Sensory Register
The information we attend to and perceive with our eyes and ears is registered or received in our thinking process. It is then stored, temporarily, in our sensory register before transferred to short-term memory for temporary retention.
Sensory register consists of several sensory stores (one in each sense modality such as vision and hearing) each holding information very briefly when relevant stimuli are presented. Each sensory register has very limited capacity.
It is in the sensory register that perception, or detection, takes place along with pattern recognition and the assignment of meaning.
The first step is detecting the stimulus, that is, seeing and/or hearing it, followed by briefly storing it. Then, based on what information we already possess, we recognize the stimulus and determine what it means.
We have a visual sensory register and an auditory one, enabling us to register both incoming sights and sounds. Both enable us to retian environmental information, after it has disappeared, for about half a second in the visual register and three seconds in the auditory register.
Sensory register: visual vs. auditory stores
Our sense organs are constantly bombarded with information.
At this very moment, you are receiving visual information from this literature, there is probably auditory information in the form of human voices or traffic noise, and you can feel something from that part of you in contact with your chair.
There is a separate sensory store for each type of information:
- iconic memory, a visual sensory store, is used for visual information,
- echoic memory, auditory sensory store, is used for auditory information,
- the haptic store, concerned with touching and feeling, and so on.
There has been most research on iconic memory, hence it’s pertinent to focus on it.
Sperling (1960) carried out the classic research on iconic memory. He presented a visual array containing three rows of four letters each for 50 milliseconds (1/20 of a second).
Participants could only report four or five letters when asked to provide full recall but claimed to have seen many more. Sperling assumed this happened because visual information had faded before most of it could be reported.
Sperling (1960) tested the above hypothesis by telling participants to recall only part of the information presented.
Sperling’s results supported his assumption—part recall was very good and suggested iconic memory held nine or ten items.
Full recall was much lower because information in iconic memory decays within about 0.5 seconds and so all the items couldn’t be recalled in time.
Why is iconic memory useful? The processes involved in visual perception always operate on information in iconic memory rather than directly on the visual environment.
Iconic memory Opens in new window is also useful when watching movies. Movies are often presented at 24 frames per second with each frame differing slightly from the previous one. We perceive smooth rather than jerky motion because the iconic store allows us to integrate information from successive frames in a way that wouldn’t be possible in its absence.
