Alcohol has been a major factor in decision-making throughout history and often gives rise to our most (and sometimes least) memorable stories. With a multifaceted influence on society, health, and history, the effects of alcohol on the human body and mind have been a focus of research for many years. Alcohol affects every person differently, and scientists strive to understand how through a variety of studies.

Behavioral Tolerance versus Physiological Tolerance

In popular culture, behavioral tolerance and physiological tolerance are often confused under the term alcohol tolerance. Physiological alcohol tolerance depends on alcohol’s effects on physical markers, such as heart rate, while behavioral alcohol tolerance refers to how intoxicated a person acts using cognitive and motor skills tests. Oftentimes, behavioral alcohol tolerance also takes into account a person’s rating of how intoxicated they feel, making these levels subjective [1]. Behavioral alcohol tolerance differs from physiological alcohol tolerance in that a person’s blood alcohol content (BAC), a quantifiable measure of alcohol in the bloodstream, affects physiological bodily processes, whereas behavioral tolerance falls on a psychological spectrum [2].  

Behavioral Tolerance Theory

In 1943, Kurt Lewin, a social psychologist, published an analysis of a prominent trend in psychological research: that of “group action” [3]. Group action refers to the principle that a person’s behavior is influenced significantly by the behavior of the people around them and by societal norms. Under the group action theory, a person’s behavior in a group context can be vastly different from behavior during an independent experience [3]. Based on this idea, researchers began to more carefully assess how a person’s drinking history, surroundings, or other factors could influence their behavioral tolerance to alcohol.

From these questions, researchers became curious about the associations people have while under the influence. This research built off of Pavlov's famous experiment that involved ringing a bell before offering a dog a treat, thus teaching the dog over time to expect the treat immediately following the sound of the bell. After repeating this practice enough, the dog would salivate whenever it heard the bell, whether a treat was present or not. Pavlov concluded the dog treat (called the unconditioned stimulus because it automatically elicited salivation) could be associated with the ringing of the bell (called the conditioned stimulus) through repetition. This results in a subject’s conditioned response to the stimulus (salivation). Pavlov demonstrated that the unrelated, unconditioned stimulus could trigger the dog’s response, and his findings continue to shape psychological studies to date. Based on this experiment, a hypothesis later arose that alcohol could act as an unconditioned stimulus in Pavlov’s framework of conditioning [4].

Considering alcohol as a possible unconditioned stimulus intrigued the research community and eventually gave rise to a theory about alcohol consumption as a possible conditioned response to social pressure [5]. The theory framed social pressure, rather than alcohol directly, as the conditioned stimulus. Social expectations to act a certain way when inebriated would condition a behavioral tolerance through reinforcement from peers and surroundings that accompany specific behaviors when drunk—meaning a person may act more intoxicated with less alcohol due to social pressure [5]. Additional research suggests a higher behavioral tolerance corresponds with people seeking more alcohol to reach intoxication [6][7]. In other words, a person who is accustomed to consuming a certain amount of alcohol, causing an expected set of behaviors, may develop a tolerance to the amount of alcohol consumed after repeated use. That person would then seek out more alcohol to achieve the same behavioral effects as before, perceiving themselves as tolerant to the amount of alcohol ingested instead of considering the behavioral response to alcohol in a social setting. The findings, with respect to Pavlov, suggest that there is no concrete baseline for how intoxicated a person ought to act when drinking alcohol because experiences with social pressure are variable.

Environmental Cues and Behavioral Tolerance

Reaching beyond the effects of social norms, other studies explored how environmental cues could exacerbate the behavioral tolerance response while drinking. Two independent research groups conducted experiments to examine responses to environmental and situational cues that garnered similar results [8][4]. In both experiments, people drank a series of either alcoholic or soft drinks. Initially, alcohol was consumed in a bar or lounge setting that is typically associated with alcohol, and soft drinks were always consumed in a separate office-based setting. Each person’s heart rate and cognitive vigilance (the ability to concentrate) were tested. Overall, when subjects drank alcohol in the bar, they performed worse on the cognitive tasks than when they drank soft drinks in the office.

However, when the settings for drink consumption were reversed, the results on the cognitive tasks changed drastically. Subjects performed much worse on the cognitive tasks after having consumed alcohol in the office setting than they had after consuming alcohol at the bar. Additionally, consuming alcohol in the office raised heart rates more than in the bar [8][4]. One of the studies also found that when subjects drank soda in the bar setting, they performed better on the cognitive vigilance task than when they consumed soda in the office environment [4]. These results point to a behavioral tolerance response dependent on the environment. Essentially, the subjects would internally and pre-emptively counteract the effects of the alcohol when they were in an environment in which alcohol was expected.

These two experiments were not the only studies involving environmental factors and behavioral tolerance. Overall, most studies agree that any association between an environment and regular consumption of alcohol has a similar effect. It is not enough for a location to have stools and a mirror or other aspects typical of a bar; rather, it is only that the subjects recognize their surroundings as a place where they would expect to consume alcohol.

To build on this, a 1997 study took a closer look at cues possibly sent by the presence of alcohol itself. The researchers offered two groups of people an alcoholic drink of equal strength and then tested them with cognitive tasks and a self-evaluation of their levels of intoxication [9]. One of the groups drank beer while the other drank a bright blue peppermint mixture. The group with the more clearly recognizable alcoholic drink performed significantly better on cognitive tasks than subjects in the group with a beverage not easily recognized as alcohol. The group drinking beer also rated themselves significantly less intoxicated than the group drinking the blue beverage, demonstrating that subjects displayed a higher behavioral tolerance when given alcohol in a recognizable form and felt more affected by alcohol when it wasn’t familiar [9].

Meanwhile, another branch of research into the behavioral response to alcohol consumption questioned why individual responses to alcohol could vary so widely. Researchers attempted to tackle this question by collecting and synthesizing existing research on “alcohol myopia,” the narrowing effect alcohol has on attention and perception [10]. The variation amongst individual responses to alcohol was tied to alcohol’s inhibition of a person’s ability to respond to environmental cues. Individual studies explored alcohol’s effect on subjects’ abilities to recognize many situational cues, or cues that inform a person’s responses to the environment, at the same time. Overall, research showed that alcohol limits the number of cues we can process at once and the amount of information we can extract from cues once we notice them. Interestingly, while immediate, salient cues were still apparent to the subject, secondary cues that might inhibit a person’s emotional behavior in sober situations were not perceived under the influence of alcohol [10].

Placebo Effects on Behavioral Tolerance

Further studies, including many at the University of Washington, explored the behavioral effects of perceived alcohol consumption. A 1990 study involved giving beverages to four different groups of people [11]. Similar to the studies mentioned above, one group drank alcohol in an alcohol-related context (a lounge-style bar), while a second drank non-alcoholic beverages in a context not associated with alcohol (an office setting) [11]. However, the experiment also included a third group of subjects who were told they were drinking alcoholic beverages and were placed in the bar setting, but in reality they were given non-alcoholic substitutes. A fourth group was subjected to the opposite conditions, and thought they were drinking non-alcoholic beverages in the office setting, but were really consuming alcohol. In this experiment, researchers observed that while the first two groups behaved as expected, the third and fourth groups had behavior that matched their perceptions rather than the actual drinks they consumed. That is, the group drinking non-alcoholic beverages in the bar was rowdy and social, acting as if they were drunk, and considered themselves intoxicated. On the other hand, the group unknowingly drinking alcohol did not exhibit the social behaviors commonly associated with drunkenness. They remained quiet and considered themselves sober. The group unknowingly ingesting alcohol did have issues with motor control and cognitive tests, but when interviewed, subjects claimed this performance must be a result of them being tired or not eating well before the experiment—they provided alternative explanations for lackluster performance. This study lends strong support to the hypothesis that a person’s perception of alcohol consumption determines their level of intoxication, rather than the actual amount of alcohol consumed [11].

Current research into behavioral alcohol tolerance continues to seek answers to how complicated social cues and societal standards influence a person’s reaction to alcohol and other addictive drugs. One recent study found that subjects’ self-assessment of their level of intoxication is more closely tied to cues derived from the drunkenness of the people around them than it is to their own functionality [12]. When drinking around sober people, subjects were more likely to consider themselves dangerously intoxicated or unfit to drive, whereas drinking around other inebriated people corresponded with the subjects’ carefree attitude about their own health; they also considered themselves less severely intoxicated after consuming the same amount of alcohol [12].

Conclusion

Over the course of the last two centuries, our understanding of alcohol’s real effect on our brains, and subsequently on our behavior, has become much more accurate and nuanced than before. The research community has extensively probed the addictive properties of alcohol and the mechanisms by which it influences neurochemistry and behavior. Though our grasp of alcohol’s effects on us and its interplay with societal standards and individual perception has grown enormously, there still remains much to be uncovered. Beyond all the questions that have yet to be answered, there are many more that have yet to be asked. As we delve deeper into how alcohol truly holds its power over people, we can only hope to apply new understandings of behavioral tolerance and expand them beyond the sphere of alcohol into other addictive drugs, general societal standards, and patterns of group behavior.

References

1. National Institute on Alcohol Abuse and Alcoholism No. 28 PH 356 April 1995
2. Stewart, J. and A. Badiani. "Tolerance And Sensitization To The Behavioral Effects Of Drugs". Behavioural Pharmacology 1993; 4(4): 289-312.
3. Lewin, K. (1944). The dynamics of group action. Educational leadership, 1(4), 195-200.
4. Shapiro, A. P., & Nathan, P. E. (1986). Human tolerance to alcohol: The role of Pavlovian conditioning processes. Psychopharmacology, 88(1), 90-95.
5. Baker, T. B., & Tiffany, S. T. (1985). Morphine tolerance as habituation. Psychological review, 92(1), 78.
6. Schuckit, M. A. (1984). Subjective responses to alcohol in sons of alcoholics and control subjects. Archives of General Psychiatry, 41(9), 879-884.
7. Schuckit, M. A. (1985). The clinical implications of primary diagnostic groups among alcoholics. Archives of General Psychiatry, 42(11), 1043-1049.
8. Dafters, R., & Anderson, G. (1982). Conditioned tolerance to the tachycardia effect of ethanol in humans. Psychopharmacology, 78(4), 365-367.
9. Remington, B., Roberts, P., & Steven, G. (1997). The effect of drink familiarity on tolerance to alcohol. Addictive behaviors, 22(1), 45-53.
10. Steele, C. M., & Josephs, R. A. (1990). Alcohol myopia. Its prized and dangerous effects. The American psychologist, 8, 921–933. [9] 9.
11. McCusker, C. G., & Brown, K. (1990). Alcohol-predictive cues enhance tolerance to and precipitate “craving” for alcohol in social drinkers. Journal of Studies on Alcohol, 51(6), 494–499. https://doi.org/10.15288/jsa.1990.51.494
12. Moore, S. C., Wood, A. M., Moore, L., Shepherd, J., Murphy, S., & Brown, G. D. A. (2016). A rank based social norms model of how people judge their levels of drunkenness whilst intoxicated. BMC Public Health, 16(1), 798. https://doi.org/10.1186/s12889-016-3469-z