The capacity of human beings to mentally recall previous events remains one of the greatest mysteries of our time. Through our memory, we are able to mentally reconstruct earlier experiences, retrieve information that we thought we have already forgotten and remember things that help us arrive at important decisions in our lives. It is easy to see why our memory plays a significant role in our lives individually and as members of the society. However, there has been a great deal of controversy as to how human memory really works or why we are able to recall some things and forget all the rest.
There are also questions which ask why we are able to repress certain memories or if we truly are able to repress them in the first place. In most of these attempts, there are at least two general ways used to approach the subject of human memory—the psychological and physiological aspects. The psychological aspect of human memory primary deals with the association of previous memory with current environmental stimuli. It also deals with the general types of memory known in cognitive science: sensory memory, long-term memory and short-term memory.
This approach is also behavioral in many ways as human behaviors involving the use of memory are oftentimes the sources of the psychological interpretation of our ability mentally recall past events and experiences. In essence, the approach of psychology in dealing with the concept of memory is generally theoretical with focus on the explanations as to why the different phenomena corresponding to our memories occur or otherwise. On the other hand, the physiological aspect of approaching the subject of human memory typically deals with the physical composition of the brain including the roles performed by its vital parts.
The physiological analysis of human memory rests primarily on evidence found on laboratory tests that involve a careful examination of the anatomy of the human brain. Human Memory and Psychology In Psychology, memory is generally classified in three ways: sensory memory, short-term memory and long-term memory. Sensory memory refers to first level of memory where it retains an impression of the stimulus for a very brief period after the stimulus itself has disappeared or has ended.
As a result, this first level of memory quickly dissipates and is, therefore, un-interpreted. Sensory memory is further categorized into three types, which include: iconic (for visual stimuli), echoic (for aural stimuli) and haptic (for touch) memories. Short-term memory is a person’s capability to hold a limited amount of information, usually 3 to 7 pieces of the information such as letters or icons, for a few seconds. Short-term memory enables us to temporarily hold information for a brief duration so that we can recall such information upon immediate necessity.
For example, short-term memory allows the reader to temporarily hold in mind the beginning of this sentence so that the thought will be complete after this sentence has been read in full. This category of memory decays quickly in about 200 milliseconds; the “chunking” of information—the hyphenation of a phone number for instance—can help increase the capacity of our short-term memory. On the other hand, long-term memory has little decay of information. On the contrary, the decay of information in this type of memory can occur for a long duration.
Information stored in the short-term memory can be passed on to the long-term memory for future retrieval, usually through the mental recollection of the information or through the recognition of the stored information through external stimuli. Information stored in the long-term memory can also be deleted either through decay or through the interference of some other external stimuli. However, it is debated as to whether we are really able to delete our long-term memories or if we are simply unable to access them due to certain mental difficulties (Conlan & Hobson, 1999).
In 1956, George Miller theorized that we can store information in our short-term memory more efficiently if we are able to “chunk” the information. In the previous example of the digits in a telephone number being hyphenated, the pieces of information—namely, the individual numbers—are chunked in parts, thereby allowing us to store them faster in our short-term memory. Miller, however, recognizes the argument that there is hardly any singe or universal determinant which qualifies what exactly is a “chunk” of information.
Donald Broadbent (1966) hypothesized in his Filter Model that irrelevant messages in the information were removed or filtered out before they are processed for their meaning. Moreover, the physical characteristics of a message in the form of a perceivable auditory sound can also cause the receiver of the stimulus to focus its attention to the incoming message. In 1968, Richard Atkinson and Richard Shiffrin presented their “Multi-store Model” where they argue that the memory of human beings typically involves three stages in chronological sequence.
First, information passes through the sensory memory. Since the sensory memory decays fast and can only hold a very limited amount of information, it simply holds the most relevant information presented from the external stimuli. Second, our attention aids us in selecting information from our sensory memory so that the information can be stored in the short-term memory. Finally, the careful repetition of the information stored in the short-term memory will cause the information to be stored eventually in our long-term memory.
Information stored in our long-term memory can then be retrieved for future purposes as they can last for several minutes to an entire lifetime. Alan Baddeley and Graham Hitch (2001) first introduced their Model of Working Memory in 1974. In their model, they assert that our working memory is composed of the “central executive” which feeds information to its “slave systems”. These slave systems are composed of the phonological loop, the visuo-spatial sketchpad and the episodic buffer, each of which has its own domain-specific task.
For instance, the phonological loop accepts information in the form of auditory verbal information from the central executive. The visuo-spatial sketchpad, on the other hand, accepts visual information. Interestingly, the episodic buffer allows for the linking of information coming from the two other slave domains in order to form a cohesive piece of information. One important feature of psychology when dealing with human memory is that it focuses on the relations of the representations of memory derived from observations of human behavior.
For example, the conceptual representations of long-term and short-term memories have risen from the observations of psychologists and other scholars in the case of patients suffering from memory loss or amnesia. There are countless other examples which show this important feature of psychology. In essence, it is worth noting that psychology offers one significant way for us to understand better how our memory works despite still being shrouded in mystery. Human Memory and the Brain’s Physiology The physiological setup of our memory and the different processes associated with it in our brain are complex.
Today, further researches are being made in order to probe deeper and understand better that complexity. Prior to the formation of memory, our brain’s cerebral cortex perceives and processes the information received from our senses. The specialized parts of our cortex receive sensory inputs that comprise our immediate memories or our memories which last for several milliseconds. The information received and encoded in the cortex, when needed, is activated which we can then use as working memory. The prefrontal lobe region of our brains is primarily responsible for enabling us to have short-term memories.
Moreover, we are able to form long-term memories through our hippocampus, the small region in our brain’s cortex that transfers information from our short-term memory to our long-term memory. The hippocampus also forms associations about the properties of certain objects and compares new sensations to those that have already been recorded earlier. Through a repeated process of sending information back and forth the hippocampus, we are able to strengthen that information in our brain which eventually leads to a long-term memory that no longer needs the help of the hippocampus.
The result is what is called “semantic memory,” the type of memory associated with the memory of concept-based knowledge such as meanings and understandings. “Spatial memory”, however, is somehow confined within the hippocampus. It is the type of memory that enables us to remember the spatial features of our surroundings and to drive around the city and navigate its streets, for instance. “Procedural memory” is memory that typically involves our know-how about certain actions such as riding a bicycle. It is also the type of memory that does not involve the hippocampus but rather the motor cortex, basal ganglia and cerebellum.
In essence, what we typically call as “memory” is actually a stored pattern of connections created by the nerve cells or neurons in our brain. These connections have certain points called the “synapse” and most adult brains contain trillions of synapses. Remembering Things There is no general consensus as to when exactly or at what age human beings are able to remember things. In fact, adults generally suffer from what is called as “childhood amnesia” or the inability to recall the earliest experiences during their childhood years.
There are studies, however, that show humans typically unable to remember their life before they were about three to four years old. That being the case, there is a certain point during the transition between our childhood and adolescent years when we are able to form memories. Sigmund Freud gives his explanation as to why adults are unable to recall their past experiences when they were still children. According to Freud, childhood amnesia is part of the mind’s efforts to inhibit memories of traumatic events from being retrieved.
Moreover, he argues that such repression is a normal process in the psychosexual development of children (Grunbaum, 1983). Another theory which explains why we suffer from childhood amnesia is the argument that the minds of infants are not neurologically mature enough to form long-term memories concerning one’s life. More specifically, the hippocampus and cerebral cortex of children are not mature enough until they reach the age of 3 or 4. The inability of infants to exhibit comprehensible language is another explanation offered as to why adults suffer from childhood amnesia.
In the theory, it is argued that the lack of language capacity prevents infants from properly encoding autobiographical memories into a form that is at least comprehensible in the languages of adults. The fact the infants are limited to simple one-word utterances suggests that they are unable to form complete autobiographical utterances and, therefore, long-term memories. In rare cases when children are able to recall from memory certain moments in their infant years, they are merely able to recall the simple utterances which they thought represent the objects that they can remember.
Another explanation for childhood amnesia is the idea that the world for infants is entirely different from the world for adults at least in terms of perspective. While adults may exhibit a strong sense of self-awareness, infants do not. Children at the age of two, however, have been suggested to have already developed a sense of self-awareness, evidence of which is the manner in which they react to their self-image in front of a mirror. If adults suffer from childhood amnesia, the argument that human beings are capable of forgetting memory is often the subject of much debate.
On one hand, there is the contention that we are capable of forgetting because even our long-term memories suffer from decay through time and through certain biological ailments. On the other hand, there is the contention that we may not necessarily have forgotten memories which we thought we already have forgotten; we may simply be having difficulties retrieving them from our long-term memory storage. To this day, the mysteries of human memory are yet to be fully understood. What we do know, however, is that we are capable of creating memories and retrieving them for certain reasons.
The process of creating memories, storing them and retrieving them is more complex than we can begin to think. At the least, there are psychological and physiological concepts and theories that can help us better grasp that complexity and, hopefully, use them to explain our own personal experiences. References Atkinson, R. C. , & Shiffrin, R. M. (1968). Human Memory: A Proposed System and Its Control Processes. In The Psychology of Learning and Motivation (Vol. 8). London: Academic Press. Baddeley, A. , & Hitch, G. (2001). Working Memory in Perspective. East Sussex, UK: Psychology Press.
Broadbent, D. E. (1966). The Well Ordered Mind. American Educational Research Journal, 3(4), 281-295. Conlan, R. , & Hobson, J. A. (1999). States of Mind: New Discoveries About How Our Brains Make Us Who We Are. New York: John Wiley & Sons, Inc. Grunbaum, A. (1983). Freud’s Theory: The Perspective of a Philosopher of Science. Proceedings and Addresses of the American Philosophical Association, 57(1), 5-31. Miller, G. (1956). The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information. The Psychological Review, 63, 81-97.