Sensory memory is an ultra short term memory that stores traces of the information gained from the sensory stimuli.
It’s an ability of the human brain to retain accurate and photographic information from the shortest possible period of exposure of the five senses: sight, smell, touch, hearing, and taste.
During the process of the formation of sensory memory, specific brain areas receive information from all sensory organs, dedicating specific types of sensory memory to each of them.
What Are the Types of Sensory Memory?
There are three subtypes of sensory memory:
- Iconic memory
- Echoic memory
- Haptic memory
Iconic Memory
Sensory iconic memory (or visual sensory memory) refers to the ability for visual storage of images. The mental representations of the sensory stimuli are stored in a dedicated part of the brain for an ultra-short period of time.
When we take a quick look around in the room we are in, and then close our eyes, the visual mental representations we see in front of our eyes are produced by the iconic memory.
Echoic Memory
Echoic memory (or auditory sensory memory) is ultra-short-term retention of the information received from the auditory stimuli. This type of memory is a short term sensory memory related to hearing. Namely, it stores audio (sound) information in the dedicated part of the brain.
When we hear a sound, this information is transferred to the brain via the auditory nerves with the help of electric signals. The echoic memory is established after the brain processes the sounds and retains the auditory information.
Haptic Memory
The memory of the information collected through touch is referred to as a haptic memory.
Namely, the sensory receptors detect various sensations, including pressure, itching, and pain. They are kept in the haptic memory for an ultra-short period of time before they disappear or are transferred to short-term memory.
Based on the areas of the human body which receive the stimuli, haptic memory can be divided into cutaneous (memory of a touch received by the neuron cells located in the skin), and kinesthetic (memory encoded upon information received by the neuron cells located in the muscles).
Which Medical Disorders Can Affect Sensory Memory?
There is a wide range of neurological conditions, disorders, and diseases that contribute to dysfunctionality, decay, or loss of sensory memory:
- Agnosia
- Alzheimer’s Disease
- Amnesia
- Brain injury
- Dementia
- Huntington’s disease
- Parkinson’s disease
- Wernicke-Korsakoff Syndrome
- Vascular Dementia
- Lewy body Dementia
Disorders of sensory memory (as well as memory in general) can be caused by one or more triggering factors, which include:
- Head trauma (concussions)
- Brain trauma
- Aging
- Substance abuse
- Narrowing of the arteries that provide blood to the brain
- Vitamin deficiencies
- Brain tumor
- Inheriting genetic diseases (such as Alzheimer’s disease)
- Mental health conditions (such as depression or anxiety)
To Sum Up
The ultra short term memory of a sensory experience is called sensory memory. It allows individuals to retain the information gained via the sensory organs for a brief period of time.
This type of memory represents a remembered image, a scent, or a sound. Regardless if we’re dealing with hearing, touch, or taste – sensory memories are fleeting.
Every sensory experience changes the connection between the neurons in the cerebral cortex. Considering the brain’s ability to process, retain, and create a mosaic of the information gained from the sensory stimuli, it turns out that our brain is literally made of memories.
In this way, individuals with strong auditory memory are better at remembering details and order; visual learners tend to be better at seeing things as a whole, while the individuals who have a stronger kinesthetic memory are more suited to the physical aspect of learning.
Fun Facts
Did you know?
- Spoken language is the most common example of echoic memory.
- Iconic memory remembers images, echoic memory remembers sounds, while haptic memory remembers information from our sense of touch.
- The process of retaining the sounds in echoic memory is automatic, i.e. even if we don’t listen to a sound intentionally, our mind will nonetheless form an echoic memory.
- By storing the words of a speech, echoic memory helps us understand the uttered sentence.
- We don’t always pay full attention to what somebody’s saying to us. However, if we ask that person to repeat what they have just said, it will sound familiar to us, due to the fact that echoic memory has unintentionally stored the information of the sound we heard.
- The duration of echoic memory ranges from 2 to 4 seconds.
- Haptic memory decays after less than 2 seconds.
- Iconic memory lasts less than a half of a second. It’s the shortest type of sensory memory.
- Lack of focus and concentration during the formation of sensory memory can lead to less accurate retrieval of it.
- Due to the closeness of the olfactory bulb to the area of the cerebral cortex where the signals from the sensory organs are encoded, the smell could be ever more related to memory than the other senses.