What is forgetting in psychology?

Answer 1

Forgetting in cognitive psychology is still a process that is still the object of plenty of research.

For short term memory:

Most modern accounts hold that forgetting is caused by interference between past and new information. Some other models explain forgetting by a proces of passive deterioration of information. Both accounts can coexist, but interference seems to better explain results. One should not forget that memory and attention processes are very much linked and that the more attention is given to some information, the faster it will be encoded in memory and the better it should be recalled.

For long term memory:

Information is stored in a very complex, probably cyclical and redundent system. Failure to remember happens when one is unable to reactivate the memory circuit of a given information. Sometimes, a single cue will be enough to reactivate the associated information (thus the difference between recall and recognition).

Forgetting can also happen "in between" short and long term memory: when the information is to be encoded. This can happenonce again through interference and is more likely if the information isn't linked to any other memory circuit. Generally, the less a circuit is connected to other memorier, the less likely it is to be remembered or recalled.