Multi-tasking hinders performance--study

Delving into how the human brain operates, the study found that it is designed to administer two chores at a time.

When it comes to multi-tasking, the brain tends to slow it down. The reason lies in the part of human brain called the medial prefrontal cortex that divides into two parts when organizing tasks and the order in which they are performed.

When two tasks are at hand, the brain executes the work by efficiently switching between the tasks. However, an additional task results in fumbling and distraction may occur.

Dr. Etienne Koechlin, director of the cognitive neuroscience laboratory at the French National Institute for Health and Medical Research in Paris and lead researcher on the project stated, “In terms of everyday behavior, you can cook and talk on the phone at the same time.

“The problem arises when you pursue three goals at the same time. Your prefrontal cortex will always discard one.”

Multi-tasking skills in 32 persons assessed
In a bid to determine whether multi-tasking overwhelms the human brain, the researchers monitored 16 women and 16 men, aged 19 to 32, as they performed a complicated letter-matching task.

The volunteers were observed with functional magnetic resonance imaging while doing the work. Volunteers received money rewards for the number of letters matched without error.

Findings of the study
When the 32 subjects performed the initial task, both sides of their brain were active. The second task involved matching uppercase letters and lowercase letters with each of the two tasks had separate reward structures.

On taking the second task, their brains split the labor, the left side of the prefrontal cortex took over the main task while the right side took over the secondary task.

However, when a third task of matching letters of the same color was added, the brain got jumbled and the subjects slowed down consistently forgetting one of their tasks.

The rate of errors tripled establishing that the brain is unable to efficiently perform more than two functions at a time.

Koechlin stated, "The two frontal lobes, which jointly drive the pursuit of a single goal, divide for driving concurrently the pursuit of two independent goals.

"This finding suggests that the human frontal function is limited to accurately driving the pursuit of two concurrent goals at one time.

"This capacity limit places a severe constraint bearing upon human higher cognition and may clarify several limitations in human decision-making and reasoning abilities."

The study is published in the journal Science.