Classic Research on Memory — The Brown-Peterson Technique

A typical psychological experiment on memory can be set up like this:

You are instructed to look at several words briefly, and then count backwards for about half a minute before recalling those words.

The experiment described represents an example of classic research on short-term memory using the Brown-Peterson technique. The results of this research have been lauded as evidence for the existence of a short-term memory store as distinct from long-term memory and for the interference theory of forgetting. Specifically, the experiments indicated that new information held in memory for only a very short time (i.e., less than a minute) and/or not rehearsed, is typically forgotten due to decay (Eysenck & Keane, 2005; Matlin, 2002; Sternberg, 2003).

According to the standard model of memory, information either decays and is thus lost from short-term memory or is held in short-term memory through the process of rehearsal. Rehearsal allows one to refresh information, thus preventing the decay from eliminating it. Therefore, forgetting would occur in the absence of such rehearsal (Eysenck & Keane, 2005; Matlin, 2002).

Additionally, information is lost from short-term memory due to displacement. Once short-term memory has reached its capacity, either additional information is ignored or information already in short-term memory is displaced in order to accommodate the new information. In the case of these experiments, forgetting occurs because new information (i.e., the counting backwards) interferes with rehearsal and ultimately displaces the older information in short-term memory (i.e., the words). More specifically, the interference that occurs in this task represents retroactive interference because the activity of counting backwards occurs after the presentation of the word items and before their recall (Eysenck & Keane, 2005; Matlin, 2002; Sternberg, 2003).

The experiment described measures iconic memory — the form of sensory memory that briefly holds a visual representation of what has been perceived. In contrast, echoic memory refers to the transitory store that holds relatively unprocessed and unattended auditory input that persists briefly after the sound has disappeared. Research has indicated that the maximum numbers of items maintained in the auditory sensory memory is about 5 words lasting 2–10 seconds (Matlin, 2002; Schweickert, 1993).

Echoic memory can also be measured using the Brown-Peterson technique by adding the auditory element to the experiment. Rather than looking at the words, they can be spoken out loud in order to assess the capacity of the echoic memory and the decay effect of interference. Additionally, experiments which involve the presentation of messages in both ears and instructions to shadow one while ignoring the other are used to assess the duration of unattended auditory information (Eysenck & Keane, 2005; Sternberg, 2003).

References

Eysenck, M. W. & Keane, M. T. (2005). Cognitive psychology: A student’s handbook, (5th ed.). New York, NY: Psychology Press.

Matlin, M. W. (2002). Cognition (5th ed.). New York, NY: Harcourt College Publishers.

Schweickert R. (1993). A multinomial processing model for degradation and reintegration in immediate recall. Memory & Cognition, 21(2), 168–175.

Sternberg, R. J. (2003). Cognitive psychology (3rd ed.). Belmont, CA: Thompson/Wadsworth.