A rank based social norms model of how people judge their levels of drunkenness whilst intoxicated

Excessive alcohol consumption places drinkers’ health at risk both in the long term
and during the drinking episode 1]. In the drinking episode intoxication can lead to risk taking behaviours such as
unsafe sex, driving a motor vehicle while intoxicated, criminal or social misdemeanors
of varying levels of seriousness, and continuation of drinking until ataxia, coma
and even death occur 2], 3]. Mis-estimations of the degree of personal intoxication may contribute to such behaviours,
leading a person to believe that they are able to undertake a task safely when they
are not, or to believe that they can continue drinking without becoming dangerously
intoxicated. Understanding how people judge their drunkenness whilst intoxicated,
how their current state of intoxication impacts on their health, and how such estimates
can be systematically biased, is an important first step towards designing environments
and honing interventions to reduce excessive drinking and drunken mis-behaviour. However,
whilst much research has focused on how people evaluate the heaviness of their drinking
(e.g., 4]–7]), this research is normally conducted with participants whilst they are sober, and
little is known about how people evaluate their drunkenness whilst actually under
the influence of alcohol and in a drinking environment. The importance of this becomes
greater where there are concentrations of drinkers, a phenomenon which has increased
in UK cities that have been focal points for concentrated development of the night
time environment, leading to a high density of licensed premises.

Whilst intoxicated, people might be assumed to judge their levels of drunkenness based
solely on how much they have actually drunk. This intuitive “actual intoxication”
approach is perhaps a partial motivation for calls to increase the availability of
information on the amount of alcohol consumed, for example through mandatory labeling
of bottles with alcohol units 8].

We propose in contrast a rank based social norms model, which we test in a sample
of intoxicated individuals through modeling the relationship between people’s objective
drunkenness (based on breath alcohol concentration, BrAC, measured using an alcometer)
and their ratings of their drunkenness, as well as the relationship between their
BrAC and the attitudes they held at that moment about the health consequences of their
drinking. Specifically we hypothesize that when drinking alcohol amongst others people’s
perception of their own level of drunkenness is influenced by the perception of their
level of inebriation relative to others in their immediate vicinity. Our focus is
on social drinking and we make no reference to alcohol consumption that occurs in
isolation. The “actual intoxication” approach neglects existing social norms research
which indicates that – at least whilst individuals are sober – people are highly influenced
by their perceptions of how their levels of drinking compare to those of others within
their reference groups (e.g., 4]–7]). Whilst this conclusion has been established for sober individuals, the same may
not hold for real world settings (i.e., for intoxicated individuals in drinking environments).

First, it is not clear whether drinkers compare their levels of intoxication to the
actual levels of intoxication of those in the same drinking environment, or to their
incorrect beliefs about the levels of intoxication of others. Generally, social norms
research has shown that people have an inaccurate impression of how much others drink
– possibly being motivated by a desire to self-enhance through seeing themselves as
relative lower drinkers – and that it is this inaccurate impression that affects judgements
of the heaviness of actual drinking 4], 7]. However such research, conducted with sober participants in non-drinking environments
requires participants to rely on memory to make comparisons, and this involvement
of memory may lead to biased judgements about personal drinking 9]. In contrast, people can actually observe the intoxication levels of others whilst
in drinking environments 10], providing opportunities for people to be more influenced by the actual rather than
remembered states of others. The physical presence of others may reduce the biasing
effect of memory.

Second, it is also not clear whether: (a) comparisons to others would bias the basic
relationship between objective and subjective drunkenness (such that subjective drunkenness
would be predicted by both objective drunkenness and social comparisons), or (b) the
relationship between objective and subjective drunkenness is wholly based on comparisons
to others (such that when statistically controlling for social comparisons there would
no longer be a relationship between objective and subjective drunkenness).

Third, the cognitive mechanisms through which people compare their level of drinking
to that of others are not known. In making specific predictions for this study, we
were guided by independent research from psychophysics which focuses on how people
judge the magnitude of stimuli (see 11]). Such research is directly relevant as it concerns how people make subjective judgements
(here, drunkenness) based on objective magnitudes (here, objective intoxication).
Historically, such research has followed a path of initially assuming that people
are influenced by the actual magnitude of the stimuli (here, actual intoxication,
see 12]), subsequently assuming people are influenced by how a stimulus differs from some
measure of central tendency (here, for example, how one’s intoxication differs from
the average intoxication within the environment, 13]), and finally showing that people are only sensitive to how a stimuli ranks within
the environment (here, how one’s drinking ranks within the immediate environment,
see 11]). The rank hypothesis has been supported in a variety of other psychophysiological
14]–16] and social 17]–21] domains. Such a perspective raises the possibility that individuals in drinking environments
may base the estimates of the heaviness of their drinking wholly on how their level
of intoxication ranks relative to that of others (rather than rank based comparisons
providing an additive bias). Showing that common mechanisms apply in different areas
furthers the development of a more unified and integrated psychology 22] where the same cognitive mechanisms are shown to operate across multiple domains.

Fourth, if people do compare themselves to others, it is not clear whether their judgements
of their own intoxication would be equally, more, or less influenced by people who
drink more than they do relative to those who drink less. The alcohol and social norms
literature suggests that sober people have a tendency to over-estimate how much others
drink, this effect being consistent with a self-enhancement bias motivated by a desire
to see one’s consumption as relatively lower (e.g., 4], 7]). This might suggest that people would be more influenced by those who drink more
than they do themselves. However, it is again not clear that findings based on sober
individuals in classroom or home settings would generalize straightforwardly to intoxicated
individuals in real world environments. In such real world settings more sober people
may be more salient, leading to a greater relative comparison to those who have drunk
less. It is also not clear which comparisons a self-enhancement bias may predispose;
when sober people focus on general alcohol consumption it may seem preferable to drink
less, whereas whilst in a “party” mood and intoxicated in a drinking environment it
may seem preferable to drink relatively more. Thus the very self-enhancement biases
that predispose comparisons to heavier drinking people in sober environments may predispose
comparisons to lower level drinkers in real world ones.

In this study we examine for the first time how people judge their drunkenness and
the health consequences of their drinking whilst they are intoxicated in social drinking
environments. The focus on health was motivated by recent calls for more social norms
research to focus on perceptions of the health consequences of personal levels of
drinking in addition to simply perceptions of the heaviness of drinking 9], 23]. Based on previous social norms research we hypothesize that such judgements will
be influenced by how the individual compares themselves to others. As such others
are salient in this environment we further hypothesize that people will be influenced
by how the individual’s intoxication ranks amongst the actual levels of intoxication
of others in the environment. Finally, based on independent research from cognitive
science 11], 12], we hypothesize that judgements will be wholly based on how the individual’s intoxication
compares to others in the environment, and that these comparisons will be rank based,
arising from the same cognitive mechanisms used to judge psychophysical stimuli. We
have developed no specific hypothesis as to whether people will be more influenced
by those who are more or less intoxicated and leave this test as exploratory.