遗忘是记忆中的一个特殊功能。人类的感觉器官接收到的信息非常多。而遗忘使得人只保留重要的、相关的信息，减轻大脑空间压力，有积极意义。一个事件会否被遗忘，跟与其联系之事件的数目、它所唤起情感和时间，还有和身体状态有关。但普遍认为，相对于记忆是主动，遗忘是被动的。就是说，人能够主动选择记住某件事，而不能选择去忘记某件事。为了避免将重要的信息被遗忘，人们通常的做法是：复习。在保罗康纳顿的研究中，他认为有七种不同的遗忘形式，分别是：强制消除性遗忘，指向性遗忘，制造新身份性遗忘，结构失忆性遗忘，废止性遗忘，计划忘却性遗忘和受辱性遗忘。

Forgetting is the apparent loss or modification of information already encoded and stored in an individual's long term memory. It is a spontaneous or gradual process in which old memories are unable to be recalled from memory storage. Forgetting also helps to reconcile the storage of new information with old knowledge. Problems with remembering, learning and retaining new information are a few of the most common complaints of older adults. Memory performance is usually related to the active functioning of three stages. These three stages are encoding, storage and retrieval. Many different factors influence the actual process of forgetting. An example of one of these factors could be the amount of time the new information is stored in the memory. Events involved with forgetting can happen either before or after the actual memory process. The amount of time the information is stored in the memory, depending on the minutes hours or even days, can increase or decrease depending on how well the information is encoded. Studies show that retention improves with increased rehearsal. This improvement occurs because rehearsal helps to transfer information into long term memory - practise makes perfect.