You may think that coping with challenges in a busy workplace will impress your boss. Both of you, however, might be surprised to learn that juggling your assignments may be making you less, not more, efficient. That’s the conclusion of a study by management experts who looked at the effects of employees having to wear multiple hats on the job.

Different tasks call for different states of mind, called mindsets. Dealing with a troubled child on the phone requires a different mindset than dealing with a customer in your office. You do a better job, the researchers found, when you do as much as you can using one mindset before switching gears to another.

The study measured the ability of workers to perform various mental exercises after spending time switching mindsets to complete different tasks. The effort of switching mindsets seemed to cause people mental exhaustion. People who didn’t have to switch mindsets often performed better on follow-up tests of mental ability.

One drawback of the study was its use of indirect measurements for estimating mental functioning. For example, participants were asked to control their laughter while viewing a comic film. Frequent mindset switching before the entertainment made it harder for the people to suppress their laughter. The conclusions may be strengthened if the results are confirmed using direct measurements of mental abilities.

Switching mindsets, multitasking or trying to do two or more tasks simultaneously, may have other drawbacks. Besides decreasing your efficiency, it can cause poor short term memory and decision making, and may even contribute to weight gain.

If you really want to impress your boss, try doing as much work as you can using one mindset before switching to another. You might be less stressed, more mentally organized, and your improved job performance will be more impressive than your apparent ability to juggle.