Sensory memory
Encyclopedia
During every moment of an organism's life, sensory information is being taken in by sensory receptors and processed by the nervous system
. Humans have five main senses
: sight, hearing, taste, smell, and touch. Sensory memory (SM) allows individuals to retain impressions of sensory information after the original stimulus has ceased. A common demonstration of SM is a child's ability to write letters and make circles by twirling a sparkler at night. When the sparkler is spun fast enough, it appears to leave a trail which forms a continuous image. This "light trail" is the image that is represented in the visual sensory store known as iconic memory
. The other two types of SM that have been most extensively studied are echoic memory
, and haptic memory
; however, it is reasonable to assume that each physiological sense has a corresponding memory store. Children for example have been shown to remember specific "sweet" tastes during incidental learning
trials but the nature of this gustatory store is still unclear.
of a presented stimulus affects transfer into more stable forms of memory.
Four common features have been identified for all forms of SM:
It is widely accepted that all forms of SM are very brief in duration; however, the approximated duration of each memory store is not static. Iconic memory for example has an average duration of 500 ms which tends to decrease with age. The SM is made up of spatial or categorical stores of different kinds of information, each subject to different rates of information processing and decay. Genetics also play a role in SM capacity; mutations to the brain-derived neurotrophic factor (BDNF), a nerve growth factor, and N-methyl-D-aspartate (NMDA) receptors
, responsible for synaptic plasticity
, decrease iconic and echoic memory capacities respectively.
represents SM for the visual sense of visual perception
/sight
. Visual information is detected by photoreceptor cells in the eyes which is then sent to the occipital lobe
in the brain. Iconic memory was the first sensory store to be investigated with experiments dating back as far as 1740. One of the earliest investigations into this phenomenon was by Johann Andreas Segner
(1704 - 1777) a German physicist
and mathematician
. In his experiment, Segner attached a glowing coal to a cartwheel and rotated the wheel at increasing speed until an unbroken circle of light was perceived by the observer. He calculated that the glowing coal needed to make a complete circle in under 100ms to achieve this effect which he determined was the duration of this visual memory store. Segner's estimate of the duration of iconic memory is not far off of what George Sperling
found over 100 years later using his famous partial report paradigm.
represents SM for the auditory sense of hearing
. Auditory information travels as sound waves which are sensed by hair cells in the ears. Information is sent to and processed in the temporal lobe
. The first studies of echoic memory came shortly after Sperling investigated iconic memory using an adapted partial report paradigm. Today, characteristics of echoic memory have been found mainly using a Mismatch Negativity
(MMN) paradigm which utilizes EEG
and MEG
recordings. MMN has been used to identify some of the key roles of echoic memory such as change detection and language acquisition. Change detection, or the ability to detect an unusual or possibly dangerous change in the environment independent of attention, is key to the survival of an organism. With regards to language, a characteristic of children who begin speaking late in development is reduced duration of echoic memory.
represents SM for the tactile sense of touch
. Sensory receptors all over the body detect sensations such as pressure, itching, and pain. Information from receptors travel through afferent neurons in the spinal cord to the postcentral gyrus
of the parietal lobe
in the brain. This pathway comprises the somatosensory system. Evidence for haptic memory has only recently been identified resulting in a small body of research regarding its role, capacity, and duration.. Already however, fMRI studies have revealed that specific neurons in the prefrontal cortex
are involved in both SM, and motor preparation which provides a crucial link to haptic memory and its role in motor responses.
of memory traces or comparison of information. Likewise, the capacity and duration of SM cannot be influenced by top-down control; a person cannot consciously think or choose what information is stored in SM, or how long it will be stored for. The role of SM is to provide a detailed representation of our entire sensory experience for which relevant pieces of information can be extracted by short-term memory (STM) and processed by working memory
(WM). STM is capable of storing information for 10-15 seconds without rehearsal while working memory actively processes, manipulates, and controls the information. Information from STM can then be consolidated into long-term memory
where memories can last a lifetime. The transfer of SM to STM is the first step in the Atkinson–Shiffrin memory model which proposes a structure of memory.
See also =
Nervous system
The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous...
. Humans have five main senses
Sense
Senses are physiological capacities of organisms that provide inputs for perception. The senses and their operation, classification, and theory are overlapping topics studied by a variety of fields, most notably neuroscience, cognitive psychology , and philosophy of perception...
: sight, hearing, taste, smell, and touch. Sensory memory (SM) allows individuals to retain impressions of sensory information after the original stimulus has ceased. A common demonstration of SM is a child's ability to write letters and make circles by twirling a sparkler at night. When the sparkler is spun fast enough, it appears to leave a trail which forms a continuous image. This "light trail" is the image that is represented in the visual sensory store known as iconic memory
Iconic memory
Iconic memory is the visual sensory memory register pertaining to the visual domain. It is a component of the visual memory system which also includes visual short term memory and long term memory . Iconic memory is described as a very brief . A small decrease in visual persistence occurs with age...
. The other two types of SM that have been most extensively studied are echoic memory
Echoic memory
Echoic memoryis a type of sensory memory and auditory in nature; a component of sensory memory that is specific to retaining auditory information. Unlike visual memory, in which our eyes can scan the stimuli over and over, the auditory stimuli cannot be scanned over and over. Auditory stimuli is...
, and haptic memory
Haptic memory
Haptic memory is a form of sensory memory that refers to the recollection of data acquired by touch after a stimulus has been presented. Haptic memory is used regularly when assessing the necessary forces for gripping and interacting with familiar objects. It may also influence one’s interactions...
; however, it is reasonable to assume that each physiological sense has a corresponding memory store. Children for example have been shown to remember specific "sweet" tastes during incidental learning
Latent learning
Latent learning is a form of learning that is not immediately expressed in an overt response; it occurs without obvious reinforcement to be applied later....
trials but the nature of this gustatory store is still unclear.
Characteristics
SM is considered to be outside of cognitive control and is instead an automatic response. The information represented in SM is the "raw data" which provides a snapshot of a person's overall sensory experience. Common features between each sensory modality have been identified; however, as experimental techniques advance, exceptions and additions to these general characteristics will surely evolve. The auditory store, echoic memory, for example, has been shown to have a temporal characteristic in which the timing and tempoTempo
In musical terminology, tempo is the speed or pace of a given piece. Tempo is a crucial element of any musical composition, as it can affect the mood and difficulty of a piece.-Measuring tempo:...
of a presented stimulus affects transfer into more stable forms of memory.
Four common features have been identified for all forms of SM:
- The formation of a SM trace is independent of attention to the stimulus.
- The information stored in SM is modality specific. This means for example, that echoic memory is for the exclusive storage of auditory information, and haptic memory is for the exclusive storage of tactile information.
- Each SM store represents an immense amount of detail resulting in very high resolution of information.
- Each SM store is very brief and lasts a very short period of time. Once the SM trace has decayed or is replaced by a new memory, the information stored is no longer accessible and is ultimately lost. All SM stores have slightly different durations which is discussed in more detail on their respective pages.
It is widely accepted that all forms of SM are very brief in duration; however, the approximated duration of each memory store is not static. Iconic memory for example has an average duration of 500 ms which tends to decrease with age. The SM is made up of spatial or categorical stores of different kinds of information, each subject to different rates of information processing and decay. Genetics also play a role in SM capacity; mutations to the brain-derived neurotrophic factor (BDNF), a nerve growth factor, and N-methyl-D-aspartate (NMDA) receptors
NMDA receptor
The NMDA receptor , a glutamate receptor, is the predominant molecular device for controlling synaptic plasticity and memory function....
, responsible for synaptic plasticity
Synaptic plasticity
In neuroscience, synaptic plasticity is the ability of the connection, or synapse, between two neurons to change in strength in response to either use or disuse of transmission over synaptic pathways. Plastic change also results from the alteration of the number of receptors located on a synapse...
, decrease iconic and echoic memory capacities respectively.
Iconic memory
Iconic memoryIconic memory
Iconic memory is the visual sensory memory register pertaining to the visual domain. It is a component of the visual memory system which also includes visual short term memory and long term memory . Iconic memory is described as a very brief . A small decrease in visual persistence occurs with age...
represents SM for the visual sense of visual perception
Visual perception
Visual perception is the ability to interpret information and surroundings from the effects of visible light reaching the eye. The resulting perception is also known as eyesight, sight, or vision...
/sight
Sight
Sight may refer to:*Visual perception*Sight , used to assist aim by guiding the eye*Sight , a 2005 concert DVD by Keller Williams*Sight , a first-person shooter video game created by FPS Creator...
. Visual information is detected by photoreceptor cells in the eyes which is then sent to the occipital lobe
Occipital lobe
The occipital lobe is the visual processing center of the mammalian brain containing most of the anatomical region of the visual cortex. The primary visual cortex is Brodmann area 17, commonly called V1...
in the brain. Iconic memory was the first sensory store to be investigated with experiments dating back as far as 1740. One of the earliest investigations into this phenomenon was by Johann Andreas Segner
Ján Andrej Segner
Johann Segner was a Hungarian born German scientist. He was born in the Kingdom of Hungary, in the former Hungarian capital city of Pressburg ....
(1704 - 1777) a German physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
and mathematician
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....
. In his experiment, Segner attached a glowing coal to a cartwheel and rotated the wheel at increasing speed until an unbroken circle of light was perceived by the observer. He calculated that the glowing coal needed to make a complete circle in under 100ms to achieve this effect which he determined was the duration of this visual memory store. Segner's estimate of the duration of iconic memory is not far off of what George Sperling
George Sperling
George Sperling is an American cognitive psychologist. He is a Distinguished Professor of both Cognitive Science and Neurobiology & Behavior at the University of California, Irvine. Sperling documented the existence of iconic memory...
found over 100 years later using his famous partial report paradigm.
Echoic memory
Echoic memoryEchoic memory
Echoic memoryis a type of sensory memory and auditory in nature; a component of sensory memory that is specific to retaining auditory information. Unlike visual memory, in which our eyes can scan the stimuli over and over, the auditory stimuli cannot be scanned over and over. Auditory stimuli is...
represents SM for the auditory sense of hearing
Hearing (sense)
Hearing is the ability to perceive sound by detecting vibrations through an organ such as the ear. It is one of the traditional five senses...
. Auditory information travels as sound waves which are sensed by hair cells in the ears. Information is sent to and processed in the temporal lobe
Temporal lobe
The temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain....
. The first studies of echoic memory came shortly after Sperling investigated iconic memory using an adapted partial report paradigm. Today, characteristics of echoic memory have been found mainly using a Mismatch Negativity
Mismatch negativity
The mismatch negativity or mismatch field is a component of the event-related potential to an odd stimulus in a sequence of stimuli. It arises from electrical activity in the brain and is studied within the field of cognitive neuroscience and psychology. It can occur in any sensory system, but...
(MMN) paradigm which utilizes EEG
EEG
EEG commonly refers to electroencephalography, a measurement of the electrical activity of the brain.EEG may also refer to:* Emperor Entertainment Group, a Hong Kong-based entertainment company...
and MEG
Magnetoencephalography
Magnetoencephalography is a technique for mapping brain activity by recording magnetic fields produced by electrical currents occurring naturally in the brain, using arrays of SQUIDs...
recordings. MMN has been used to identify some of the key roles of echoic memory such as change detection and language acquisition. Change detection, or the ability to detect an unusual or possibly dangerous change in the environment independent of attention, is key to the survival of an organism. With regards to language, a characteristic of children who begin speaking late in development is reduced duration of echoic memory.
Haptic memory
Haptic memoryHaptic memory
Haptic memory is a form of sensory memory that refers to the recollection of data acquired by touch after a stimulus has been presented. Haptic memory is used regularly when assessing the necessary forces for gripping and interacting with familiar objects. It may also influence one’s interactions...
represents SM for the tactile sense of touch
Somatosensory system
The somatosensory system is a diverse sensory system composed of the receptors and processing centres to produce the sensory modalities such as touch, temperature, proprioception , and nociception . The sensory receptors cover the skin and epithelia, skeletal muscles, bones and joints, internal...
. Sensory receptors all over the body detect sensations such as pressure, itching, and pain. Information from receptors travel through afferent neurons in the spinal cord to the postcentral gyrus
Postcentral gyrus
The lateral postcentral gyrus is a prominent structure in the parietal lobe of the human brain and an important landmark. It is the location of primary somatosensory cortex, the main sensory receptive area for the sense of touch...
of the parietal lobe
Parietal lobe
The parietal lobe is a part of the Brain positioned above the occipital lobe and behind the frontal lobe.The parietal lobe integrates sensory information from different modalities, particularly determining spatial sense and navigation. For example, it comprises somatosensory cortex and the...
in the brain. This pathway comprises the somatosensory system. Evidence for haptic memory has only recently been identified resulting in a small body of research regarding its role, capacity, and duration.. Already however, fMRI studies have revealed that specific neurons in the prefrontal cortex
Prefrontal cortex
The prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas.This brain region has been implicated in planning complex cognitive behaviors, personality expression, decision making and moderating correct social behavior...
are involved in both SM, and motor preparation which provides a crucial link to haptic memory and its role in motor responses.
Relationship with other memory systems
SM is not involved in higher cognitive functions such as consolidationMemory consolidation
Memory consolidation is a category of processes that stabilize a memory trace after the initial acquisition. Consolidation is distinguished into two specific processes, synaptic consolidation, which occurs within the first few hours after learning, and system consolidation, where...
of memory traces or comparison of information. Likewise, the capacity and duration of SM cannot be influenced by top-down control; a person cannot consciously think or choose what information is stored in SM, or how long it will be stored for. The role of SM is to provide a detailed representation of our entire sensory experience for which relevant pieces of information can be extracted by short-term memory (STM) and processed by working memory
Working memory
Working memory has been defined as the system which actively holds information in the mind to do verbal and nonverbal tasks such as reasoning and comprehension, and to make it available for further information processing...
(WM). STM is capable of storing information for 10-15 seconds without rehearsal while working memory actively processes, manipulates, and controls the information. Information from STM can then be consolidated into long-term memory
Long-term memory
Long-term memory is memory in which associations among items are stored, as part of the theory of a dual-store memory model. According to the theory, long term memory differs structurally and functionally from working memory or short-term memory, which ostensibly stores items for only around 20–30...
where memories can last a lifetime. The transfer of SM to STM is the first step in the Atkinson–Shiffrin memory model which proposes a structure of memory.
See also =
- MemoryMemoryIn psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....
- Visual memoryVisual memoryVisual memory describes the relationship between perceptual processing and the encoding, storage and retrieval of the resulting neural representations. Visual memory occurs over a broad time range spanning from eye movements to years in order to visually navigate to a previously visited location...
- Iconic memoryIconic memoryIconic memory is the visual sensory memory register pertaining to the visual domain. It is a component of the visual memory system which also includes visual short term memory and long term memory . Iconic memory is described as a very brief . A small decrease in visual persistence occurs with age...
- Echoic memoryEchoic memoryEchoic memoryis a type of sensory memory and auditory in nature; a component of sensory memory that is specific to retaining auditory information. Unlike visual memory, in which our eyes can scan the stimuli over and over, the auditory stimuli cannot be scanned over and over. Auditory stimuli is...
- Haptic memoryHaptic memoryHaptic memory is a form of sensory memory that refers to the recollection of data acquired by touch after a stimulus has been presented. Haptic memory is used regularly when assessing the necessary forces for gripping and interacting with familiar objects. It may also influence one’s interactions...