You have two glasses of wine. You’re told one glass is from a $40 bottle and the other from a $10 bottle. Which would you think tastes better?

If you think the glass from the $40 bottle, you’re likely right. Research suggests that in a taste test people will say the pricier bottle tastes better. This remains true even when both glasses of wine are poured from the exact same bottle, and you’re lied to about the price difference.

Why is this the case? It’s because your brain is wired to play tricks on you.

Researchers at the University of Bonn in Germany and INSEAD, a graduate business school in Europe, found two areas of the brain — the medial prefrontal cortex and the ventral striatum [STRI-AY-TUM] — are responsible for how we perceive the correlation between price and taste.

The researchers asked people to sample three glasses of wine while lying in an MRI scanner. People were told the glasses of wine were poured from bottles that cost either 3, 6 or 18 euros, which converts to about $4, $7 and $21, but they all actually cost the same.

Most study participants said the wine they were told cost more tasted better. MRI scans showed this happened because the areas of the brain involved in evaluating expectation and reward seeking lit up when people tasted what they thought was the most expensive glass. In layman’s terms, our brains expect that an expensive item will yield a higher reward, such as a better-tasting glass of wine.

The best way to evaluate taste is to sample wine, or any food item, before you know its price. This way, you’ll know if you like it because of its taste, not because its price tag is messing with your brain.