Limiting yourself to just one glass of wine isn’t always an easy task. And it turns out it may be even harder depending on the size of that glass. The Behavior and Health Research Unit at the University of Cambridge recently studied patrons at a local pub in hopes of finding out if changing the size of the wine glass has any effect on drinking behavior. (And no, we aren’t talking Betty White-sized glasses.) It turns out, decreasing the size of the glass has no noticeable effect, but increasing the glass size does. In the experiment, the same amount of wine was poured in varying glasses. Nonetheless, people felt there to be less wine in the larger glasses. That led them to drink faster and drink more–10% more. So it seems like the question isn’t: is the glass half full or half empty? But: how big is the glass?