Researchers in Portugal set a test to question whether coffee by itself is responsible for alertness or if it's something like its smell or taste in the morning ritual that triggers that.

Nuno Sousa, professor at the University of Minho's School of Medicine in Portugal and one of the study's authors told NBC News, "If you listen to these individuals, they typically say that they need to have coffee in the morning to get ready. We wanted to understand the brain mechanisms and functional connectivity pattern that would justify this claim".

In the research, 83 people drank at least one cup of coffee a day to undergo MRI scans for brain activity tracking. 

47 of the 83 people were scanned before drinking the coffee and then again 30 minutes after. The other 36 were given caffeine diluted in hot water, so no coffee, and underwent the same types of MRI scans before and after.

Published in the journal Frontiers in Behavioral Neuroscience, the study revealed that certain changes in brain activity were due solely to coffee, while others were attributable to caffeine.

Both groups had decreased activity in a part of the brain that puts people in a resting state after drinking, which indicated that after drinking, people were ready to kick off their day. Previous research has already proved that caffeine, a psychostimulant, can make people more alert.

Read next: Coffee, Tea Reduce Rates of Dementia & Stroke

On the other hand, MRI scans displayed that drinking coffee increased activity in parts of the brain that were involved in short-term memory, attention, and focus, which caffeine alone did not do. Therefore, the researchers deduced that coffee's sight, smell, or taste can increase alertness regardless of caffeine amounts. 

"The pleasure that is given to an individual that likes coffee in the morning, that actually is part of almost a ritual that really is also important for that individual to feel that 'I'm ready for the day,'" Sousa stated, adding that those who are not regular coffee drinkers may not experience the same. 

Coffee proven for positive vibes

Adjunct professor of neuroscience at Johns Hopkins University School of Medicine, Mark Mattson who wasn't involved in the research, said to NBC News that this discovery was not surprising because humans form associations with certain sensory experiences over time, influencing reactions.

"It kind of makes sense, right? Coffee has taste and smell, so when you drink coffee, you're activating brain regions that are involved in the perception of the taste of the coffee, the perception of the smell," Mattson said.

Dr. Uma Naidoo, a nutritional psychiatrist at Harvard Medical School, explained to NBC News that positive memories can be triggered by the sight of coffee which can also make someone feel more awake.

All three researchers agree that the natural chemicals in coffee may have independent effects on brain activity, aside from caffeine such as epicatechins in coffee which has been shown to develop memory in animal studies.

Read more: Study suggests coffee drinkers at lower risk of early death