(This post is an excerpt from my book Super Learning 1: The DNA of Learning)
There are two ways in which new learning can disrupt existing knowledge – and vice versa.
Let's take a closer look at them.
Retroactive interference
Retroactive interference, also called catastrophic forgetting, occurs when newly learned information interferes with the memory of previously learned information.
Experiments conducted by John McGeoch and William McDonald on retroactive interference show how learning new information can interfere with the memory of previously learned information. They found that when participants learned a list of words and then learned a new list, their ability to remember the first list was impaired. Retroactive interference can occur, for example, when you study for multiple exams close together; what you learned first may become harder to remember after studying a new topic.
Proactive interference
Proactive interference occurs when previously learned information interferes with the ability to remember or learn new information.
The more we use a mental model, the more automated it becomes: A classic example is the way most of us learned the alphabet – with an accompanying song. For many people, the song is so ingrained in their memory that they can’t tell the two apart. For example, if I have to find the 7th letter of the alphabet, I sing the alphabet song in my head. Do you do that too?
The way we remember is closely linked to the way we learned the knowledge in question and the way we apply it.
For example, it is very difficult to name every other letter of the alphabet because it:
- is not how we have learned it , and
- That's not how we use it.
Imagine learning to say the alphabet backwards. Your ability to do so will likely be greatly impaired by your ability to say it forwards. Therefore, it can also be difficult to learn and adapt to new ways of performing tasks in your work once you have learned them one way.
Strategies to minimize interference
We can derive two pieces of advice regarding catastrophic interference:
- Proactive interference: If you want to learn something thoroughly or well, it would be a bad strategy to learn to do it sloppily first in the hope that you can then “add layers”. It is therefore often a good idea that the way you learn knowledge or skills is similar to the situation in which you will use the learning, so that it becomes automatic. This is what is seen in problem-based or case-based learning.
- Retroactive interference: You should limit the amount of information you want recipients to read. This often means you will need to prioritize which information is most important, but you will also need to take into account how the information fits into the recipients' existing knowledge.