What Is Sensory Memory And Why Is It Important?

When most people think of sensory memory, they may think about memories that they have of certain smells, tastes, or sights. However, scientifically, this is not generally what quantifies sensory memory, also known as working memory. 

Sensory memory in psychology can be defined as the memory process that stores information taken in by the senses. These sensory impressions might be stored very briefly—particularly in relation to other types of memory—as human memory generally relies on sensory information to create memories and increase understanding. However, it generally does not have to retain impressions of sensory input long-term in order to maintain memory stores or sort through information.

Many may find that they have a sensory memory. However, there are cases where things can go wrong with it, such as in disorders like schizophrenia and Alzheimer's. While these can be extremely unfortunate circumstances, if they are tested early enough, there may be ways to help prevent or slow down the deterioration of sensory memory. 

The ability to slow down the loss of sensory memory—or the loss of its functions—generally depends on the condition in question, and the severity of one’s symptoms. 

Read on to learn more about sensory memory and the essential role it can play in the development and retention of our memories.

Sensory memory in psychology

The American Psychological Association (APA) generally defines sensory memory as the brief storage of information derived from the senses that exists in an unprocessed form to be recoded into another memory for comprehension. It can also be called ultra-short-term memory, lasting only a few seconds (or even less than a few seconds) for many. 

Psychology and the five senses (sight, sound, feel, taste, touch)

When you encounter something with one of the five senses (i.e., taste, touch, smell, sight, or hearing), your brain is thought to create a flash of sensory memory. For a very brief time, you can remember what it is that you experienced with your senses. Your brain then decides whether to store this information for future use in short-term memory or to discard it, such as in eidetic memory.

Common characteristics of sensory memory

As there are five senses, there are five types of sensory memory that are generally regarded by the scientific community. However, all forms of sensory memory are thought to have some common characteristics. These characteristics can remain true regardless of which sense is being used or whichever part of the brain is processing the memory. For example, Sensory memory does not require your attention. It is completely automatic for most. 

The next thing to consider is that sensory memory is only stored in the part of the brain associated with the sense that provides the information. For example, Sensory memory created from auditory stimuli will only be processed or stored by the part of the brain that relates to hearing.

Furthermore, sensory memory can be exceptionally detailed. Even though it only lasts a short time for most, it can be extremely keen in your mind during that brief period. For example—if you look at an object and quickly close your eyes, the sensory memory of the object will likely be so clear, that you might feel as though you still have your eyes open.

The final consideration regarding the characteristics of sensory memory is that it can be extremely brief. It is often continuously being replaced by new sensory memories as stimuli taken in by the senses continue or increase. Once sensory memory is gone, there is no way to recover it based on current scientific understanding at the time of this publication. Many believe that unless the brain relegates the information to short-term memory, all sensory memories can be lost very quickly.

Types of sensory memory

Just as there are five senses, there are five types of sensory memory that are currently regarded by the scientific community. Each can be distinct and work independently of the other types. Although there are five types of sensory memory, we will consider the three that have been meticulously studied by researchers:

Iconic memory

Iconic memory generally refers to memories that are created through vision or sight. When you see an object, close your eyes, and still see it in your mind's eye for a very brief period, your brain might be using iconic memory. 

In this form of memory, sights are thought to be taken in through the photoreceptor cells in the eyes, then transmitted to the occipital lobe of the brain—where the sensory memory can be briefly stored and evaluated.

Echoic memory

Echoic memory is also known to many as auditory memory. It is generally considered to be the sensory memory for auditory input and stimuli. 

When you are listening to someone speak in the background and they stop talking, but you still note the tone or pitch of their voice, this can be your auditory memory at work. Auditory stimuli can be picked up by the tiny hair-like sensory cells in the ears known as cilia, or cochlear hair cells. This information might then be transmitted to the temporal lobe of the brain, where the auditory memory can be stored—often for less than a second.

Haptic memory

Haptic memory is thought by many to be related to touch. This type of sensory memory encompasses just about everything that we can feel throughout our bodies. 

Anytime you make contact with something, the memory of that touch might remain for a split second. When this happens, you can note this as your haptic memory at work. 

Current scientific information suggests that the body is covered in sensory receptors that relay information to the spinal cord, which can then transmit incoming information to the post central gyrus of the parietal lobe of the brain.

The role of sensory memory

Sensory memory, although generally extremely brief, can play a vital role in your overall memory processes. Without sensory memory, new short-term and long-term memories might not form properly. As you take in sights, sounds, smells, tastes and feelings of stimuli, your brain makes a snap decision as to whether to relegate that information to short-term memory or discard it. Once it is let go, it is lost forever. 

Once an individual’s sensory memory sends messages to their short-term memory system, repetition, or relative importance of the information may or may not relegate it to long-term memory. Once in long-term memory, the information can be recalled at any time, or until such time as the long-term memory fails.

Sensory memories and survival instincts

Sensory memory also might play an important role in one’s survival instincts. Even though it only lasts for a short time, this flash of memory can alert you to threats if the proper processes are utilized. Because the senses are constantly at work in many, new sensory memories might form before the old ones have dissipated. This is why, if something moves almost imperceptibly, you might notice it right away. In the example above, your iconic memory will likely be telling you that the object or threat that you are looking at has moved.

Sensory memory examples

There are many examples of sensory memory, as the senses are constantly at work, feeding our brains information. When you are typing on your keyboard and feel that tingle in your finger pad as your finger leaves the key, this is sensory memory. You remember the feel of the key even though you are no longer touching it. It only lasts for a moment, but it is there, nonetheless.

Iconic memory

The most common example of iconic memory is when you look at an object and close your eyes and still see the object (albeit very briefly). For example, if you look at a bright light bulb and close your eyes, you will still see it for a split second before it goes away. If you were asking someone about a book and they flashed you the cover for a moment, your mind would remember that cover for a very short period of time before relaying it for future retrieval to the short-term memory.

Echoic memory

The example of echoic memory that is easiest to consider is the pitch of a voice. If someone suddenly screeches in a high pitch, then goes silent, your mind remembers that pitch for momentarily before discarding it. This is why you may cringe for a split second after the screech has already ended. When you hear someone say something important, the auditory memory holds on to it for a split second before relaying it to your short-term memory for storage.

Haptic memory

A good example of haptic memory is pushing a button or running your finger over a zipper. For a split second, after your finger leaves the object, your mind will remember the feeling the stimuli elicited. If you are really paying attention, you may notice it as a slight tingle in the pad of your finger. When you touch something hot—such as a stove—as a young child, haptic memory recalls the pain almost instantaneously before moving that information to short-term memory, which then relays it to long-term memory, so that you remember not to touch the stove again.

Mismatch negativity (MMN)

Mismatch negativity, or MMN, is the earliest brain response that can be measured physiologically related to auditory or visual stimuli. It is a very important survival response that enables to nervous system to detect unusual and possibly dangerous events by noticing minute differences in stimuli already perceived in the past. You do not have to be paying attention to what you are hearing or seeing in order for MMN to function. Essentially, your senses are creating new sensory memories constantly, so even though the sensory memory only lasts for a moment, it allows for comparison. Mismatch negativity is the measure of the brain that recognizes that something has changed. George Sperling pioneered the study of sensory memory and played a key role in developing a greater understanding of sensory memory, and how it relates to MMN.

Sensory memory disorders

Mismatch negativity can play a large role in diagnosing certain disorders. When MMN is low or not present, it can mean that there are problems with an individual’s sensory memory. There are several mental health or memory disorders that can affect sensory memory; however, the following two medical conditions are the most common: schizophrenia and Alzheimer’s disease.

Schizophrenia and auditory sensory memory

In an extensive study done by a group of psychiatrists, information was found that suggests that a decrease in the function of sensory memory can be associated with schizophrenia. In the study, several groups of people were studied in their responses to auditory stimuli, particularly measuring mismatch negativity. There was a group of patients with schizophrenia, a group of patients with bipolar affective disorder, and a group of healthy adults.

The study found that, while both bipolar affective disorder and schizophrenic patients might have had significant reductions in MMN, the MMN in patients living with schizophrenia was significantly lowered. This could provide insight as to why these patients have increased negative symptoms; in fact, the study noted that negative symptoms of the disorder were thought to be exacerbated by the low MMN, whereas positive ones did not seem to be affected.

Alzheimer’s and auditory sensory memory

Another study done by neuroscience researchers studied the effects of auditory stimuli in Alzheimer's patients. They found information that suggests that mismatch negativity was severely decreased as the patient's condition deteriorated. This could be one reason why Alzheimer's patients might have trouble forming new memories, as new memories cannot be created if sensory memory is not functioning properly.

Mental health support for managing sensory memory issues

If you or a loved one are having difficulty making new memories, you may have a medical disorder that is affecting your sensory memory. There are several tests available that assess sensory memory and mismatch negativity. If you suspect that you are having memory problems, you may consider seeking out professional help to get tested. If the test results return showing you are having low MMN and sensory memory issues, further tests can determine the cause and follow up with appropriate treatment. 

While sensory memory issues can be a sign of a serious problem that requires medical attention, people can still benefit from the assistance of a counselor or therapist who can help keep people and their senses engaged. Your online therapist can also help you through the emotional experiences of memory attachment, understanding and management. 

The online format of this therapeutic intervention may help more people to feel comfortable opening up about these personal experiences, possibly removing a barrier to treatment for some. 

Online therapy for cognitive impairment and short-term memory

Studies have found information that suggests that online cognitive therapy can help those who have experienced memory impairment. In one report, researchers found that online cognitive treatments were generally effective in bolstering memory through the utilization of a messaging service. Another study found information that suggests that online cognitive training (CT) can be beneficial when improving the short-term memory of those experiencing cognitive impairment—a treatment option that can be facilitated by a trained and licensed online therapist. 

These findings are in line with an increasingly large amount of research that points to online therapy as a valuable component of treatment for a wide range of cognitive impairments, such as memory loss arising out of schizophrenia, Alzheimer’s Disease, or other mental health disorders.