"Memory is the thing you forget with." - journalist Alexander Chase
Can you draw a penny, front and back, including correct placement of the eight critical features? If not, is this an example of forgetting?
Not being able to recall something (a person's name, a fact, an event) may be attributed to a variety of causes. One of the most common is that the brain never encoded the information in the first place. Something heard, seen or thought about is processed in short-term memory, but is not automatically encoded in long-term memory. This explains why, when we are introduced to someone, we often can't recall his or her name minutes later. And it also accounts for the fact that, though we see and handle pennies daily, we may not have encoded their features.
Memories are first created in the hippocampus, which stores them temporarily before permanently assigning them storage sites throughout the brain. This can take minutes or hours. Nerve connections must be formed and strengthened through use. If the connections break down due to lack of use, we forget. Most things are "forgotten" because of weak encoding; in other words, the memory trace was not permanent enough to remain for a long period.
Some things are forgotten because of interference from similar information, as with repetitive experiences. For example, you might have difficulty recalling what you ate for dinner last Tuesday, especially if you eat dinner in similar circumstances almost every night. The more similar memories are in meaning and content, the more likely they are to interfere with each other. However, if last Tuesday was your birthday and you ate at a special restaurant, the memory would be distinct and not likely to be forgotten.
When we do things automatically, usually out of routine or habit, we don't have to pay conscious attention to what we are doing. As a result, we often don't remember the actions we just carried out. Common examples include: pressing the button to activate the garage door, taking our daily vitamins, putting sugar in our coffee. We can't remember because we were not consciously attending to these tasks as we performed them. (Caution: this lack of attention when performing automatic behaviors may contribute to absent-mindedness!)
Have you ever walked into a room and realized that you'd forgotten why you went in there? Forgetting can result from a change in context. What we learn in one environment is often more difficult to retrieve in another. This might explain why, when you're at the mall and run into people you've met at church, their names elude you.
We're usually better able to recall generalities about information or an event than the verbatim or specifics. We tend to fill in the gaps with "reasonable" facts or details. Over time, our memory changes as a result of this unconscious reconstruction of the event based on subsequent experiences or information. So it's not so surprising that you and your siblings often have different recollections of the same event from your past!
Similar to being unable to locate a book in the library without knowing its call number, we are sometimes unable to access information from long-term memory because we don't have the appropriate retrieval cue. Just as a fragrance or melody can bring to mind an experience from your distant past, an appropriate stimulus is needed to access any particular memory. You may have difficulty recalling an actor's name without being cued by the name of the movie in which they starred.
Weak encoding, interference, automaticity, context change and insufficient or absent retrieval cues all contribute to the phenomenon we call forgetting. By making ourselves more aware of these contributors to lapses in memory, we might be able to decrease the frequency of having to say, "I forgot!"