por What is sensory memory?
The sensory memory It is the ability to retain information from the senses after the perceived stimulus has disappeared. It refers to the objects detected through the senses, which are temporarily retained in the sensory registers.
Sensory records contain a high information storage capacity, but they are only capable of maintaining precise images of sensory information for a very limited time.
Two main types of sensory memory have been established: iconic memory and echoic memory.
The first type is a component of the visual memory system. The second is a component of short-term memory that is responsible for retaining auditory information.
Sensory memory characteristics
– Sensory memory is the persistence of a stimulus over time, beyond its physical presence. That is, it is the memory that allows the effect of a stimulus to continue even though it has disappeared.
For example, if a person visualizes a scene that produces sensations of terror or fear, sensory memory allows them to continue experiencing those sensations when they have stopped seeing it.
– Sensory memory is a memory capacity that reveals the close relationship between perceptual systems and cognitive processes.
– The functioning of one cannot be explained without the other. Perception without cognition would lead to a passive way of connecting with the world, since the mind would not perform any task with the information captured through the senses.
– Learning and cognitive functioning would be impossible without the capture of information and new knowledge from the outside world through perceptual systems.
– Sensations are the starting point of perception, and perception is the first step towards the cognitive process. Without sensation there is no perception and without perception there is no memory.
– Perception and memory have more common elements: perception goes beyond sensations, it is usually defined as the mechanism by which the brain gives meaning to sensations.
– Sensory memory processes and stores significant information. It is also involved in the functioning of basic perception processes, such as detection, discrimination, recognition or identification.
functions
The main function of sensory memory is to retain stimulation even after it has disappeared. In this way, it increases the chances of being able to process information, especially in the case of short-duration stimuli.
In this sense, sensory memory acts as an information bridge that allows increasing the duration of the presentation of stimuli.
If the brain could only process information while the stimulus is present and can be registered by the senses, a lot of knowledge would be lost along the way.
The functioning of sensory memory can be exemplified while driving a car. While a person drives a car, he can perceive multiple signs on the road that indicate the rules of the road, directions on how to reach the destination, etc.
Normally, the visualization of these elements is very brief due to the speed of the car, which allows capturing the stimuli for short periods of time.
However, the stimulation produced by these elements is prolonged at the brain level for a longer period of time than the presentation of the stimulus itself.
This ability is carried out by the brain through the action of sensory memory, which allows the stimulation to be preserved despite the fact that the stimulus is no longer being visualized.
Sensory memory types
At present there is a high scientific consensus in establishing two main types of sensory memory: iconic memory and echoic memory.
Iconic memory refers to visual sensory memory, that is, to the sensory memory processes that are set in motion when stimuli are perceived through sight.
For its part, echoic memory defines auditory sensory memory and is set in motion when stimuli are captured through the ear.
iconic memory
Iconic memory is the sensory memory register related to the visual domain. It is a component of the visual memory system that includes both short-term and long-term visual memory.
Iconic memory is characterized by forming a memory store of very short duration (less than 1,000 milliseconds), however, it has a high capacity (it can retain many elements).
The two main components of this type of sensory memory are visual persistence and informational persistence.
The first is a brief pre-categorical visual representation of the physical image created by the sensory system. The second forms a longer-lasting memory store that represents a coded version of the visual image.
The functioning of this type of sensory memory appears to be related to the visual sensory pathway. A prolonged visual representation begins with the activation of the photoreceptors of the retina. Rods and cones undergo stimulation after removal of the stimulus.
Iconic memory is responsible for providing a flow of visual information to the brain, which can be collected and sustained over time. One of the most important roles of iconic memory is its involvement in the detection of changes in the visual environment:
– Temporary integration: iconic memory activates the integration of visual information and provides a constant stream of images in the brain’s primary visual cortex.
– Change blindness: Several investigations show that the brief representation of the iconic memory is especially relevant when it comes to detecting changes in the visual environment.
– saccadic eye movements: the most recent investigations suggest that iconic memory is responsible for providing continuity to the experience during saccadic eye movements (rapid eye movements).
echoic memory
Echoic memory is one of the sensory memory registers that is responsible for retaining auditory information. It would be a component of short-term memory equivalent to iconic memory for the storage of visual information.
Echoic memory is capable of storing large amounts of auditory information in a period of time between three and four seconds. The sound stimulation remains active in the mind and can be played again during that short period of time.
The first works on this type of memory were carried out by the psychologist Alan Baddeley in the working memory model, which is made up of an executive system and two subsystems: the visuospatial agenda, related to iconic memory, and the phonological loop. , which processes auditory (echoic) information.
According to Baddeley’s model (one of the most widely used memory theories today), the phonological loop processes information in two different ways.
The first one consists of a store with the capacity to retain information for three or four seconds. The second is a process of sub-vocal repetition that maintains the memory trace through the use of an inner voice.
Currently, the technique that makes it possible to measure echoic memory in a more objective way is the disparity potential task. In this technique, changes in auditory brain activation are recorded using electroencephalography.
References
Ruiz-Vargas, JM (2010). Manual of Psychology of memory. Madrid: Synthesis.
L. and Tulving, E. (1994). Memory systems 1994. Cambridge (MA): MIT Press.
Schacter, DL, Wagner, AD, & Buckner, RL (2000). Memory systems of 1999.