Image copyright Getty Images

People are more savvy than ever before about the ways shops get them to spend their money, but the retailers are always coming up with new tactics.

Why are sweets and chocolate always by the till in supermarkets? Why do they put the everyday essentials like bread and milk at the back of shop so you have to walk through as many aisles as possible to reach them?

Why is the perfume and jewellery section always at the front of a department store?

Why do some shops have low lighting? Why in Ikea do you have to do a loop of the whole shop rather than being able to get straight to the bit you actually want?

Take the Lab UK Big Money Test Covers your money motivation, knowledge and how you respond emotionally to spending

Get personalised feedback from money saving expert Martin Lewis Take the Big Money Test Find out what the results show

Many of us will have realised the tricks that retailers use to get us impulse buying, but it doesn't stop us.

"We're all children when it comes to shopping," says money saving expert Martin Lewis.

"We have to remember that shops will try to trick us into thinking we're getting something for less money when we're not. It's their job to make money and it's your job to stop them making money."

The findings of the BBC Lab UK Big Money Test reveal the impact spur-of-the-moment buys have on our finances, having a greater impact on our ability to make ends meet than financial knowledge, education, income and social class combined.

Part of the problem is retailers are always coming up with new ways to get us to spend. Here are some of them.

Getting messy

Image copyright Thinkstock

Instead of constantly tidying the shop floor, some shop assistants are strategically messing things up. It's a tactic to make items appear popular, as if lots of people have been looking at them and they are a must-have.

It works well on younger shoppers. Under-21s are the most likely to make an impulse purchase, according to the Big Money Test.

What the Big Money Test tells us If money makes you feel powerful you are more likely to encounter money problems

If money makes you feel secure you are less likely to experience money problems

A third of people who took the test said they thought about money all the time

Half said they resent the full price for goods in shops

Women are much more generous with their money than men

Men are more likely than women to associate money with freedom Explore the results of the Big Money Test

Young people are also hugely influenced by what others are buying, says Philip Graves, consumer behaviour expert and author of Consumer.ology.

"They are seeking a sense of their own identity distinct from their parents. They are looking to affiliate with others they think are like them."

The problem for teenagers has a biological as well as social explanation.

"The part of the brain that's responsible for impulse control doesn't develop fully until your early 20s," says one of the Big Money Test's designers, Mark Fenton-O'Creevy, a professor of organisational behaviour with the Open University.

Brand blurring

A consequence of the country's current financial woes is that shoppers want to feel they are getting value for money, even if they haven't personally experienced any change in their income or lifestyle, says Graves.

The expert's tips to beat the shops You need what I call a piece of 2D technology - a shopping list, before you go shopping. It should be linked to your meal planner when food shopping. I've got two money mantras, one for skint people - do I need it, can I afford it and can I get it cheaper elsewhere? And one for people who have more money - will I use it, is it worth it and can I get it cheaper elsewhere? Never buy on the day you see something you like, sleep on it. You can lust over goods but that wipes away any clear logic. It's like making a decision when you're drunk. Martin Lewis Find out how much of an impulse buyer you are Watch Martin Lewis's money saving tips

"The constant media message that money is tight has created an unconscious wariness among consumers."

People want value but also want to feel good about what they buy, say consumer psychologists.

"When money is tight it's not just about buying the cheapest thing out there," says Joseph Staton, director of GfK Consumer Trends.

"It's about feeling like you are making the right decision."

It has caused problems for supermarkets' value brands. While they save the pennies there can also be a stigma attached to them.

The shops are tackling this by "brand blurring" and making the difference between cheap and mid-range goods less distinct.

Ranges have been rebranded so they don't scream cheap, in some cases the word "value" has disappeared altogether.

They are being marketed as a "wise" choice - not just a cheap one. Blurring the boundaries attracts a new, much wider range of shoppers.

"The value brand is being elevated so people feel better about buying it," says Graves. "Retail is a constant manipulation game."

Location-specific offers

Image copyright Getty Images

"Big data" is creating a big buzz at the moment. It's the gathering and analysis of data on a huge scale.

Why do people impulse buy? People who are more sensitive to pleasure and pain, who feel highs and lows more intensely, are more inclined to be impulse buyers. Women are more likely than men to be impulse buyers. Retailers will use their knowledge of our psychology to draw us into offers like six month interest free credit on purchases. Retailers know that people are overly optimistic about their ability to pay it all off in the time scale. Pay day loan companies also rely on impulse and optimism. Prof Mark Fenton-O'Creevy How does money make you feel? Emotional finance: Mark's blog

"That information comes from any number of places - your financial transactions, digital photos, social media posts, mobile phone GPS signals and Google searches to name just a few.

Companies already use such data to personalise offers for individual customers, but now they are planning the use of GPS location data to target you when you are actually walking past one of their shops.

"It's all about enhancing location-specific data to get people to impulse buy," says Staton.

"It plugs into offering high levels of customer service and tailoring offers to what the customer wants. It's being done by high-end shops but is filtering down to the High Street."

Eye tracking

Image copyright Thinkstock

Brands are constantly fighting to get your attention and keep it. One new approach is "retail theatre".

It's about surprising the shopper and giving them an experience, says Paula Dowie, managing partner at retail design agency Ignite Design.

Can you work out a good deal? 78% of Britons have numeracy below Maths GCSE Grades A* to C standard

They may not be able to compare products and services for the best buy or work out a household budget

Of those, 25% of people have numeracy skills equivalent to the average 9 to 11 year old and may not be able to understand price labels on pre-packaged food Source: Skills for Life survey How to improve your maths Get help with other life skills

"Good retail design is about disrupting the consumer's thinking, getting them to notice you and making them linger for longer," she says.

In the crowded perfume market that's hard. People usually stop, spray and move on in a matter of seconds. Now luxury brands like Gucci are using the eye-tracking technology to keep their attention.

Digital screens behind display stands are activated when a perfume bottle is picked up, flashing images to seduce you. Eye-tracking systems are fixed into screens to gather data so the images can be personalised. And it's all done a matter of seconds.

"Certain software programs can gather huge amounts of data on you almost instantly," says Dowie. "Age, gender, what you're looking at - that sort of thing. If you're a young women or a middle-aged man, images are then flashed up that will appeal to you."

As the technology becomes more widely available it will filter down to High Street shops, she adds.

It's about entertainment and making your shop one that people want to come to. Brands like Apple and Top Shop are "genius" at doing this, says Staton. During London Fashion Week last month Top Shop screened its own fashion shows live in its flagship store in London's Oxford Street.

"It's about adult play, making a space different to other shops and offering things like art and music as part of the shopping experience," says Staton.

You can follow the Magazine on Twitter and on Facebook