There's no joy like the moment when a sales assistant hands over a crisp carrier bag containing a brand new purchase.

We've always known shopping brings us a kind of satisfaction that's unrivaled, but according to science, retail therapy is a real thing.

A 2007 study, recently resurfaced by The Atlantic shows that the brain finds pleasure in the pursuit of new things, such as finding an item of clothing you really like in a store.

Using fMRI technology (a technique for measuring and mapping brain activity), researchers from Stanford University, Massachusetts Institute of Technology and Carnegie Mellon University observed the brains of test subjects as they were shopping for clothes. 

When a subject saw a desirable object for sale, the pleasure centre (nucleus ambens) in the brain lit up. As the person developed a desire for the item, the fMRI detected more activity.

The report concluded that act of wanting and pursuing something when shopping can stimulate happiness.

But what's even more fascinating is how the brain reacts positively to finding a bargain.

When the subject was shown the price of an affordable item in the study, the insula (the part of the brain which processes pain) initially reacted to the cost. To put it into perspective, an expensive item will cause the insula to be most active part of your brain. It's you body's way of telling you to not buy it.

But in the study, the item with a lower cost caused the medial prefrontal cortex (the rational part of the brain) to show the most activity. Researchers described it as a "hedonic competition" as it tried to decide between "between the immediate pleasure of acquisition and an equally immediate pain of paying".

"It seemed to be responsive not necessarily to price alone, or how much I like it, but that comparison of the two: how much I like it compared to what you charge me for it," says Scott Rick, one of the study’s authors

In other words, the brain reacts positively not just to something you like in a shop, but specifically to the prospect of a bargain.

Another study from the University of Michigan last year found that the act of shopping made subjects feel three times less sad and up to 40 times more in control of their life than those who only browsed shelves.

“Retail therapy – shopping that is motivated by distress – is often said to be ineffective, wasteful and a dark side of consumer behaviour, but we propose that retail therapy has been viewed too negatively, and that shopping may be an effective way to minimise sadness,” researchers said at the time.

It seems that the combination of finding something you like and a bargain, really can make you happier. Pay day never looked so bright.