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. MMN has been used to identify some of the key roles of echoic memory such as change detection and language acquisition. Today, characteristics of echoic memory have been found mainly using a mismatch negativity (MMN) paradigm which utilizes EEG and MEG recordings.
The first studies of echoic memory came shortly after Sperling investigated iconic memory using an adapted partial report paradigm. The echoic sensory store holds information for 2–3 seconds to allow for proper processing. Information is sent to and processed in the temporal lobe. Auditory information travels as sound waves which are sensed by hair cells in the ears. Echoic MemoryĮchoic memory represents SM for the auditory sense of hearing. 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. The visual sensory store has a relatively high capacity, with the ability to hold up to 12 items. 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. Iconic memory, for example, holds visual information for approximately 250 milliseconds. 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. All SM stores have slightly different durations which is discussed in more detail on their respective pages. Once the SM trace has decayed or is replaced by a new memory, the information stored is no longer accessible and is ultimately lost.
Each SM store represents an immense amount of detail resulting in very high resolution of information.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. The information stored in SM is modality specific.The formation of a SM trace is only weakly dependent on attention to the stimulus.Four common features have been identified for all forms of SM: The auditory store, echoic memory, for example, has been shown to have a temporal characteristic in which the timing and tempo of a presented stimulus affects transfer into more stable forms of memory. 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 information represented in SM is the "raw data" which provides a snapshot of a person's overall sensory experience. SM is considered to be outside of cognitive control and is instead an automatic response. However, sensory memories might be related to a region of the thalamus, which serves as a source of signals encoding past experiences in the neocortex. 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. 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.
This "light trail" is the image that is represented in the visual sensory store known as iconic memory. When the sparkler is spun fast enough, it appears to leave a trail which forms a continuous image. A common demonstration of SM is a child's ability to write letters and make circles by twirling a sparkler at night. Sensory memory (SM) allows individuals to retain impressions of sensory information after the original stimulus has ceased. Humans have five traditional senses: sight, hearing, taste, smell, touch. Sensory information is stored in sensory memory just long enough to be transferred to short-term memory. During every moment of an organism's life, sensory information is being taken in by sensory receptors and processed by the nervous system.
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