Memory formation is the most fascinating cognitive process. The evolutionary significance of forming memories was to record past experiences to avoid unpleasant encounters and potential threats to one’s survival. Hence, the elementary memory processes are common to all the species but in humans, it takes up a rather complex role and manifests diverse higher-order functions. Human memory could be equated to the working of a supercomputer. Just as the computer takes up the relevant information, processes it, and stores it for further use, the human memory also selectively attends to the information that holds personal relevance, actively works upon it, and makes it available as and when needed. RAM is to the short-term memory as ROM is to the long-term memory. STM stores information for a relatively short duration and unless is worked upon doesn’t make its way to the LTM. The process of memory formation isn’t as simple as it sounds. Various parts of the brain work in unison to form consolidated memories rather than discrete bits of information. The cerebellum takes charge of implicit memories while the amygdala works upon the memories that have a strong emotional basis. The prefrontal cortex holds the STM while the consolidation of memory takes place within the hippocampus. The information is processed at various levels while a memory is formed in the brain. These levels have been discussed below-
- Sensory memory- It is the information that is incident on our senses at all times. We attend to unlimited stimuli every second of the day that gets registered in our sensory memory. Two types of sensory memory are Iconic and Echoic memory. The former represents the memory for visual stimuli whereas the later represents the memory for auditory stimuli. The duration upto which iconic memory lasts in the sensory store is 1 second whereas this duration for echoic memory is 4 seconds. If left unattended, the information is lost and cannot be processed further.
- Short term memory (STM)- It holds up information that is passed on from the sensory memory. The capacity of the STM to hold information is limited i.e. 土7 units (George Miller’s magic number). This capacity could be enhanced by a technique known as ‘Chunking’. The duration upto which information will last in the STM is 30 seconds. Usually information is retained in the STM by means of continuous repetitions. This phenomenon is known as Maintenance Rehearsal. E.g.- Repeating a phone number out loud until you dial it but forget it once it is of no use.
- Long term memory (LTM)- Information could be passed on from the STM to the LTM by means of Elaborative Rehearsal, wherein, we try to understand the meaning and structure of the information that is presented to us at a deeper level. Such information is rarely forgotten and could be accessed as and when required. Hence, LTM could be called a storehouse where an unlimited amount of information can be stored permanently. LTM could be categorised further keeping in view the type of information it holds-
- Declarative memory, also known as explicit memory, is the memory of conscious facts and concepts. It is further subdivided into Episodic and Semantic Memory.
- Episodic memory is the memory of specific events that hold relevance in one’s life. E.g. recalling your 18th birthday.
- Semantic memory is the memory of facts, meaning, concept and knowledge about the external world. E.g. recalling a chapter in your textbook.
- Procedural memory is the memory of skills that we have been trained to perform. This memory is part of our unconscious, hence it is known as the implicit memory. E.g. swimming, driving, painting etc.
It needs to be kept in mind that the process of memory formation is a constructive rather than a reproductive process. As humans, we tend to actively work upon the memories that are stored in our minds as a result of which the output could be very different from the input. This forms the basis of False memory. An example of this is the eyewitness testimony, wherein, a person’s statement is prone to be inaccurate than the actual incident.
Despite all the nuances, the lapses in memory formation aren’t uncommon. Due to certain organic causes or injuries to the brain, the process of memory formation could be hampered. As a person advances in age, it is common to experience minor forgetfulness. It is only when it becomes more frequent and takes an extreme form that a person becomes vulnerable to conditions like Dementia and Alzheimer’s etc. Hence, it’s extremely important to exercise your brain muscles so that it doesn’t rust out. Making use of memory aids and playing mind games can substantially enhance brain power. It’s important to know the science behind the memory processes to efficiently use them to one’s benefit.
-Smriti Saini
