The human brain cannot perform two tasks simultaneously. Although training improves speed, a new study reveals that processing always occurs in sequence: one task at a time.
Many believe that, with enough training, they can multitask. However, a new study calls this belief into question. Even with intensive training, the human brain cannot perform two tasks simultaneously.
Instead, the brain continues to process them sequentially, according to a study in Quarterly Journal of Experimental Psychology from the Martin Luther University of Halle-Wittenberg, the University of Hagen and the Hamburg School of Medicine.
For the research, participants performed two tasks in parallel: they had to indicate with their right hand the size of a circle that appeared briefly on a screen and, at the same time, say whether a sound emitted was high, medium or low. Response speed and the number of errors made were measured. The tests were repeated over several days.
More speed is not multitasking
With practice, participants became faster and made fewer mistakes. For a long time, this training effect was considered an indication that, with enough practice, the brain can process tasks in parallel.
“This phenomenon, known as ‘virtually perfect time sharing,’ has long been considered proof of true parallel processing in the brain and evidence that the human mind has an unlimited capacity for multitasking,” said psychologist Torsten Schubert of Martin Luther University.
However, the new results contradict this assumption.
Optimization with limits
According to researchers, the brain optimizes the order of the various processing steps so that they interfere less with each other.
“Our brain is very skilled at chaining processes together,” explained Schubert. However, this optimization has its limits.
The research team was also able to demonstrate that even the smallest changes to tasks increased the error rate and caused participants to take longer to complete them.
The conclusions are also relevant for everyday life: multitasking can become a risk, for example, when driving or in professions with many tasks at the same time, noted psychologist Tilo Strobach, from the Hamburg School of Medicine.
