6.7.2. Forgetting due to Interference

If forgetting is not due to trace decay then why does it take place? A theory of forgetting that has perhaps been the most influential one is the interference theory which suggests that forgetting is due to interference between various information that the memory store contains. This theory assumes that learning and memorising involve forming associations between items and once acquired, these associations remain intact in the memory. People keep acquiring numerous such associations and each of these rests independently without any mutual conflict. However, interference comes about at a time of retrieval when these various sets of associations compete with each other for retrieval.

Interference theory explains forgetting as a result of different pieces of information interfering with each other when we try to retrieve them. When you learn something new, it creates connections in your memory. However, when trying to recall this newly learned information, other memories can compete for retrieval, leading to forgetfulness. For example, if you have learned two lists of words, the words from one list can interfere with your ability to recall the other list when trying to remember.

Imagine you are trying to remember the names of two friends, Tom and Jerry. If you met a lot of other people named Tom recently, that might interfere with your ability to recall Jerry's name. The more similar names you encounter, the more likely they interfere, just like a crowded room where many voices make it difficult to hear one person speaking.

There are at least two kinds of interferences that may result in forgetting. Interference can be proactive (forward moving) which means what you have learnt earlier interferes with the recall of your subsequent learning or retroactive (backward moving) which refers to difficulty in recalling what you have learnt earlier because of learning new material.

Proactive interference occurs when old memories prevent you from learning or recalling new information. For example, if you learned Spanish first and then tried to learn French, your knowledge of Spanish may interfere with your ability to remember new French words. Conversely, retroactive interference happens when new information disrupts your recall of previously learned information. Using the same analogy, if you learn French and then forget some words from Spanish because you're now focused on the French vocabulary.

Think of proactive interference like an old tune that's stuck in your head, making it hard to learn a new song's lyrics. Retroactive interference, on the other hand, is like learning a new dance that makes you forget the steps to an old dance you once mastered.

A typical experimental design that is used to demonstrate proactive and retroactive interference has been presented in Table 6.1. Participants learn list A and then learn list B, followed by recalling either A or B to show how previous learning can impact memory retrieval.

In experiments to test interference theory, participants are often split into two groups. One group learns a list of items (List A), followed by another list (List B). When they are asked to recall List A, the second list can interfere with their memory of List A items. This control group, who does not learn List B until after recalling List A, shows less interference, demonstrating how previous learning can impact memory retrieval.

Consider an athlete switching from one sport to another. If a soccer player starts playing basketball, their muscle memory for soccer may interfere with learning new movements for basketball. The interference between the two sports can make it difficult for the player to recall the right techniques, just as it would in a memory experiment.

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