“Multitasking” is more accurately described as “task switching” because people typically can’t effectively sustain split attention.
However, it is possible to alternate between two mental tasks, but there is a “cognitive switching cost” in decreased speed and performance accuracy.
One vivid example of performance decrements when performing simple “multitasking” is illustrated in a study of walking while using a mobile phone, conducted by Western Washington University’s Ira E. Hyman Jr., S. Matthew Boss, Breanne M. Wise-Swanson, Kira E. McKenzie, and Jenna M. Caggiano.
In addition, the “multitasking” participants walked more slowly, changed directions more frequently, and were less likely to acknowledge other people than individuals.
Hyman and team concluded, “Doing more than one task at a time, especially more than one complex task, takes a toll on productivity,” and went on to note the dangers of driving while talking on a phone.
In fact, a previous blog reviewed the evidence for reduced driving performance when listening to music, a less-demanding activity than texting or talking on a telephone.
Even switching between two well-practiced languages can reduce cognitive processing speed, found Queensland University of Techology’s Renata Meuter and University of Oxford’s Alan Allport.
They asked bilingual participants to name numerals in their first language or second language in an unpredictable sequence.
Participants responded more slowly when they switched to the other language, indicating a “cognitive switching cost.”
Volunteers named digits associated with a background color in their first language or second language.
They named digits in their second language more slowly, but were slower in their first language after the language changed from the previous cue.
Involuntary persistence of the second-acquired language interfered with participants actively suppressing their original language, leading to delays when responding in their more well practiced “birth tongue,” they argued.
As tasks become more complex, the performance-hampering effects of task switching increase, according to United Stated Federal Aviation Authority’s Joshua Rubinstein with Jeffrey Evans, and David Meyer of University of Michigan, who evaluated switching between different task like solving math problems or classifying geometric objects.
Like Meuter and Allport, they noted that people switching tasks navigate two stages of “executive control:”
- Goal shifting: “I want to do this now instead of that,”
- Rule activation: “I’m turning off the rules for that and turning on the rules for this”.Rubinstein’s team estimated that traversing these phases can reduce productivity by much as 40 percent, and noted that the problem is compounded for individuals with damage to the dorsolateral prefrontal cortex.
However, musical training seems to reduce the costs of task switching, found York University’s Linda Moradzadeh, Galit Blumenthal, and Melody Wiseheart.
This team matched more than 150 similar age and socioeconomic status participants who were also:
- Monolingual musicians (averaging 12 years of musical training) or
- Bilingual musicians (averaging 12 years of musical training) or
- Bilingual non-musicians or
- Monolingual non-musicians.
Volunteers performed task switching and dual-task challenges, along with intelligence and vocabulary measures.
Musicians demonstrated fewer global and local switch costs compared with non-musicians and bilingual volunteers.
This finding contrasts other results regarding bilingualism’s advantage for task switching performance in a previous blog post.
In addition, Moradzadeh’s team found no benefit of combining bilingual expertise with musical training to reduce task-switching costs,
These results suggest that musical training can contribute to increased ability to shift between mental sets in both task switching and dual-task efforts, thanks to “superior ability to maintain and manipulate competing information in memory, allowing for efficient “global” or holistic processing.”
-*To what extent do you find “multitasking” an effective practice to accomplish cognitive tasks?
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