life, this can be applied to the use of cues when revising to enable individuals to access memories of topics/concepts, and overcome the effects of interference.
Results showed that accurate recall didn't depend on how long ago the matches took place. But what was more important was the number of games they'd played in the meantime.
The players who'd played the most games forgot proportionally more games than those who'd played fewer games due to injury.
Baddeley and Hitch concluded this was the result of retroactive interference, as the learning of new info (new team names) interfered with the memory of old info (earlier team names)
This shows that the interference explanation has applications to everyday situations, thus increasing the ecological validity of the explanation.