For the next few posts, I will be discussing a study by researchers François Maquestiaux, Maude Laguë-Beauvais, Eric Ruthruff, and Louis Bherer titled "Bypassing the central bottleneck after single-task practice in the psychological refractory period paradigm: Evidence for task automatization and greedy resource recruitment" published in October of 2008 in the journal Memory and Cognition. This study represents an "aha moment" for me, as I believe I am beginning to understand the extent to which people are capable of performing multiple tasks simultaneously. The article forced this epiphany on me during its literature review section.
While reviewing the history of dual-task research, Maquestiaux et al. mentioned a seminal study titled "The 'psychological refractory period' and the timing of high-speed performance: A review and a theory" that was published in a 1952 issue of the British Journal of Psychology. The author of that study, Alan Welford, observed that the closer to simultaneously that two stimuli are presented, the greater the amount of time it takes for subjects to respond to the stimulus that was presented second. Welford referred to the delayed response to the second stimulus as a "psychological refractory period." Further, he observed that subjects were capable of perceiving multiple stimuli simultaneously and performing multiple responses simultaneously, but something happened between the perception of the stimuli and the performance of the responses that always caused a delay in the second response. From these observations, he inferred that a processing bottleneck occurred in the middle of his subjects' task activities. This bottleneck, he explained, resulted from the brain's need to select a response to each stimulus, and that selection of responses had to occur consecutively, not concurrently.
Another way of looking at this is to say the senses are capable of receiving (and temporarily storing) multiple inputs simultaneously, and the body is capable of performing (and delaying) multiple outputs simultaneously, but the brain only seems to be capable of making one decision at a time. That, in a nutshell, is my "aha moment." I think it's quite an elegant explanation for the observed phenomena. Moreover, that's how my senses, brain, and body "feel" like they work.
As the title for this post series indicates, what I'm interested in now is whether that bottleneck can be bypassed, and if so what the limits are. In my next post, I will discuss the progress that researchers have made toward answering that question by sharing the findings of a few more studies mentioned in the research review of the Memory and Cognition article that led up to the 2008 study; in part 3 of this series, I will share its results.
I'm anxious to get started.
Tuesday, March 31, 2009
Subscribe to:
Post Comments (Atom)
Posts
I have to agree that the bottleneck factor is an elegant solution to that multitasking dilemma and I am curious what bypasses have been found.
ReplyDeleteWhen reflecting on the ideas you present, I keep asking myself how does performance at multitasking related to intelligence, learning ability or developmental stages. In other words, are multitasking abilities a learned or innate skill? It seems that most curriculums, especially within the K-12 area are based on sequentially tasks. If people do have an ability to multitask, would tapping the ability or integrating the idea into curricular methods enhance or detract from learning? Have you come across any examples where learning technologies are embracing methods that require true multitasking and or task switching? If so what were the impacts on learning efficiency? Are technological developments at a point where the ability of humans to task switch is a barrier to future development? I do not expect you to answer these questions as they are issues I consider as I read your post.
I remember seeing a show on the development of an interface for a fighter pilot cockpit. The problem was the pilot was being presented with more information than he could simultaneously process. Because of this “information overload” the developmental goal was to simplify the interface, presenting the pilot with only the information he needed at a give point in time. For instance, the pilot could process more flight information during straight and level flight than during sorties or combat scenarios. As such, an interface was developed that allowed the pilot to focus on the specific situation at hand. The point being that to allow peak pilot performance, the developers focused on interface simplification and the elimination of the need to multitask. Do you believe the trend is to simplify technology as opposed to complicate with multitasking?
Hi Trace,
ReplyDeleteYou always have insightful questions and observations. Thank you.
I've read (indirectly) that higher multitasking ability is associated with higher intelligence. In this post, I described an experiment in which researchers tied "fluid intelligence" to working memory; working memory seems to be a significant facilitator of multitasking. I think a large part of intelligence, especially fluid intelligence, is innate, so I also think that a large part of multitasking ability is innate, too. However, that study suggested that one's working memory can be improved through training, and that the training boosts scores on tests of fluid intelligence, so it might be possible to augment nature with a little nurturing (but I suspect nature would still impose an upper limit that varies by individual regardless of training).
I have read a little bit about the development of multitasking ability. Specifically, young children tend to be poor multitaskers. Then, in late childhood they improve their ability to multitask/task switch until they reach a peak in late adolescence and early adulthood. There is a slow decline until late adulthood, at which time a steeper decline sets in. However, performance varies dramatically by individuals.
In my response to your other comment (on part two of this series of posts), I mentioned that I didn't see much place for multitasking in learning environments because learning is novel and greedy for cognitive resources. I failed to mention, however, a thing called the dual processing model of working memory. One of its predictions is that people can integrate information more efficiently if it is presented in multiple modes simultaneously. For example, a biology teacher could describe the process of mitosis verbally while also providing a schematic illustration of it. If the dual processing model of working memory is accurate, then students would learn better because their visuo-spatial sketchpad (working memory for pictures) and their phonological loop (short term memory for words) would enable them to integrate more information than if they only saw the picture or only heard the words. I don't think perceiving (seeing and hearing) counts as multitasking, especially since it doesn't require response selection.
It's funny that you mention the pilot interface. I just read about a study in which Israeli pilots who played a game called Space Fortress significantly outperformed pilots who did not play the game. The explanation given was that Space Fortress trained pilots to divide (or rapidly switch) their attention among multiple objects with some degree of automaticity, and that their ability to do so translated to improved flight performance.
Thanks again and have a nice evening,
Michael Misha