It may sound like a cliché, but for many, the day doesn’t truly start until they’ve emptied their coffee mug. Coffee is frequently associated with boosting alertness, and people swear by it to stay awake and enhance their productivity. However, our brain might actually be lying to us about how much we need that coffee.

A team of Portuguese scientists found that the feeling of alertness people experience after having a cup of coffee might be more of a placebo effect caused by the experience of drinking coffee, instead of the effects of the caffeine itself. In their paper, they describe how they performed MRI scans on people who regularly drink coffee.

“There is a common expectation that coffee increases alertness and psychomotor functioning,” Nuno Sousa of the University of Minho, study author, said in a statement.

“When you get to understand better the mechanisms underlying a biological phenomenon, you open pathways for exploring the factors that may modulate it.”

Is it the caffeine or just the drink?

The researchers recruited participants who drink at least one cup of coffee daily. Before the study, they were instructed to abstain from consuming any caffeinated beverages or food for at least three hours. The team first interviewed them to gather sociodemographic data and then did two MRI scans, one before and one after taking caffeine or drinking a standardized cup of coffee. 

During the scans, participants were asked to relax and allow their minds to wander. Given the neurochemical effects of coffee, the scientists believed that the scans would reveal heightened integration of networks associated with the prefrontal cortex. This part of the brain is involved in executive memory, as well as the default mode network, responsible for introspection.

The findings showed that both coffee consumption and pure caffeine intake led to a decrease in connectivity within the default mode network. This suggests that the act of consuming either coffee or caffeine enhanced individuals’ readiness to transition from a state of rest to engaging in tasks.

However, drinking coffee increased the connectivity within the higher visual network and the right executive control network – regions of the brain linked with working memory and cognitive control. This effect wasn’t observed when participants only took caffeine and didn’t experience the feeling of savoring a cup of coffee.

“Taking into account that some of the effects that we found were reproduced by caffeine, we could expect other caffeinated drinks to share some of the effects,” María Picó-Pérez, study author, said in a statement.

“However, others were specific for coffee drinking, driven by factors such as the particular smell and taste of the drink, or the psychological expectation.”

The authors acknowledged the limitations of their study, mentioning that they didn’t examine whether non-caffeinated coffee could yield similar results to caffeinated coffee. Additionally, they cautioned that the perceived benefits reported by coffee drinkers may potentially be attributed to the relief of withdrawal symptoms, which weren’t looked at in the study.

The study was published in the journal Frontiers in Behavioral Neuroscience.