The effects of intoxication were stronger in those who believe that energy drinks boost the effect of liquor, said the study published online in the Journal of Consumer Psychology.
"Red Bull has long used the slogan 'Red Bull gives you wings', but our study shows that this type of advertising can make people think it has intoxicating qualities when it doesn't," said lead author Yann Cornil, Assistant Professor of the Sauder School of Business, University of British Columbia, in Canada.
The study conducted at the Paris-based INSEAD Sorbonne University Behavioural Lab involved 154 young men.
Although all drinks had the same ingredients, they had different labels: Red Bull and vodka, a vodka cocktail or a fruit juice cocktail.
The effect of the label alone on participants' self-assessment of intoxication was remarkable.
Labelling the same cocktail as vodka and Red Bull increased perceived intoxication by 51 per cent, compared to labelling it a vodka cocktail or a fruit juice cocktail.
It also increased the young men's intentions to approach and "chat up" women, and their confidence that they would welcome it.
Finally, it led also to more risk-taking in a gambling game. All these effects were stronger for the participants who most strongly believed that energy drinks boost the effects of alcohol and that being intoxicated reduces inhibitions and increases risk-taking.
This study showed that there is a causal effect of mixing alcohol and energy drinks on perceived intoxication and real behaviours driven by the expectation that energy drinks boost the effects of alcohol, rather than the contents of the cocktails.
According to the researchers, the findings highlight a need for policymakers and consumer protection groups to re-examine how energy drinks are advertised and labelled.