Memory and VARK Part 1: Sensory Memory

Along with Sperry’s work on split-brains, the VARK theorists also list Alan Baddeley’s work on memory in their bibliography. No direct citation is provided for his work, so I cannot be sure what exactly is cited from it. After reviewing the source, I had found a handful of places where Baddeley discusses the processing of different senses/sensory modalities. In this series of posts, I will review those discussions and try to infer what is relevant to VARK (or other theory of learning modality preference) studies.

There are four different places in Baddeley’s 1984 book where he discusses modality differences in memory. They are:

1.      sensory memory
2.      encoding of memories
3.      semantic memories
4.      working memory

In this post, I will focus on sensory memory.

Sensory memory is the idea that most of what you experience through your senses is temporarily stored in a memory system that allows you to access it. The vast majority of information is lost from this system, but some of it is attended to and passed on to short-term and then long-term memory. Here is a quick illustration of the three main systems/types of memory and the way they interact (Atkinson & Shiffrin, 1968).

The existence of sensory memory was shown experimentally by George Sperling in 1960. Sperling presented subjects with 3 x 3 matrices of letters and asked them to recall (freely) as many as possible. Most subjects could recall 4-5 letters at a time. This result was fairly well known at the time and was nothing new. Sperling tweaked the experiment and had the subjects perform a cued recall. Following the presentation of the 3 x 3 matrix of letters, a second screen was presented with one location of the 3 x 3 matrix cued. Subjects were supposed to remember the specific letter that corresponded to cued location. Surprisingly, subjects were quite good at this. According to Sperling, the entire visual field had been placed into sensory memory and so any of it could be remembered via a cue. If you just ask subjects to recall freely (with no cue), they cannot remember all of the letters because by the time they have remembered a few of them, their sensory memory of the other letters has disappeared.

In his book, Baddeley discusses the existence of a visual sensory memory (called an iconic memory) and of an auditory sensory memory (called an echoic memory). This is the first place in the book where I found information related to different sensory modalities. Iconic and echoic memory systems are focused on different modalities (visual and auditory, respectively). Does the existence of these memory systems provide evidence in support of VARK? Well, VARK theories depend on individual differences in modality abilities. They believe that some people are better visually and other aurally. Is there any evidence to support this notion from the discussion of sensory memory in Baddeley’s book?

In short, no.

Baddeley (1984) has no discussion of whether individual differences occur between iconic and echoic memory systems. Baddeley does discuss differences between these systems, but suggests that these differences are more universal:

“The existence of a rather more durable auditory memory system can be shown as follows. Suppose I were to read out to you a series of nine-figure telephone numbers, The chances are that you would get most figures of each number right, but would tend to make errors. If I then switched to a system of presenting the numbers visually, one figure at a time, you would find that you made rather more errors, particularly towards the end of the sequence…. A sequence of spoken numbers is better remembered than a sequence of numbers presented visually because auditory sensory memory appears to be more durable that visual.”

From Baddeley (1984). The number of errors made is graphed above. The dark curve is for iconic memory and the light curve is for echoic memory. As you can see, people make more errors in iconic (vsual) memory towards the end of a sequence compared to echoic (auditory) memory.

To be completely honest, there is one place in his discussion of sensory memory where Baddeley mentions some individual differences. He discusses the length of time that subjects are able to hold something in auditory sensory memory and says: “…subjects vary somewhat in their capabilities, but on average can detect repetitions separated by up to three seconds, indicating an auditory memory system of at least this duration.”

Is this brief mention of individual differences in echoic memory evidence for VARK theories? I don’t believe so. Baddeley is saying that some people have longer temporal capacities for their echoic memories, but he does not discuss that the iconic memory system may compensate for this in some patients. For these data to support VARK theories, some subjects would have to demonstrate better iconic memories than echoic memories and vice versa. Instead, according to Baddeley, we universally see a more “durable” auditory sensory memory system compared to visual sensory memory. We just see slight differences in the capabilities of everyone’s auditory sensory memory.

References

Atkinson, R. C., & Shiffrin, R. M. (1968). Human memory: A proposed system and its control processes. In K. W. Spence (Ed.), The psychology of learning and motivation: Advances in research and theory (Vol. 2) (pp. 89-195). New York: Academic Press.

Baddeley, A. (1984). Your Memory: A User’s Guide, England: Penguin.

Sperling, George (1960). "The information available in brief visual presentations". Psychological Monographs 74: 1–29.