What Is The Modal Model Of Memory?

Scientists once suggested that humans have an unlimited capacity to store memories. However, although people's senses are often repeatedly bombarded with an assortment of information—including what is seen, heard, tasted, scented, and felt—people often only remember a fraction of what they encounter. Sometimes referred to as the Atkinson-Shiffrin model, the modal model of memory was formulated in 1968 by psychology professors Richard Atkinson and Richard Shiffrin to explain why people forget specific details. 

According to the modal model of memory theory, as information enters the brain, it is encoded and stored in three distinct stores of memory, including the sensory register, short-term memory, and long-term memory. Exploring this three-stage model of memory and how modal forms of memory affect how you might process information may be beneficial to understanding your own memory. 

Models of memory

For millennia, philosophers, psychologists, and scientists have studied the process of human memory. Around 350 BCE, Greek philosopher and scientist Aristotle wrote On the Soul, one of his significant works about the connection between the body and mind. Mid-century physicist and inventor Robert Hooke also put forward a work on memory, which, though lesser known, is often hailed for the completeness of the memory model it presents.

Out of the current models of memory, the modal model of memory, also known as the multi-store model or the Atkinson-Shiffrin model, is often referred to as one of the classics. It has had a far-reaching influence on several memory models that have been developed more recently, including the following: 

• Levels of Processing Model - Craik and Lockhart (1972)
• Tulving's Model of Memory - Endel Tulving (1972)
• Working Memory - Baddeley and Hitch (1974)

The Atkinson-Shiffrin model has been reviewed, revised, and clarified since it was first proposed.

Stages of the modal model of memory

Richard Atkinson (1929-) and Richard Shiffrin (1942-) are renowned psychologists and cognitive scientists who developed the theory of model memory under the name of the Atkinson-Shiffrin model of memory. They published their theory in a chapter titled Human Memory: A Proposed System and Its Control Processes. In their theory, Atkinson and Shiffrin suggest that humans have three stores of memory known as:

• Sensory registers
• Short-Term stores
• Long-Term stores

Sensory register or sensory memory

The Atkinson-Shiffrin memory model proposes that each sense has a sensory register or sensory memory system. These systems retain information for a fraction of a second to a few seconds. In the sensory register, no processing of the information takes place. Therefore, no meaning is attached to it. If not attended to, the information is filtered out, lost, and forgotten. If the information is attended to, it is transferred to the short-term memory. During the few moments that the sensory registers hold on to information, a phenomenon known as the "cocktail party effect" can take place.

Imagine being in a crowded room with several groups carrying on their own conversations. You attend only to the conversation you are a part of, and it seems like you hear nothing else. Your ears are still picking up all the sounds in the room, but because your attention is focused elsewhere, any memory of these sounds quickly fades away. If a particular word or phrase catches your attention, like your name, you are no longer filtering out sounds and are "hearing" the other conversation. 

Similar effects can happen for each of the other senses. The sensory registers act as "buffers" (a term used by Atkinson and Shiffrin) since they prevent higher cognitive functions from being flooded with all the information one's senses perceive. It is estimated that of the thousands of bits of information one's senses perceive, about1% make it to short-term memory.

Due to limitations in researching some of the registers, the Atkinson-Shiffrin model focuses on two, called echoic memory and iconic memory:

• Iconic memory: The register for the visual system (sight)
• Echoic memory: The register for the auditory system (hearing)

One example of echoic memory is the "What did you say?" theory. After hearing someone, you might ask, "What did you say?" before you have processed what they said. However, before they can repeat themselves, you may suddenly realize what it was and respond. It might seem like you hear their words after they occur. 

Short-term store or short-term memory

According to Atkinson and Shiffrin, the next stage of the modal memory model is short-term storage, often referred to as short-term memory. Short-term memory comprises information you are consciously aware of at any given time. Hence, short-term memory is sometimes called working memory.

Information can be stored in short-term memory for up to 30 seconds without effort to remember or rehearse. After this time, it decays and is lost or forgotten. With rehearsal or encoding, the information can be held in the short-term memory for extended periods and even transferred to long-term memory.

Rehearsal can take different forms depending on the type of information. According to the modal model of memory, however, much of the encoding that takes place in short-term memory is auditory encoding. Auditory processes occur to help someone rehearse a piece of information in a different manner from how it was perceived.

For example, imagine yourself trying to remember a phone number. After glancing at a phone number posted on the fridge in the kitchen, you repeat the number to yourself while heading to the living room in search of your phone (visual perception but auditory encoding). Without any rehearsal, you may only be able to recall a few digits when you find the phone.

The capacity of short-term memory (how many pieces of information it can hold) is still a matter of active research among scientists. In the 1950s, before the Atkinson-Shiffrin model was presented, American psychologist George Miller, who is hailed as one of the founders of cognitive psychology, proposed his theory that, on average, short-term memory can hold around seven bits of information. His theory came to be known as Miller’s Magic Number.

More modern research has pointed to the fact that the actual capacity of short-term memory depends on several factors. These include familiarity with or relevance of the information stored, as well as the size of the information (such as short words versus long words or three-digit numbers versus 10-digit numbers).

Connected to Miller's theory is the idea that "chunking" can be used to improve short-term memory. Chunking psychology, as it's sometimes called, can make absorbing and remembering information easier. For instance, 8-2-6-4-9-7 represents six different bits of information, whereas 82-64-97 are only three and may be more convenient for individuals to commit to their short-term memory.

Long-term store or long-term memory

When speaking of memories, many people refer to the long-term memory store as described by the modal model of memory. A long-term store is a permanent (lifelong) store of memories received from the short-term store. Long-term memory holds all the information people know but are not consciously thinking of at any moment. According to the Atkinson-Shiffrin model, information is continually perceived by the sensory registers, attended to and encoded by the short-term memory, and then passed on to the long-term memory with a limitless capacity.

Storage in long-term memory can take different forms, with visual, auditory, and semantic being the most common. Furthermore, of these three, semantics is the most used storage level in long-term memory. Extensions of the Atkinson-Shiffrin model, such as the levels of the processing model, often point to semantic encoding as the best way to ensure the retention of information in long-term memory.

There are several ways to improve your long-term memory, including the spacing effect. This effect involves taking breaks between learning new information by spacing out your learning. During the break, refrain from engaging in other activities that could interfere with your brain's processing, encoding, and storing the information you have learned. Students studying for an exam may see better results regarding how much they recall if, instead of studying for a two-hour block, they break it up into smaller segments with quiet time in between.

Strengths of the modal model of memory

One of the strengths of the modal model is its simplicity: three separate stores with information moving along from one store to the next. The model can be easily explained and understood. However, it still retains some measure of thoroughness as it looks at how information is handled in each store. Other strengths may include the following. 

It has influenced future research

The modal model of memory provides expansive coverage of short-term memory. These studies have allowed other researchers to create a vast body of experimental information about different aspects of short-term memory, as described by Atkinson and Shiffrin.

Other researchers support aspects

The theory's distinction of short-term memory from long-term memory, as well as the relationship between them, is supported by solid evidence from the research of other scientists. This research includes the modal memory model that explains the serial position effect (primacy and recency effect) on verbal behavior.

For example, if presented with a list of words and asked to recall them shortly afterward, individuals are more likely to remember the first few words (primacy effect) and the last few words (recency effect) but not those in the middle. That is because the first words are committed to the long-term memory while the last words are held in the short-term memory.

Amnesia studies support the concept of the separate memory stores

Among psychologists, the most well-known case of amnesia may be that of Henry Molaison, sometimes referred to as Patient HM. For over 50 years, Molaison was the subject of numerous studies about how memories are formed and where they are stored. At age 27, he had undergone brain surgery for epilepsy, where a portion of his brain was removed. As a result of the procedure, Molaison was left with acute amnesia, where his short-term memory was intact, but he could not form new long-term memories.

Criticisms of the modal model of memory

Some attempts to disprove parts of the model have served as clarification or extensions of its theories instead of refuting the model altogether. Later, Atkinson and Shiffrin revised the model by including the sensory registers as part of the short-term store. Below are a few of the criticisms. 

Structure of the short-term memory

Later research has shown that short-term memory operates more complexly than Atkinson and Shiffrin had described. For instance, Baddeley and Hitch (1974 and revised in 2000) suggest that short-term memory has a controlling system they call the central executive system (CES). The CES manages the functions of three subordinate systems called:

• Phonological loop
• Visuospatial sketchpad
• Episodic buffer

Different long-term memory stores

Subsequent work conducted by Endel Tulving describes separate locations for the storage of different forms of long-term memory. These include the episodic store for memories of events and the semantic store for memories of all information that may be considered general knowledge. He also proposed a procedural store for memories about learning and performing skills. Evidence of the procedural store is found in the ability of amnesiac Henry Molaison to learn and improve his skill in drawing a star. Molaison, however, could not recall the instances in which he learned the skill in the past. He was also unable to learn word meanings (i.e., semantics).

Transfer to long-term memory happens at various levels

The modal model of memory emphasizes the function of rehearsal in transferring information from short-term memory to long-term memory. Later studies, like the levels of processing theory of Craik and Lockhart, present the idea that rehearsal is not always necessary. They suggest that learner motivation, past experiences, and similarities between the learning and recall environments can affect how deeply the information is processed and how it is transferred to long-term memory.

Memories can form an integral part of the personality, as they hold your name, how to brush your teeth, your experiences, and the information you have learned and are currently learning. Without giving it a second thought, you trust your memory to hold all the essential information you need later. There are instances, however, when your memory can fail you, and memory loss can begin affecting your quality of life.

Support options for memory loss

Memory loss can be distressing for those experiencing it. If you aren't sure where to turn, consider contacting a licensed therapist for professional support. There are multiple ways to attend therapy, and those with barriers like financial insecurity or inaccessibility can also receive these mental health services through options such as online therapy platforms like BetterHelp.

Research shows that online therapy is effective in helping individuals with memory loss. In a study published in Perspectives on Psychological Science—a peer-reviewed academic journal—researchers looked at the benefits of improving memory in therapy. In particular, the study mentions using memory-enhancing methods through online therapy platforms. The study concludes that these modalities can improve memory.

Online therapy can be a valuable tool if you are hoping to bolster your cognitive functioning. Unlike traditional counseling, you can connect with a licensed therapist from the convenience of your own home. In addition, your therapist can send you worksheets and tools you can view immediately on your device, which might be helpful if you frequently forget what isn't in front of you.