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Monday, September 26, 2011

How do we remember?

If we start from the idea that cognitive system receives sensory and environmental stimulation every second, of every minute, of every hour of the day, then we have a rough idea of how much information our brain processes continuously, even during sleep.

In comparison, if we keep a computer turn on with continuous data analysis during, let's say... 20 years, there will be a moment, regardless of storage capacity and RAM memory, when it will have to reset and  probably lose some data processing.

But the brain in general, unless there is a neurological condition, or a poor diet or as a result of a stroke, can not afford to lose data. However, everyday conditions as stress or lack of attention motivated can erase data, even two seconds of having access to the information. Who has not been forgotten a phone number?, or just forget why you  got up to go to another room to take some object?.

It seems that in general there should be a error margin on recovered information because sometimes we can only have access to pieces of information and some other, you get the information by association.

But brain, has also an application called cognitive economy, and it's the way to streamline the system and make it capable to work with minimal information and help it to relate with other nodes of information. In this sense it's possible to group events, for example, there is no need to remember all the information about a topic, because it can be related to what is said or heard. Let's say a list all the objects found in an office or a bedroom. Usually we don't mix information from other categories, such as mosquitoes or green elves, unless that's part of the environment (Chen, Loftus, Lin, He, Chen Li, Xue, Lu and Dong, 2010).

Personally my favorite example about this application is: we never expect to mix dirty socks in the drawer of clean spoons.

At this sense, the way some people have explained the process, it's saying that memory is distributed in volumes of an encyclopedia, where each memory has a place within the private library, the way the volumes are located and how they are classified is defined personally. The same memory can be in a classification for a person but in a different place for someone else even if they have experienced the exact same event (Sagan, 2001).

That is why understanding the cognitive economy, allows the system to use information efficiently, and all this knowledge has led to the development of electronic systems with much more rapid data processing and order.

But then, it seems logical that there are different stages or processes in memory, because we can talk about a consolidated memory where we can find aspects of personal life or learning that we never forget, like riding a bicycle or driving a car (when you have the ability) and on the other hand, there are aspects of memory in the here and now.

There is a complete group of research about long-term memory, some call it an episodic, and on the other hand, researches describe a memory of here and now, it's called short-term, but in general is known as working memory (Contreras Ruiz and Cansino, 2005, Burin and Duarte, 2005).

The long-term memory or episodic, from the neurological point of view requires morphological and functional changes in synaptic transmission, which in turn requires the open and closed gene activation and synthesis of proteins that allow the flourishing of synaptic buttons (Ruiz Contreras and Cansino, 2005).

These memories are rooted, which can be very personal issues or behaviors that are performed automatically, also known as habits.

When someone asks: what's your name?, it's not required to open the system information to find the answer, you automatically will respond my name is ...

But for making this  possible, information must be consolidated, that's why repetition is an important element in the process, but not only in linguistic form, since it can be involved more than one sensory system. How many times have you tasted an orange  and knew without doubt, that it was an orange?, The relationship of the word orange is given from the taste, smell, shape, color, texture, size ... the relation of all that with the word is what is known as orange.

The short-term memory or operational work is what we use routinely when someone gives us information on how to get to a place or just for specific instructions. This information is much more volatile than long-term memory; it depends of the attention to keep it in the system.

This memory in general is linked with language, as it tries to retain information through words even when the information is obtained from any other sensory modality. In addition, it looks more related   to closed genes since it depends on the holding capacity of each individual (Morgado Bernal, 2005).

Moreover, most models of working memory separate two types of sources: active mechanism  processing,  that are managed by attentional resources, for example, pay attention to something specific, and  there is  in addition,  passive mechanisms , where there is a clear intention to remember. Although, these passive forms may arise through the association of ideas or stimuli.

It is also thought, that the mechanisms are primarily linguistic processing, as when trying to remember something we read or hear, but it can be visual as one of the main sources of information and also poses a spatial mechanism, which gives us the ability to make a movement.

In this sense the brain areas involved range from visual, motor and language in all its forms (Burin and Duarte, 2005).

On the other hand, some researchers have tried to understand the mechanism of consolidation, as some tasks seem to give priority to a serial system, where information must have some specific order, hence the series should be ordered and sequenced in a particular way, an example of this is the multiplication tables, while other de tasks does not require order, but if the association (Sackur and Dehaene, 2009).

There is a model called dual categorization, where both processes can be used depending on the requirements of the task (Glöckner and Witteman, 2009). This may occur when someone needs to make decisions using insufficient information.

But once the information consolidated, it is necessary to recover it, otherwise it's not possible to know if it exists or if we saved it correctly. Although usually it's seen as a part of the memory, actually this process uses different areas of the brain and specific mechanisms. Basically it is defined as the process of extracting information stored in memory in response to a task (St. Clair Thompson, 2010), but memories doesn't come specifically by need, because sometimes they come at once, linked with other topics.

Areas that are in charge of this process are the hippocampus and prefrontal cortex. During the recapitulation of events  our  hippocampus receives information from the neocortex and sends efferent projections, which suggests that the hippocampus is the director who receives and seeks; provides an order  to all information and at the end decides  the output source, which can be a word, a movement or shape (Ruiz Contreras and Cansino, 2005).

The process will let us remember only the information that we will  use steadily, otherwise will be forgotten, except in the case of information linked  with emotion, which explains the flashbacks, as in the case of people who have suffered any trauma and gives as a result a memory that is virtually indelible. And on the other hand, a memory problem can also be lack of consolidation or retention of information, such as when studying for hours for an important exam and recovery time is simply not capable of displaying all information.

These two examples are just a little part of the challenge trying to understand the whole process of memory, because laboratory studies are far from emulating the multi-level activity that takes place daily in every brain, and how it uses and manage information. Hence the process of knowledge-based on economy provides some order to the amount of information that sometimes is handled.

That is why information apparently is grouped in related areas, and all information on how to write is in a drawer and the information used to get home is in a different drawer. But it is also true that sometimes distant areas are related, because this allows creativity and problem solving (Weimer and Palermo, 1974).

But, please, you don't need to worry, because your brain works 24 hours a day for 7 days a week, even while you sleep, deleting unnecessary information which allows more space for more events and this makes  possible  our function in the hectic and fast world of information. On the other hand, the brain has learned to use tools that are designed for those who feel that the memory is expandable.

Yes, there is a cult for all the tools, applications and toys, every day there is a new device or an application for everything imaginable and unimaginable, but we can't  forget that those gadgets depend on batteries, connections and servers with a memory finite, and the disaster is massive when those systems are violated or space is not enough. In contrast, your brain can always expand your ability to learn strategies that will make the process easier and only asks for food, rest, environmental stimulation and a little of socialization.


Burin, D. y Duarte, AD. (2005) Efectos del envejecimiento en el ejecutivo central en la memoria de trabajo. Revista Argentina de Neuropsicología. 6. 1-11.

Chen, C., Loftus, E., Lin, C., He, Q., Chen, C., Li, H., Xue, G., Lu, Z., and  Dong, Q. (2010) Individual differences in false memory from misinformation: Cognitive factors. Memory. 18 (5) 543-555.

Glöckner, A. and Witteman, C.  (2009) Beyond dual- processes model: A categorization of processes underlying intuitive judgment and decision making. Thinking and reasoning. 16 (1) 1-25.

Morgado Bernal, I. (2005) Psicobiología del aprendizaje y la memoria. Cuadernos de comunicación e información. 10 (2) 221-233.

Ruiz Contreras, A. y Cansino, S. (2005) Neurofisiología de la interacción entre la atención y la memoria episódica: revisión de estudios en modalidad visual. Rev. Neurol. 41 (12) 733-743.

Sackur, J., and  Dehaene, S. (2009) The cognitive architecture for chaining of two mental operations. Cognition. 111. 187-211.

Sagan, C. (2001) Cosmos. Editorial Planeta. España.

St. Clair Thompson, HL. (2010) Backwards digital recall: A measure of short-term memory or working memory?. European Journal of Cognitive Psychology. 22 (2) 286- 296.

Weimer, W. and Palermo, DS. (1974) Cognition and the symbolic processes. Lawrence Erlbaum Associates. USA.

3D image: Juan Conde Tovany

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