Drink think: Why expectation is alcohol's most potent mixer

People's prior beliefs about alcohol can strongly influence how they act when intoxicated – and even change their behaviour when they're sober, writes David Robson.

As the holiday season approaches, many people will be celebrating with an extra glass or two. Whether you drink yourself, or simply observe others, you won't need me to explain the consequences. For some, it will be quiet relaxation, for others, extreme extroversion. It may be a trope of TV and movies that the anxious wallflower turns into the outrageous party animal with a single martini, but many of us will know someone who plays that role in real life too.

And that is something of a scientific mystery, since the biological action of ethanol – the active chemical in alcoholic drinks – simply shouldn't have those kinds of effects. "In terms of its neurochemical properties, ethanol is a central nervous system depressant," explains Andrew Lac, a psychologist at the University of Colorado Colorado Springs. "But when people consume alcohol, they often experience stimulant effects." They become loud, boisterous, and even antagonistic, "which is the opposite of what you might expect".

To resolve this mystery, researchers such as Lac have started to examine the ways that beliefs shape the feelings of intoxication and their influence on behaviour. It seems people may associate alcohol with certain experiences, creating a kind of drunken self-fulfilling prophecy. And in many situations their mindsets may be more potent than the alcohol itself.

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This idea that beliefs could powerfully shape the effects of intoxication may sound surprising. As I describe in my forthcoming book The Expectation Effect, however, our mindsets are shaping almost every other element of our lives.

The most well-known example may be the placebo effect, in which the beliefs of a treatments' efficacy can bring about its own benefits – such as lowering blood pressure, reducing inflammation, or prompting the brain to release its own pain-killing opioids – that are independent of the drug's chemical effects.

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Beyond medicine, we now know that our expectations can influence the benefits of our workouts, our reactions to a new diet, our experience of insomnia and jetlag, the impact of stress and anxiety, our willpower and even our longevity.

Given the sheer prevalence of expectation effects, it would be highly surprising if our beliefs didn't somehow shape our reactions to booze.

The hot sauce challenge

Some of the most compelling evidence comes from Laurent Bègue at the Université Grenoble Alpes in France. In the late 2000s, he set up an intricate experiment to test people's aggression under the influence of alcohol, under the guise of a fake taste-testing.

The participants were first given a set of three cocktails. For some participants, they were completely alcohol-free, while for others, they contained either moderate or high levels of alcohol. Importantly, the participants did not necessarily know which one they were receiving: someone who thought they were receiving the high-alcohol drink may have actually received the non-alcoholic version, for instance. (To stop the participants from guessing the alcohol content, they were told that the mocktail had been designed to have the same taste as the real thing.) This allowed Bègue to manipulate their expectations of intoxication.

To test feelings of aggression, the participants were put into pairs and asked to season a plate of mashed potato with hot sauce and salt, which would be served to their partner. Unknown to the real participants, the partner was really an actor assuming a deliberately hostile persona – kicking their chair on the way into the room and threatening to "blow [their] head off" with the seasoning. The participants, of course, could get their revenge by making a particularly nasty dish in return.

Overall, it was the participants who believed they had drunk the potent cocktails who were likely to dish out the most hot sauce to their companion, while the actual alcohol content mattered much less – evidence of a clear expectation effect influencing their intoxicated behaviour.

Bègue says that the association between alcohol and aggression may emerge early. "Eight-year-old children were asked what the consequences would be if they drank alcohol compared to ice tea," he says. "They answered that alcohol would lead them to abuse others verbally and to fight more."

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Bègue has since tested the ways that our expectations can influence the sense of self-assurance that often comes with intoxication. Like the first study, the participants were given cocktails that may or may not have been correctly labelled with their alcohol content. The participants then were asked to write and film a short advert for the beverage. Finally, they had to watch the footage and rate how attractive, original and funny they had been – an exercise that many sober people may find cringe-worthy.

Once again, it was the participants' beliefs about their alcohol consumption that determined their responses. Those who expected to feel drunk gave themselves higher ratings than those who believed that they were still sober, while the effect of the alcohol content itself was not significant.

Does Red Bull give vodka wings?

Some highly specific expectation effects may depend on the particular type of tipple people consume.

A few years ago, Yann Cornil at the University of British Columbia wanted to investigate whether mixing energy drinks and vodka can really increase intoxication – as many people report anecdotally.

Cornil first questioned participants about their use of alcohol and energy drinks and their expectations of the drink's effects. He then offered them a cocktail, labelled either as "vodka-Red Bull", "vodka cocktail", or "exotic fruits cocktail" – and asked them to complete further questionnaires and tests that measured their experience of intoxication.

Echoing Bègue's results, Cornil found that the labels significantly changed the participants' experiences. If they were told they had drunk the vodka-Red Bull concoction, the participants reported feeling more inebriated than those who had tasted the "vodka" or "exotic fruits" cocktails.

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The average size of that effect was large, with the labels causing a 50% difference in perceived intoxication. But there was significant variation between individuals, which seemed to depend on their pre-existing beliefs. If the participant had arrived at the lab with the assumption energy drinks can increase alcohol's effects, they showed a much stronger reaction to the label than those who did not believe the urban myth.

Similar patterns could be seen on a test of risk-taking. The participants had been given a computer game in which they had to pump up a virtual balloon. The bigger the balloon became, the more money they could win – but if they pumped too hard and it burst, they would lose everything. Believing that they had taken the vodka and Red Bull mix, the participants were much more likely to push their luck – but only if they already expected energy drinks to increase their drunkenness, and their drunkenness to increase their risk-taking.

"The salience of the energy drink created psychological expectations, which translated into a subjective sense of intoxication, and that had behavioural consequences," Cornil says.

Under the influence (of expectation)

Bègue's and Cornil's experiments offer important proof of principles, but they could only capture a moment in people's lives.

One of Lac's recent papers has, however, charted the role of expectation in people's drinking behaviours over the longer term. In a large survey, he recruited more than 400 participants in the US, aged 18 to 79, and asked them to rate a series of statements on a numerical scale of 1 (disagree) to 4 (agree). You can see a few examples below.

When I drink alcohol, I expect that:

• I would feel courageous
• I would feel calm
• I would feel sexy
• I would act sociable
• I would take risks
• I would be loud, boisterous or noisy
• I would feel moody

One month later, he followed this up with detailed questionnaires about their alcohol use and their experiences during those 30 days.

Perhaps unsurprisingly, the expectations influenced how much people consumed: if the participants had more positive associations with alcohol, they were likely to drink a bit more. But the expectations also had an independent effect on the participants' behaviour. If someone thought that the alcohol made them relaxed and sociable, they found that they felt less tense and had higher self-esteem. And if they thought they might become boisterous and risk-taking, then they noted that they acted in more extreme ways that were out of character. As Lac puts it: "these beliefs serve as mental filters that guide what happens after we drink".

In most cases, the expectations mattered as much, if not more, than the actual amount consumed – just as Bègue's and Cornil's laboratory experiments had shown. "It suggests that a lot of the consequences incurred by alcohol use are really not due to the neurochemical properties," says Lac.

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The power of alcohol expectations in daily life could also be seen in a recent study by Christine Lee at the University of Washington and Melissa Lewis at the University of North Texas, who asked students to complete surveys about their expectations and drinking behaviour through thrice-daily telephone interviews over two weeks. They concluded that "one's expectations about the particular effects of alcohol tend to be self-fulfilling for subjective effects of alcohol, even when they are not directly tied to the physiological effects of effects." Those subjective effects included the positive benefits – feeling relaxed and being in a better mood – as well as the downsides of "becoming aggressive rude or obnoxious, and embarrassing oneself."

Mocktail or vinocebo?

It's worth emphasising that these studies have mostly looked at moderate drinking among healthy populations. Those with serious problems need to get professional support, and it will take more than a shift of alcohol beliefs to change damaging behaviours.

Based on my research for The Expectation Effect, however, I hope that a greater awareness of these results could contribute to a healthier lifestyle for people who enjoy the odd drink or two but would like to cut back.

It's certainly caused me to question my relationship with alcohol. Like many other people, I often drink to aid my relaxation and because I feel it will help to lubricate social situations. Having learnt that those positive effects largely come from my expectations, however, I've started to wonder whether I could somehow change my mindset, so that I enjoy the same benefits with fewer units, and without any of the negative effects.

You may be sceptical that this could work without some form of deception, but recent research suggests this may not be necessary. When people have been educated about the placebo response, for instance, they can experience significant pain relief from "open-label" dummy pills that do not attempt to hide the fact that the substance is inert. It seems that knowledge of expectation effects, and their scientific basis, can itself produce a shift in mindset that is quite potent.

While I haven’t decided to become tee-total, I'm experimenting with small measures to reduce the quantity that I drink – choosing a spritzer rather than a full glass of wine, a mocktail instead of a martini, or a low-alcohol beer. If I have something that feels like a celebration and treat, I often enjoy the same glow that I would have experienced with my normal tipples. And when I wake up hangover-free the next day, I thank myself for my choice.

All the fun without any of the downsides, all from a shot of positive thinking? I'll happily raise a glass to that.

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David Robson's book The Expectation Effect: How Your Mindset Can Transform Your Life will be published in the UK on 6 January 2022, and in the US on 15 February 2022. He is @d_a_robson on Twitter.

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