Andrade, Kavanagh and working memory

Kavanagh et al. (2001) and Andrade et al. (1997) found support for their hypothesis that working memory theory might explain the effect of eye movements in EMDR. They reported that eye movements (EMs) resulted in a significant decrease in the vividness of memory images and the associated emotion, and that this effect was significantly greater for EMs than those of control conditions such as tapping, complex tapping, fixed gaze, and visual noise.

I think that working memory theory provides, to date, the best explanation for the effects of EMs in EMDR. Working memory is a “limited capacity system allowing the temporary storage and manipulation of information necessary for such complex tasks as learning, comprehension, and reasoning” (Baddeley, 2000, p. 418). You can compare it perhaps to RAM in a computer – it holds information in memory, at the same time that the information is being actively manipulated. Humans have limited working memory capacity. Unlike our computers, we can only hold a small amount of information in working memory. Working memory is thought to have 2 main subsystems – a visual-spatial component (called the visuospatial sketchpad) and a verbal-auditory component (the phonological loop). A person can perform 2 tasks simultaneously when they use different subsystems. We don’t have too much difficulty reading and listening to music, but it is much harder for us to read and listen to words at the same time (at least I hope I’m not the only person who has trouble reading the headlines on CNN at the same time as listening to the news anchors!).

A lot of research has shown that performance will be degraded when individuals try to simultaneously perform two tasks that use the same working memory resources. These findings suggest that because EMs use the resources of the visuospatial sketchpad, they compete for these resources with the visual image that is being held in working memory. The effect of this competition for resources is a degradation of performance – the image becomes less vivid and less emotional. These effects appear to last for a short period of time after the dual task is completed (van den Hout et al., 2001). This explanation for the possible effect of EMs in EMDR was supported in experiments by Andrade and Kavanagh.

I think that it is legitimate to refer to these effects in EMDR as within-session-desensitization. During the EMDR session, the memory image loses its vividness and its emotionality. The client is desensitized, during the process, to the memory. The EM effects may not last after the session, but these effects are used during the session to enhance information processing. The final result is that the memory is fully desensitized and reprocessed.

EMDR is specifically structured to take advantage of, and utilize, these within session desensitization effects. I think that this works in the following way (description is simplified):
1. The client identifies a visual image and its related emotion.
2. He focuses on this while engaging in EMs.
3. The memory image loses its salience (vividness and emotiveness).
4. The therapist asks the client “what do you notice?” This elicits other aspects of the memory, which now are more salient than the original image.
5. The client focuses on these new aspects while engaging in EMs.
6. The new aspects lose their vividness and emotiveness.
7. The therapist asks the client “what do you notice?” This elicits other aspects of the memory.
8. These other aspects in turn are desensitized.
9. Finally, all negative aspects are desensitized and more positive information is elicited. This positive information is integrated into the desensitized memory.

During this process, there is continuing change to the memory as it is desensitized and processed. The final outcome is a desensitized and reprocessed memory, with effects that are maintained. The within session desensitization effects of the EMs are intrinsic to this process.

Replies:

There are no replies to this message.

| Behavior OnLine Home Page | Disclaimer |

Copyright © 1996-2004 Behavior OnLine, Inc. All rights reserved.