Much of the global burden of disease is attributable to behaviour, including consumption of alcohol and sugar-sweetened beverages. Developing ways to reduce intake of these drinks could thus improve population health. Glassware has the potential to moderate drinking, including how much is consumed. This thesis explores the impact of glass design on drinking behaviours in four pre- registered experiments.

Study 1 investigated the effect of glass shape on total drinking time. Drinking was 21.4% faster from outward-sloped tumblers than straight-sided ones (95%CI[0.2%,38.0%]). Drinking time did not differ between inward-sloped and straight-sided tumblers. Though drink midpoints were underestimated more from outward-sloped than straight-sided glasses (mean difference=-12.9ml, 95%CI[-6.6ml,- 19.2ml], midpoint-bias was not associated with drinking time (r(162)=0.01, p=.87).

Study 2 extended Study 1, comparing straight-sided vs outward-sloped tumblers, and exploring drinking trajectories. Total drinking times did not differ between glasses (0.3% difference, 95%CI[- 21.4,18.1], p=.98). Drinking trajectories were more decelerated from outward-sloped glasses. Midpoints were underestimated more from outward-sloped glasses (mean difference =-14.1ml, 95%CI[-9.5ml,-18.7ml], p<.0001), though midpoint-bias was not associated with drinking time (r(198)=-.09, p=.20).

Study 3 investigated the effect of glass shape on volume consumed in a bogus taste test. Participants consumed 72ml less from straight-sided flutes than outward-sloped coupes, 95%CI[-11.7ml,- 132.6ml], p =.022. Number of sips did not differ between glass shapes, but was positively associated with amount consumed, r(71)=.48, p<.0001. Midpoint-bias did not differ (mean difference -1.4ml, 95%CI[-5.8,3.0], p=.53), and was not associated with amount consumed, r(72)=-.03, p=.83.

Study 4 used electromyography (EMG) to measure ‘embouchures’ – the positioning of the lips – during sipping. When sipping from straight-sided flutes, participants used 8.9% more upper lip muscle activity (95%CI[3.3,14.8], p=.0017), and 20.0% more lower lip muscle (95%CI[14.7,25.6] p<.0001), than when sipping from outward-sloped martini coupes, suggesting more pursed lips during sipping from straight-sided glasses.

Using a combination of methods including objective measures of volume drunk and physiological measures, this thesis describes findings which have the potential to contribute to the development of novel, effective interventions which target glassware design to reduce consumption of health-harming drinks.