Chapter 2, page 30
Sensory Register
The first step in processing the sentence about lobsters is that the information is very briefly stored
in the first memory store, the sensory register, which stores visual information for a short time. Visual
information, such as a word read in a book, remains in the sensory register for only about 500
milliseconds (Sperling, 1960). If the information does not move into the next memory store, short-term
memory, it is completely lost from the system within about half a second.
The auditory sensory register is the sensory register that briefly stores sounds. Information in the
auditory sensory register lasts up to perhaps two seconds before the sounds are lost from memory
(Darwin, Turvey, & Crowder, 1972; Moray, Bates, & Barnett, 1965). The auditory sensory register
sometimes helps you figure out what someone said to you, even if you weren’t paying attention. For
example, have you ever had an experience like this: Some speaks to you to you while you were occupied
with something else, and you did not attend to what they said right away. You had no idea at this moment
what was said. Yet when you turned your attention to what was said a second or two later, you were able
to piece together at least some of the words. This occurs because of the auditory sensory register, which
gives you access to what you hear for up to several seconds, even if you were not attending to it.
Information in the sensory register is stored in a form that has not yet been classified or interpreted.
For example, let’s return to Rachel as she is processing the word lobster. How is the first letter, L, stored
in her visual sensory register? The visual sensory register stores the “L” not as the letter L but as shape
(just two lines that are connected). The lines have not yet been classified as an “L,” or as the first letter in
lobster. Similarly, the auditory register records sounds that have not yet been interpreted. If Rachel hears
the word lobster, the auditory sensory register contains an impression of the sounds heard, but these
sounds would not yet be recognized as the word lobster.
Working Memory, or Short-term Memory
Working memory, also called short-term memory, is the memory store that holds information and
processes that are currently active. This memory store holds the information of which we are currently
aware.
The size of working memory is extremely limited. Although it is difficult to pin down the exact size,
a widely-cited conclusion by the psychologist George Miller (1956) is that people can hold only 7 ± 2
pieces of information in working memory at one time. For instance, one can remember seven numbers or
seven items in a list. The limited size of working or short-term memory plays an important role in many
current models of how humans learn. As we will see in later chapters, the limited size of working memory
will help us understand why some instructional methods work better than others.
To test the limited size of your own working memory, listen or read a series of single-digit numbers,
and then try to recall the numbers you have heard. Try it with the list of numbers below. View these
numbers long enough to say each to yourself. Next, cover the numbers and try to write down as many as
you can on a piece of paper.
5 8 1 9 6 7 2
Most adults can recall these 7 numbers, or at least 6 of them. Now try it with these numbers.
9 7 2 0 8 4 7 3 2 5
Few people can remember 10 digits, and those who do use special memory strategies of the sort that we
will discuss shortly.
As new information in stored into working memory, old information fades. If you have ever had the
experience of trying to remember a phone number long enough to dial it, only to have someone in the room
say something to you, you have experienced this phenomenon. The information you had retained in your
working memory was simply replaced as you tried to take in the new information that was being