Multitasking also hits limits with practice, study finds - New study debunks the myth of true human multitasking

A new study has cast doubt on the idea that humans can truly multitask. Researchers from Martin-Luther-Universität Halle-Wittenberg and FernUniversität in Hagen found that even with practice, the brain struggles to perform two tasks at the same time. The findings suggest that what seems like multitasking is actually the brain switching rapidly between tasks, not processing them in parallel.

The study involved 25 participants across three experiments. Each person used their right hand to indicate the size of a briefly displayed circle while simultaneously classifying a tone as high, medium, or low. The goal was to test how well the brain handles dual tasks over time.

Participants improved with training, becoming faster and making fewer mistakes. However, even small changes to the tasks—like adjusting the routine—led to more errors and slower reaction times. This showed that the brain optimises the order of processing steps to reduce interference, rather than handling both tasks at once. Previously, the concept of 'virtually perfect time-sharing' was seen as proof that humans could process two tasks in parallel. But this research challenges that assumption. The results highlight that, despite practice, the brain still works through tasks one after the other. The findings have real-world implications. Multitasking can be risky in situations like driving or jobs that demand constant task-switching. Even minor disruptions can slow performance and increase mistakes.

The study confirms that the human brain does not truly multitask. Instead, it quickly shifts between tasks, even after extensive practice. These results underscore the limits of multitasking and suggest that small changes in routine can still disrupt performance.