A signal is sent to your brain every time you experience something through one of your senses – taste, touch, smell, sight, and hearing. Think of the soft touch of a baby’s skin, or the sight of spring buds on a tree after a long, hard winter. These are things you can recall, even if you aren’t experiencing the sense of feeling or seeing these things. That is sensory memory.
The processing of sensory memory is much like activity in a train station. You feel, see, hear, taste or smell something that enters your brain. Everything you experience through your senses goes through the main station. From there it is encoded (turned into code) and sent on the your short-term memory — where it is held for a brief time until the brain decides whether to keep it and store it in long term memory or throw it out with the trash. Due to the amount of experiences the brain has to process in short periods of time, nothing is held for long here before it is sent off.
Your sensory memory pays close attention to the signals the information sends out so it is able to make the right connections for the next stop. If somehow the information gets shorted out things could end up going where there are not supposed to, and that could cause problems in retrieval.
Your sensory memory’s basic function is to transmit. It does not have to remember different cognitive functions, nor does it hold any information on its own. Sensory memory is not consciously stored, and it has no control as to what is stored, or how long. Sensory memory provides the details and it is up to other parts of the brain to figure out what to do with them — that is the job of working memory, which processes the information and controls where it goes — either to short term or long-term memory.
There are three main types of sensory memory: visual (iconic), auditory (echoic), and touch (haptic). The visual and auditory are the most extensively studied, although due to the advancement of treatment for spinal cord injuries research on the haptic portion of sensory memory is increasing.
- Iconic memory. Visual stimulation forms a picture in your mind. A common, and good example of iconic memory would be to watch a child making images with a sparkler. They spin the sparkler fast and it makes designs with the ‘light trail.’ The continuous images of the letters or designs forms stimulate your visual senses. Visual information is found by the photoreceptor cells in the eyes and is sent to the occipital lobe in the brain.
- Echoic memory. Audio memory gives us echoic memories, or mental echoes of stimulation. Auditory information is sound waves that are sensed by the hair cells in your ears and travels to the temporal lobe of the brain. Here it is able to detect changes in the environment. This has been the key to survival of any organism. These changes could be as simple as a language difference, or as the detection of some unusual activity in your surroundings that could prove to be dangerous — such as a lion in the jungle. A reduced duration of echoic memory would be delayed development in learning language skills.
- Haptic memory. Haptic memory has to do with the sensations our body feels (pain, stimulation, itching, etc.) We have sensory receptors all over our bodies, and any touch sends off signals that travel through different neurons in the spinal cord to the ‘post central gyrus’ of the parietal lobe in the brain. Studies have found that specific neurons in the prefrontal cortex are involved in haptic memory with regards to reaction to motor response.
About the author:
Ron White is a two-time U.S.A. Memory Champion and memory training expert. As a memory keynote speaker he travels the world to speak before large groups or small company seminars, demonstrating his memory skills and teaching others how to improve their memory, and how important a good memory is in all phases of your life. His CDs and memory products are also available online at BrainAthlete.com.
Sources:
Oracle Think Press — Cognitive Processes: http://library.thinkquest.org/26618/en-5.2.2=sensory%20memory.htm
Wikipedia: – Sensory Memory: http://en.wikipedia.org/wiki/Sensory_memory
