Alcohol consumption is associated with increased mortality and morbidity, with approximately 4% of the global burden of disease attributable to alcohol use 
. In recent years, there has been particular concern regarding patterns of alcohol consumption in adolescents and young adults across several countries. Rates of heavy episodic drinking (binge drinking) have increased in this group in the United Kingdom and elsewhere, in particular in young women 
, with corresponding increases in the risk of personal and societal harm. Furthermore, estimates of drinking behaviour that are based on standard units of alcohol may underestimate levels of consumption. Gill and Donaghy 
report that drinkers were more likely to self-pour single drink servings that were in the region of two units of alcohol, indicating that a “drink” is not necessarily equivalent to a “unit”. Individuals may also underestimate the alcohol content of beverages as ostensibly similar classes of beverage (e.g., beer) vary widely in alcohol content, and therefore drinkers may be less able to gauge their consumption during a drinking episode and may underestimate the amount of alcohol that they have consumed 
. There is a need to better understand the factors influencing alcohol consumption and binge drinking, in order to inform policy and enable the design of public health interventions.
Alcohol consumption is known to be sensitive to factors such as price, with price elasticities (i.e., the change in demand for a product in response to a change in price) in the United Kingdom estimated as −0.48 for beer consumed on premises, meaning that a price increase of 10% (e.g., through increased taxation) would result in a decrease in consumption of 4.8% 
, and therefore a corresponding decrease in alcohol-related harms. Similar price elasticities have been observed for other alcoholic beverages 
. Other restrictions on availability, such as increased drinking age, reduced hours and days when alcohol may be purchased, and reduced number, density and type of alcohol outlet, have also been shown to reduce consumption levels 
. Unfortunately, despite evidence for the effectiveness of these alcohol control measures and apparent public support for implementation targeted controls 
, most governments have been unwilling to adopt many or all of them 
There may be other potentially modifiable factors which may influence alcohol consumption and drinking rate. These might include marketing signals (i.e., branding), and vehicles for these signals such as the glasses from which beverages are consumed. Legislation to control or limit these signals may therefore influence drinking behaviour. A parallel can be drawn with the tobacco control literature, where plain packaging has been shown to increase visual attention towards health warnings compared with branded packaging in non-smokers and light smokers 
In particular, there has been an increase in branded drinking glasses in the United Kingdom in recent years, many of which include shape as a differentiating feature. These glasses include chalice glasses, curved beer flutes, tankard and novel curved beer glasses, and have been used by numerous alcohol brands including Stella Artois, Heineken, Guinness, Pilsner, Amstel, Smirnoff, Carlsberg, Carling and Jameson's whiskey. While alcohol advertising is still permitted in the United Kingdom, packaging and, by extension, drinking glasses provide another, currently unregulated, marketing channel.
As well as presenting overt branding information, these glasses may influence drinking rate by disguising the volume of beverage remaining. Anecdotally, this is particularly the case in curved glasses where the majority of the volume is contained in the upper portion of the glass. There is also empirical research to support an influence of object shape on volume perception 
. For example, there appears to be a bias to use information in the vertical plane when making judgements about the volume of an object, such that taller objects are judged as having a larger volume 
. Volume perception has also been investigated in relation to marketing and consumer behaviour. Perceptual characteristics such as the height of the container may be used as “visual heuristics” to make judgements about the volume of the container 
. Furthermore, Raghubir and Krishna 
suggest that in contrast, perceived consumption is inversely related to object height, suggesting that individuals will perceive that they have consumed less from a taller container compared to a shorter one. There is also evidence indicating that glass shape can influence pouring practices. Wansink and van Ittersum 
asked participants to pour a standard shot of alcohol, and found that both students and bar tenders tended to over-pour into a short wide glass compared to a slender glass of the same size. These findings indicate that object shape can influence not only the perceived volume of an object, but also behaviour towards the object when interacting with it.
To date there has been no research investigating the effect of glass shape on drinking behaviour. We therefore explored whether glass shape modifies the time taken to consume alcoholic and non-alcoholic beverages. We hypothesised that glass shapes where it is more difficult to accurately judge when half the beverage has been consumed would be associated with faster rates of drinking, compared with glass shapes where it is easier to make an accurate judgement.