While we may not know much about why we forget, we know more about what kinds of things we are likely to forget.

For example, I have repeatedly made the point in this lecture that the more meaning something has, the better it is retained. Conversely, meaningless data such as nonsense words are lost quickly, with only about 35% being retained longer than about 24 hours.

Four main processes are known to be important in forgetting:

Encoding failure: unless something is given meaning, it is difficult to connect it to the meaning map that is memory. When it cannot be located, it will be much harder to find and retrieve it. Just like when you hide one match in a match box, finding the one match is a lot easier if it is a different colour than if it is identical to all the rest of the matches in the box.

Traces decay: It may be that the structural features of the memory trace are more easily lost if the information lacks meaning (e.g. is more deeply encoded)

Retrieval failure: finding something once you have stored it is a common reason for poor recall. (See Encoding above) Retrieval failure can be as simple as forgetting where you put the information or more complicated.

The most common reason for forgetting is inadequate encoding or even inattention at the time of encoding (see slide 4)

Summary:Forgetting is common and normal. Often we “forget” because of inattention to the data, which isn’t properly encoded.