The interference explanation for forgetting has two models which are proactive interference and retroactive interference.

Proactive interference

Proactive interference is when an old memory interferes with something a person is trying to remember now.

Retroactive interference

Retroactive interference is when a new memory interferes with old memories.


Research into interference as an explanation for forgetting goes as far back as 1924 when Jenkins and Dallenbach asked group members to learn “nonsense” syllables through the use of Trigrams. Trigrams are used to study memory and are combinations of three letters which do not form any real worlds e.g. lep, tes or hal.
Participants were tasked with recalling the trigrams after time periods of one, two, four and eight hours. Some participants slept during these time periods while others remained awake. The results found that participants who slept were able to better recall the trigrams than those who remained awake. This appeared to support interference theories as researchers assumed recall for those who remained awake was poorer because of their mental activities while awake affecting their ability to recall the trigrams.

Weakness/Criticisms Of Interference Theories

One criticism of this study and its findings is that sleep could have actually helped consolidate memories and be a confounding variable which is affecting results. Therefore memory recall being poorer when awake may not necessarily be due to interference affecting memory but rather sleep improving recall and promoting results which were better for that set of participants.

Ellenbogen et al 2009 – The Sleeping Brain’sInfluence On Verbal Memory

Ellenbogen et al conducted a study to see if past memories would be affected by the learning of new memories through the use of word pairs. Participants were asked to learn a list of word pairs known as the A-B lists. Recall was tested after a time lapse of 12 hours.

10 minutes after learning the A-B lists, participants were tasked with learning a second list of word pairs called A-C lists. The first word (A) was the same as the A-B list however the words of the pair (C) was different.
After another period of 10 minutes participants were asked to recall the A-B lists they initially learnt. The results found that participants scored lower recalling the A-B list and concluded that the new A-C list had interfered with the memories associated with the A-B list supporting interference explanations for forgetting.

Practical Applications Of Interference Explanations Of Memory


  • Interference as an explanation for memory teaches us that learning two things which are very similar is difficult and easily confused when done around the same time. The practical application here is that when we are learning concepts which may be similar, it is best to learn them at separate times so they do not become confused with one another in memory.


  • It is difficult to know for certain whether there will be conflict in learning prior to learning something and whether they are similar enough to interfere with one another. Therefore knowing exactly where the line is drawn to separate information from being “too similar for learning” at the same time is difficult. Research into encoding within memory may suggest this could be when something sounds acoustically similar or has similar meanings potentially.

How to reference/cite this information:

The interference explanation of forgetting –


Are you sure you don't want free resources for psychology?

There's no catch.

Why not join the mailing list for free resources? Theres no catch and its all completely free! Theres no spam either and we don't share your email with anyone - guarunteed.

100% secure - No Spam guaruntee.

Are You Studying Or Teaching GCSE Psychology?!

Enter Your Email Address & I'll Send You Free Resources For All The Exam Boards! (AQA, Edexcel, OCR and WJEC)