Productivity experts have long debated the efficiency of multitasking. Some scientists, however, have wondered if multitasking is even humanly possible. 

According to a recent TED-Ed video, the science is clear: your brain simply doesn't have the energy to hold two or more thoughts in unison. This is different from the way that Inc. writer Adam Vaccaro recently discussed multitasking. Some people multitask by switching back and forth between different tasks in a given time period. As Vaccaro pointed out, this can actually be good for productivity

But in studying how the brain uses energy, scientists have learned that it's virtually impossible to do two things at once with equal amounts of attention. 

That's because the human brain itself needs to consume large amounts of energy just to survive. "Half the calories a brain burns go towards simply keeping the structure intact by pumping sodium and potassium ions across membranes to maintain an electrical charge," according to the video. 

"The high cost of maintaining resting potentials in all 86 billion neurons means that little energy is left to propel signals down axons and across synapses--the nerve discharges that actually get things done."

And so the rest of your brain functions are supported by a fixed proportion of energy. But that doesn't necessarily suggest that the brain is inefficient. It just means that a lot of what the brain does happens outside of a person's consciousness.

You can watch the entire video below to learn how it works.