What is Sensory Memory?
Sensory memory is a repository for incoming sensory information. Raw, unanalyzed data that are derived from the senses are held here very briefly. It refers to an initial process that holds environmental information in its raw form for a brief period of time, from an instant to several seconds.
The purpose of sensory memory is to maintain the representation of a stimulus long enough so that it can be recognized. Although you may have glanced at a visual scene for only a very brief time, say, 100 milliseconds, a representation of the scene is preserved in sensory memory for longer than that. This gives the information a chance to be operated psychologically upon the selection and pattern recognition mechanisms.
|Assume for a minute that as you are talking to the person seated next to you at a dinner party, you happen to overhear other guests talking about a new movie you want to see. However, you do not want to appear rude, so you try to pay full attention to your dinner partner, but you really want to hear what the others are saying about the movie. Even though you cannot listen to both conversations simultaneously, you can store, for a relatively short period, bits and pieces of the other conversation. So you might be listening to your dinner partner but switch your attention to the other conversation once you hear the word amazing.|
As another example, assume that you are doing your homework in front of the TV. Your roommate comes in and says, “That’s a great commercial!” although you have not been listening, right after your roommate makes this statement, you realize that you heard the words Coca-Cola. You realize it is a Coke commercial, and you say, “Yeah, I really like that one, too.
|Adapted from: Wayne D. Hoyer, Deborah J. MacInnis "Consumer Behavior"|
Sensory memory uses a short-term storage area known as sensory store Opens in new window (sometimes called sensory register). Our sensory store can house information from any of the five senses, but iconic memory—sensory memory of things we see—and echoic memory—sensory memory of things we hear—are the most commonly studied.
Iconic memory is a visual sensory memory. It holds a brief “snapshot” of what you have just looked at. Iconic memory has a very short duration; it lasts only about 250 to 300 milliseconds (Averbach & Sperling, 1961; Sperling, 1960). Iconic memory is at work when you drive by a sign and see it quickly, only to realize after you have driven past that it was a sign for Applebee’s.
Echoic memory is an auditory sensory store. You can think of it as an “echo” of what you have just heard. It lasts considerably longer than iconic memory, on the order of several seconds longer (Darwin, Turvey & Crowder, 1972). The Coke example illustrates echoic memory. Here is another example: You may have found that when someone asks you a question, and you are really listening, you can say, “What did you say?” and actually “play back” what the person said.
Information in sensory memory is stored in its actual sensory form. In other words, we store the word amazing as it sounds, and we store it exactly, not as a synonym. Information in sensory memory is also short-lived, generally lasting from a quarter of a second to several seconds. If the information is relevant, we will be motivated to process it further, and it may enter what is called short-term memory. However, if we do not analyze that information, it is lost.