Supermarket music picks your wine for you

In 1997, British researchers placed a speaker next to a supermarket's wine shelf. On days with French music, French bottles outsold German ones five to one. On days with German tunes, German wine won. When shoppers were asked, almost none admitted — or even realised — that the music had played a part. The study ended up in the journal Nature.

It's no isolated case. Back in 1982, another classic experiment showed that slow music makes customers walk more slowly down the aisles — and the tills notice: more time inside, more items in the trolley.

None of this is accidental. A supermarket's soundtrack is a sales tool as carefully engineered as the placement of the products.

So if you ever leave the supermarket with a bottle you hadn't planned on, check what was playing.