Most people think that the top hat is taller than it is wide.

In fact, the two distances are exactly the same, and the illusion is caused by people perceiving horizontal lines as being shorter than vertical ones.

The same illusion makes people underestimate the width of short wide glasses, and so they tend to pour more liquid into the glass.

In fact, research from Cornell University shows that people pour 30 percent more liquid into short wide glasses than tall thin ones, and even experienced bartenders pour 20 percent more.

So, if you want to cut down on your drinking the easy way, go for tall thin glasses.