Response Selection Multitasking Bottleneck: Can it be bypassed? Part 2

In the yesterday's post, I summarized the conclusions of a seminal study that helps explain the extent to which people can perceive multiple stimuli, select multiple responses, and perform multiple actions concurrently--i.e. to multitask. In the cases of perceiving and performing, it appears people can multitask. However, in the case of selecting responses, it appears people cannot multitask. Response selection is said to be a bottleneck in the multitasking thoroughfare.

Assuming that model is correct, one alternative to explore is whether it's possible to bypass response selection. A commonly pursued route to bypass response selection is automatization through training and practice. According to the literature review of the October issue of the journal Memory and Cognition article titled "Bypassing the central bottleneck after single-task practice in the psychological refractory period paradigm: Evidence for task automatization and greedy resource recruitment," several studies have been performed to determine the feasibility of training people thoroughly enough that they can bypass it (Maquestiaux et al.). As often seems to be the case in soft sciences like psychology, the evidence is not clear, but the general trend hints it is possible under certain conditions.

In the 1960's, at least three studies were conducted to discover whether subjects could be trained well enough that they would generate responses automatically without the need to select one. The results of all three studies were negative--automatization was not achieved by any of the subjects. Maquestiaux et al. believe the one confounding factor that needed to be controlled in those studies was their reliance on subjects producing manual responses, rather than a combination of verbal and manual. In 1999, a study by researchers Van Selst, Ruthruff, and Johnston showed that allowing for verbal responses enabled subjects to nearly eliminate the response delay, but it was still there--except for one subject. That subject participated in another study in 2003, and it was found that the reason the delay was not observed was because the perception time for the second task happened so quickly that it was able to be processed before the first task, thus there was no delay observed for the performance of the second task. When the order of the tasks was reversed, the delay materialized. So the bottleneck was still there. In the last 8 years, additional studies have controlled for the confounding factors of the previous studies, and some have shown the bottleneck to have been bypassed. Maquestiaux et al. point out, though, it may be that the response delays are just small enough to escape detection by the equipment being used to take the measurements (among other experimental design flaws).

In 2006, researchers named Ruthruff, Van Selst, Johnston, and Remington conducted a study in which 4 out of 18 subjects appeared to bypass the response selection bottleneck--even though all of the aforementioned design weaknesses were controlled for. However, those 4 subjects were only successful in one of two sets of trials. One explanation for the subjects' failure in one experiment but success in another is that the one of the tasks exhibited a "greedy" nature when it was presented first. Ruthruff et al. hypothesized that even though the greedy task could be performed automatically, it had the property of monopolizing all processing resources if it was perceived first, but it would revert to automatic processing if it was perceived second.

With all of that background out of the way, I will be ready to discuss Maquestiaux et al.'s study in my next post. In Maquestiaux et al.'s study, they attempt to determine the correctness of Ruthruff et al.'s hypothesis that certain tasks are greedy, thereby also determining whether or not tasks can be automatized (and bypass the response selection bottleneck) as long as the greedy task is presented second.

I know you're as excited as me to find out the conclusion of this nailbiter, so stay tuned!