Do you find that just the smell of your coffee is enough to perk you up in the mornings? You might not be imagining it, because a new study into the effects of the aroma of coffee has found that it can sharpen the brain in certain circumstances.

Specifically, researchers split 114 students into two groups to answer maths questions from the Graduate Management Admission Test (GMAT). One group was exposed to a coffee smell during the test, and ended up with "significantly higher" scores.

What's more, based on questions asked during the test, just smelling the beverage seemed to boost students' expectations for how well they would do.

The researchers think some sort of placebo effect might be happening, where an expected increase in performance ends up leading to an actual increase.

"It's not just that the coffee-like scent helped people perform better on analytical tasks, which was already interesting," says lead researcher Adriana Madzharov, from the Stevens School of Business in New Jersey.

"But they also thought they would do better, and we demonstrated that this expectation was at least partly responsible for their improved performance."

The coffee scent used for the first experiment was free from caffeine and any other stimulants, and was reported as noticeable by 70.4 percent of the group exposed to it.

A follow-up survey, asking questions of 208 individuals not involved in the first test, found that a coffee scent was associated with being more alert and energetic, compared with other scents such as flowers, or with no scent at all.

In this second experiment, no coffee aromas were used, but the participants' mental association between a coffee smell and enhanced responsiveness might be part of the reason why the first experiment went the way it did.

Something must be happening to boost student results in the GMAT test, and coffee's reputation as a stimulant might be it. The placebo effect might be baffling, but plenty of research has shown that it's real.

This is a relatively small study, but it might also help scientists improve their understanding of how smell affects our state of mind. The team behind it wants to extend the research to look at whether smelling coffee might cause someone to stay awake for longer, for example.

The drink continues to be a daily staple around the world, and continues to fascinate researchers too. Coffee can mess up your circadian rhythms and has been linked to an increased cancer risk, but studies have also found it can improve heart health and even help you to live longer.

Now it seems that even just a whiff of coffee can trigger feelings of alertness in the brain. The researchers even speculate that this knowledge could be useful for anyone who is planning a public space or organising a group of people.

"Olfaction is one of our most powerful senses," says Madzharov. "Employers, architects, building developers, retail space managers and others, can use subtle scents to help shape employees' or occupants' experience with their environment."

"It's an area of great interest and potential."

We'll need more research to fully understand if this can happen on a larger scale, and why it happens at all. In the meantime, try walking slowly past your favourite coffee shop tomorrow morning, without buying anything, and see if it sets you up for the day.

The research has been published in the Journal of Environmental Psychology.