What is forgetfulness and why do we forget important things?
What did you have dinner last night? When was the last time you cried? What did you do on the morning of April 15, 2008? How did you celebrate your third birthday? Surely you have not been able to answer all these questions. What is the reason for this kind of forgetting?
Let's see what are the neuropsychological mechanisms that explain this phenomenon.
What is forgetting?
The memories are not permanent, since they are kept in a tissue that changes continuously in which some neurons die and certain connections change or weaken. This supposes not only that we can lose the accessibility of the stored information, but also its availability in our cognitive system.
What is the difference between the two concepts? According to Endel Tulving, accessibility refers to the ease with which a stored memory can be recovered at a certain time, while availability refers to the presence or not of a trace in the memory store.
Thus, an experience may seem lost in its entirety only because there is no adequate recovery key that evokes the memory. This would imply an inaccessibility of the information at the time of recovery, but not necessarily a loss of availability, so it could be recovered at another time.
Types of forgetting
Attending to the studies carried out on memory, two types of forgetting are distinguished: intentional forgetting and incidental forgetting . The first undertakes processes or behaviors that intentionally decrease accessibility with some purpose, while the second occurs without the intention of forgetting. This article will focus on the latter, showing some factors that encourage and diminish it.
Factors that encourage incidental forgetting
Now, what factors influence when we simply forget some relevant data?
1. Passage of time
The curve of oblivion (described by Ebbinghaus), shows a logarithmic decrease in memory retention based on elapsed time (known as footprint decay). That is, as time passes we remember less information.
However, it is impossible to control factors such as the recall of memories or the storage of new experiences, which generates interferences, being difficult to demonstrate empirically the effect of time per se.
Other factors to consider are the fluctuations of the context and the interference.
2. Context fluctuations
When the incidental context of recovery does not correspond to the context present during coding , forgetfulness is more likely. Over time, contextual changes are, in general, greater, since the world changes and so do we. An example is the case of childhood amnesia, which refers to the difficulty that most people have to remember the first years of life.
One possible cause is that children experience things very differently from the adults they become in, things seem relatively larger in childhood. (However, the maturational process in which they find themselves must be taken into account, since they have not yet developed the brain as an adult).
The interference refers to the difficulty of recovering similar stored strokes. We are able to remember with greater ease and for more time experiences that are unique and easily differentiable. Thus, sticking to routines makes life remember less .
Interference becomes greater when the key that allowed access to the object memory trace is associated with additional memories, because several items compete with the objective of accessing consciousness (competition assumption). That is, if we store information similar to the consolidated one, it is more difficult to access it. For example, the memory of a summer. We will remember more easily the year we visited the village of our neighbor (unique experience) than the summer in which we went to ours, since in the second case, going every year, it will be difficult to discern what happened specifically in each one.
4. Presentation of part of the keys of the set
When part of a set of items is presented, the ability to remember the remaining items of the group is weakened.
This is due to exposure to one or more competing items , which aggravates the problems we find to recover a certain objective memory. The logic, following the situation of interference described above, is as follows: if the presentation of some items of the set strengthens the association of those items with the key, the strengthened items will produce greater competition during the recovery of the items not presented and will damage the memory.
For example, when we do not remember a word (we have it "on the tip of the tongue") it is not beneficial for our acquaintances to offer us a wide list of terms since they will promote the accessibility of the same, but not the word in question .
A paradoxical characteristic of human memory is that the very fact of remembering causes forgetfulness. The intentional recovery of an experience produces an effect on memory.
If memories recover periodically, their resistance to oblivion increases . However, we must be cautious about what is being recovered, because if we recover the experience on several occasions, perhaps we are evoking the memory of what we have recovered previously (with its own context and details), and not the original situation.
This means that the more often we recover an experience, the more recovery events will exist in our memory. As long as the information retrieved is more and more accurate and complete, the process will improve recall. However, if the memories are incomplete or inaccurate (due to interferences made during attempts to reconstruct the event), what we remember might not be what originally happened.
For example, when reviewing selectively only some subjects that enter for an examination (due to lack of time), the material not reviewed will be damaged, especially if it is related to the revised one.
What factors stop incidental forgetting?
Jost's Law says that if two memories are equally strong at a certain time, the oldest will be more durable and will be forgotten more slowly. Thus, it is widely accepted that, in principle, the new strokes are more vulnerable until little by little they are recorded in the memory through the consolidation process.
Types of consolidation
There are two types of consolidation: synaptic consolidation and systematic . The first shows that the imprint of the experience needs time to consolidate (hours / days ...) because it requires structural changes in the synaptic connections between neurons. In this way, until they have been produced, the memory is vulnerable.
The second hypothesis is that the hippocampus is necessary for memory storage and subsequent recovery (as it constantly reactivates the brain areas involved in the initial experience), but its contribution decreases over time until the moment in which the cortex itself is capable of recovering information. Until the memory fails to be independent of the hippocampus, it is more vulnerable to oblivion.
- Baddeley, A., Eysenck, M.W., & Anderson, M.C. (2010). Memory. Alliance.