Dual-Task Interference: A Personal Driving and Reading Experiment

Introduction and Experiment Design

The two-channel experiment I attempted involved driving and reading. Both of these actions are decidedly conscious. However, to establish a primary and a secondary action — or "stream" (Baars, 1997, p. 39) — I chose to drive an exceedingly familiar route: from my part-time job to home. This is a lengthy journey requiring a minimum of 35 minutes. Moreover, I engage in it daily during most of the summer and am thoroughly familiar with the surroundings on both sides of the vehicle. More importantly, I have been driving this particular car for the past two years. As such, its novelty has worn off. I am well acquainted with all of the controls, the gadgets, and the levers needed to operate it, so that in this experiment, driving functioned as a control of sorts — a task that, while conscious, is closer to involving the unconscious mind.

The novel action I engaged in was reading. Although I am a good reader, I tested myself by reading a piece of literature I had never before encountered — a lengthy article from an arts and entertainment magazine. I was able to read this article intermittently while simultaneously, and largely unconsciously, gauging the distance of other vehicles and monitoring my surroundings while driving on the freeway at a moderate speed of 55 miles per hour. I attempted to focus on the magazine article as much as possible while still driving safely. Because the subject of the article was music, I was thoroughly engaged with it — far more so than with driving. To assist with the driving aspect, I set the car on cruise control and maintained 55 miles per hour in the second lane in order to avoid oncoming and outgoing freeway traffic.

Reactions and Behavioral Findings

I was able to drive home without getting into any sort of automobile accident, which was a relief. This fact, which is empirically observable given the pristine condition of my automobile, constitutes an external, behavioral finding. Behavioral analysis helps to explicate the "complexities of human behavior" (Vilardaga et al., 2009, p. 106). Internally, however, I was able to recall very little of my journey home. Once I began reading, I did not notice any of the familiar sights along the side of the road that I typically observe when driving home.

Another empirically based, external behavioral finding related to the driving was that my behavior attracted the attention of two other drivers, as explicitly indicated by them honking their horns at me. One driver was operating a large truck who, after coming up behind me, passed me — he may have been honking because I was driving so slowly. Another man in a nearby vehicle pulled up alongside me and honked his horn several times to get my attention, then waved his finger in a disapproving, "don't do that" manner before driving on. The social perception of these individuals (Davis and Lennon, 1988, p. 176) was not aligned with mine at the time, although I was aware of them.

In terms of my ability to comprehend, internalize, and retain the information I had read in the article, my capacity to do so was extremely limited. I was familiar with the main idea — the particular music artist the article focused on — and basic facts, such as the fact that he had recently released new work. But I was unclear about many details: the name of the new release, and the relevance of certain quotations from the artist to the surrounding text. I read the same article again once I got home and noticed several details I had more or less skimmed over while driving. I had not attempted to skim them; I had simply read the words without fully comprehending them in their proper context — something I was able to do once I was home.

Relationship of Findings to the Readings

My findings seem to correlate considerably with the academic concept known as dual-task interference, defined as "people's ability (or inability) to perform two or more tasks concurrently" (Pashler, 1994, p. 220). It is worth noting that the two tasks involved in this experiment do not necessarily require the same type of human engagement — driving involves both physical and mental capacities, whereas reading pertains to the mental alone. In general, my findings were consistent with the psychological refractory phenomena (PFP), in which, when performing dual tasks, "the response…becomes slower when the interval between the stimuli is reduced" (Pashler, 1994, p. 222). In my experiment there was no interval between the stimuli; they occurred simultaneously. Nevertheless, both tasks proceeded at a slow pace. I typically drive home at 70 miles per hour, and it does not usually take me the better part of 35 minutes to complete a single article. Yet, when the two drivers honked their horns at me, my reading slowed considerably — actually stopped — while I concentrated on driving to determine what the other drivers wanted.

It also appears that my difficulties with memory retention and detailed comprehension of the article reflect the kinds of difficulties discussed in Pashler and Johnson's work related to "memory storage and memory retrieval" (p. 156). I could engage in the minimal physical component of reading — my eyes would focus on letters and discern words from them. Yet the trouble I had in producing meaning from those words, as well as establishing connections between them and the surrounding context (not to mention recalling these elements of the article afterward), confirms that in the realm of memory retrieval, "a…more central form of limitation seems to arise" (Pashler and Johnson, p. 184).

References

Baars, B. (1997). In the Theater of Consciousness: The Workspace of the Mind. San Diego: Oxford University Press.

Davis, L. L., & Lennon, S. J. (1988). Social cognition and the study of clothing and human behavior. Social Behavior and Personality, 16(2), 175–186.

Pashler, H. (1994). Dual-task interference in simple tasks: Data and theory. Psychological Bulletin, 116(2), 220–244.

Pashler, H., & Johnson, J. C. (no date). Attentional limitations in dual-task performance.

Ruthruff, E., Van Selst, M., Johnston, J. C., & Remington, R. (2004). How does practice reduce dual-task interference: Integrating, automatization, or just stage-shortening? Psychological Research.

Vilardaga, R., Hayes, S. C., Levin, M. E., & Muto, T. (2009). Creating a strategy for progress: A contextual behavioral science approach. The Behavior Analyst, 32(1), 105–133.