- Sensory memory is a very short-term memory store for information being processed by the sense organs. Sensory memory has a limited duration to store information, typically less than a second.
- It is the first store of the multi-store model of memory.
- Sensory memory can be divided into subsystems called the sensory registers: such asiconic, echoic, haptic, olfactory, and gustatory.
- Generally, iconic memory deals with visual sensing, echoic memory deals with auditory sensing, and haptic memory deals with tactile sensing.
- George Sperling’s experiments provided crucial initial insight into the workings of sensory memory.
In This Article
What is Sensory Memory?
Sensory memory is a brief storage of information in humans wherein information is momentarily registered until it is recognized, and perhaps transferred to short-term memory (Tripathy & Öǧmen, 2018).
Sensory memory allows for the retention of sensory impressions following the cessation of the original stimulus (Coltheart, 1980).
Throughout our lives, we absorb a tremendous amount of information via our visual, auditory, tactile, gustatory, and olfactory senses (Coltheart, 1980).
Since it is impossible to permanently register each and every impression we have captured via these senses, as we momentarily focus on a pertinent detail in our environment, our sensory memory registers a brief snapshot of our environment, lasting for several hundred milliseconds.
Attention is the first step in remembering something, if a person’s attention is focused on one of the sensory stores then the data is transferred to short-term memory.
Types of Sensory Memory
Sensory memory can be divided into subsystems called the sensory registers: such as iconic, echoic, haptic, olfactory, and gustatory.
Iconic memory is the visual sensory memory register which stores visual images after its stimulus has ceased (Pratte, 2018). While iconic memory contains a huge capacity, it declines rapidly (Sperling, 1960). Information stored in iconic memory generally disappears within half a second (depending on the brightness).
Close your eyes for one minute, and hold your hand about 25cm from your face ad then open and close your eyes. You should see an image of your hand that fades away in less than a second (Ellis, 1987).
Examples of Iconic Memory
- Seeing an ant on the wall
- Seeing an aircraft in the sky as you walk down the road
- Seeing the change in traffic lights
A recent study sought to examine the hypothesis that iconic memory comprises fine-grained and coarse-grained memory traces (Cappiello & Zhang, 2016). The study employed a mathematical model to quantify each trace. The outcome suggested that the dual-trace iconic memory model might be superior to the single-trace model.
Echoic memory is the sensory memory for incoming auditory information (sounds).
The information which we hear enters our organism as sound waves. These are sensed by the ears’ hair cells and processed afterwards in the temporal lobe. The processing of echoic memories generally takes 2 to 3 seconds (Darwin, Turvey & Crowder, 1972).
Clap your hands together once and see how the sound remains for a brief time and then fades away.
Examples of Echoic Memory
- Hearing the bark of a dog
- Hearing the whistle of a police officer
- Hearing the horn of a car
The recent use of the Mismatch Negativity (MMN) paradigm which employs MEG and EEG recordings, has unveiled many characteristics of echoic memory (Sabri, Kareken, Dzemidzic, Lowe & Melara, 2003).
Consequently, language acquisition and change detection have been identified as some crucial functions of echoic memory. Additionally, a study on echoic sensory alterations suggests that a presentation of a sound to a participant is sufficient to shape a trace of echoic memory which can be compared with a different sound (Inui, Urakawa, Yamashiro, Otsuru, Takeshima, Nishihara & Kakigi, 2010).
Moreover, a study of language acquisition indicates that children who start speaking late are likely to have an abridged echoic memory (Grossheinrich, Kademann, Bruder, Bartling & Suchodoletz, 2010).
Furthermore, lesions on or damage to the parietal lobe, the hippocampus or the frontal lobe too, would likely shorten echoic memory or/and slow down its reaction time (Alain, Woods & Knight, 1998).
Haptic memory involves tactile sensory memories procured via the sense of touch through the sensory receptors which can detect manifold sensations such as pain, pressure, pleasure or itching (Dubrowski, 2009). These memories tend to last for about two seconds.
It enables us to combine a series of touch sensations and to play a role in identifying objects we can’t see. E.g. Playing a song on guitar, sharp pencil on the back of hand.
Examples of Haptic Memory
- Feeling a raindrop on your skin
- Feeling a key while typing on the keyboard
- Feeling a string as you play the guitar
The information which enters through sensory receptors travel via the spinal cord’s afferent neurons to the parietal lobe’s postcentral gyrus through the somatosensory system (Shih, Dubrowski & Carnahan, 2009) (D”Esposito, Ballard, Zarahn & Aguirre, 2002).
fMRI studies suggest that certain neurons within the prefrontal cortex engage in motor preparation and sensory memory. Motor preparation provides a significant link to the haptic memory’s role in motor responses.
In 1960, the cognitive psychologist George Sperling conducted an experiment using a tachistoscope to briefly present participants with sets of 12 letters arranged in
a matrix which had three rows of letters (Schacter, Gilbert & Wegner, 2011). The participants of the study were asked to look at the letters for approximately 1/20th of a second, and recall them soon afterward.
During this procedure, described as free recall, the participants were able, on average, to recall 4 to 5 of the 9 letters which they had seen (Sperling, 1960).
While the conventional psychological view at the time would have pointed out that this outcome was merely the result of the participants’ not being able to retain all the letters in their minds, Sperling seemed to believe that the participants had actually mentally registered all the letters which they had seen (Sperling, 1960).
Sperling hypothesized that the participants had forgotten this information while attempting to recall it. In other words, Sperling held that all of the nine letters were in fact stored in the participants’ memory for a very short time, but that this memory had faded away. Hence, the participants could recall only 4 or 5 of the 9 letters.
Afterward, Sperling ran a second slightly different experiment using the partial report technique. As earlier, the participants were shown three rows of letters for 1/20th of a second (Sperling, 1960).
However, this time, as the letters disappeared, the participants heard either a low-pitched, a medium-pitched, or a high-pitched tone.
The participants who heard the low-pitched tone had to report the bottom row, those who heard the medium-pitched tone had to report the middle row, and those who heard the high-pitched tone had to report the top row.
The individuals managed to recall the letters if the tone was sounded within 1/3rd of a second following the display of the letters (Sperling, 1960). However, the ability to report the letters declined drastically as the interval increased beyond 1/3rd of a second. An interval of more than one-second rendered recalling almost impossible.
The experiment seemed to indicate that the participants were able to recall the information as long as they were focused on the pertinent row before the memory of the letters vanished. Hence, if the tone was heard after the memory had faded, they could not recall the letters.
Alain, C., Woods, D. L., & Knight, R. T. (1998). A distributed cortical network for auditory sensory memory in humans. Brain research, 812 (1-2), 23-37.
Cappiello, M., & Zhang, W. (2016). A dual-trace model for visual sensory memory. Journal of Experimental Psychology: Human Perception and Performance, 42 (11), 1903.
Coltheart, M. (1980). Iconic memory and visible persistence. Perception & psychophysics, 27 (3), 183-228.
Darwin, C. J., Turvey, M. T., & Crowder, R. G. (1972). An auditory analogue of the Sperling partial report procedure: Evidence for brief auditory storage. Cognitive Psychology, 3 (2), 255-267.
D”Esposito, M., Ballard, D., Zarahn, E., & Aguirre, G. K. (2000). The role of prefrontal cortex in sensory memory and motor preparation: an event-related fMRI study. Neuroimage, 11 (5), 400-408.
Grossheinrich, N., Kademann, S., Bruder, J., Bartling, J., & Von Suchodoletz, W. (2010). Auditory sensory memory and language abilities in former late talkers: a mismatch negativity study. Psychophysiology, 47 (5), 822-830.
Inui, K., Urakawa, T., Yamashiro, K., Otsuru, N., Takeshima, Y., Nishihara, M., … & Kakigi, R. (2010). Echoic memory of a single pure tone indexed by change-related brain activity. BMC neuroscience, 11 (1), 1-10.
Pratte, M. S. (2018). Iconic memories die a sudden death. Psychological science, 29 (6), 877-887.
Sabri, M., Kareken, D. A., Dzemidzic, M., Lowe, M. J., & Melara, R. D. (2004). Neural correlates of auditory sensory memory and automatic change detection. Neuroimage, 21 (1), 69-74.
Shih, R., Dubrowski, A., & Carnahan, H. (2009, March). Evidence for haptic memory. In World Haptics 2009-Third Joint EuroHaptics conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (pp. 145-149). IEEE.
Sperling, G. (1960). The information available in brief visual presentations. Psychological monographs: General and applied, 74 (11), 1.
Tripathy, S. P., & Öǧmen, H. (2018). Sensory memory is allocated exclusively to the current event-segment. Frontiers in psychology, 9, 1435.
- Sperling, G. (1960). The information available in brief visual presentations. Psychological monographs: General and applied, 74(11), 1.
- Öğmen, H., & Herzog, M. H. (2016). A new conceptualization of human visual sensory-memory. Frontiers in psychology, 7, 830.
- Sligte, I. G., Vandenbroucke, A. R., Scholte, H. S., & Lamme, V. (2010). Detailed sensory memory, sloppy working memory. Frontiers in psychology, 1, 175.