IT is just five days until Black Friday when bargain hunters will be flocking to the shops to bag a deal.

Last year, Intu Derby saw a 30% increase in visitors on the day compared with a normal Friday and UK shoppers spent £1 million every three minutes on the day itself, resulting in total sales of more than £800 million.

But the knockdown prices also resulted in appalling scenes of shoppers fighting over widescreen televisions.

So what is it that drives us to find the best bargains? James Hallam, academic lead for psychology at the University of Derby Online Learning, answers some questions about the psychology behind bagging a bargain.

Why do people like bargains?

The way price reductions are presented online and in store tap into some primal psychological impulse that everyone has within them. Psychologically, when we see a price reduction it appeals to us because it appears that the retailer is not in complete control of the final price of the product. This makes us feel like we are in control of what we pay and makes us feel powerful.

The excitement of bargains interfere with our ability to clearly judge what we should and should not be purchasing. Internet sites and shops take advantage of this mentality by using tactics to portray certain products in a way that starts to excite us. For example, shops will always advertise a bargain by focusing on how much you will be saving were you to purchase the product. This shifts our focus away from what we actually spending to how much we will be saving on our purchase. This makes a bargain even more exciting and as such an emotional investment.

Why does Black Friday create so much hysteria?

The allure of a bargain speaks to human nature, and the limited-time-only nature of Black Friday triggers an innate fear of scarcity that drives people to buy, buy, buy. Many people view Black Friday as an unmissable opportunity to purchase products and items at the lowest price possible. This inspires a fear of 'missing out' that we don't consciously understand or notice which in turn enhances the power of our emotional reaction. Our anticipation builds up so we may not actually know why we're jumping to purchase that 70% off a pair of shoes that we didn't actually want before we saw the reduction.

This fear of 'missing out' is heightened further by the knowledge that we are directly competing with other people to purchase these reduced items. This causes mass hysteria as we battle with strangers to get hold of the last reduced television left on the shelf. The last thing we want is for someone else to grab an unbelievable bargain that we have missed out on.

The Black Friday event in 2014 often led shoppers to engage in fist fights and other misbehaviour in their desperation to snatch up the last television, computer or pair of shoes. This irrational behaviour is an example of the sort of emotional feelings that are triggered in humans when we believe we have missed out on a bargain. Were we to walk into the same store on any other day of the year and see the same person pick up the last one of a particular product that is on offer, we would not wrestle this person to the ground in order to take the item for ourselves. The misbehaviour seen in people in the past has caused some retailers to announce they will not be taking part in the Black Friday event this year in order to avoid similar occurrences.

Another key factor is the timing of such a large sales event falling only 28 days before Christmas Day. This causes a further emotional reaction meaning shoppers' cognitive levels are not functioning at top form, resulting in impaired decision-making and heightened negative mood states, thus facilitating over spending and misbehaviour.

Can people get addicted to bargain hunting and why?

Academic research carried out in this area highlights that people are not necessarily motivated by financial gain when bargain hunting. Instead, it seemed that acquiring a bargain was primarily considered a matter of luck and power over the retailer. Research also claims that bargain hunting is genetically programmed in all humans, although it's activated much more in some than others. Purchasing something at a reduced price triggers a release of dopamine, the feel-good neurotransmitter. Dopamine is such a powerful chemical that it causes physiological reactions that mean we are prone to splurge, especially on bargains. A release of Dopamine can be triggered in some by simply seeing the word 'sale' or 'bargain'.

These feelings give us a sense of 'winning' which becomes very addictive. The five signs to of being addicted to bargain hunting to watch out for are:

You hit the sales when you feel angry or fed up

You spend more than you can afford

You often forget what you've purchased and find things in your wardrobe that you've never used

You see sales as an opportunity you can't pass up

You spend most of your time searching for reduced price items

What tactics do retailers use to get people to spend money, particularly on Black Friday?

Retailers pull out all the stops on Black Friday with stores opening at the stroke of midnight (online and offline) creating a sense of urgency in shoppers getting people in the mood to spend. One of the first things you will see on any product is how much money you will save giving you a feeling of getting a high. You feel good about saving money, and that makes you more likely to buy, even if you never intended to make that purchase. Retailers will often manipulate this figure by displaying a higher than usual original price and an amazing not-to-be missed sale price.

We have to remember that retailers will always try to trick us into thinking we're getting something for less money. As soon as we enter a shop (online or offline) we are being bombarded with numerous psychological tactics in an attempt to get us to buy more products (such as selling products that have a price ending in 99p).

What are the pitfalls of Black Friday shopping on our emotional health?

The main pitfall of Black Friday is that the sense of urgency created by retailers causes many people to spend more money than they can actually afford in order to not miss out on a bargain. People are much more likely to reach for their credit card or dip into their savings in order to buy that item with an 80% reduced price tag. It is only after the big event that on reflection we start to feel stressed by the amount of extra money we have spent.

Consider these tips to keep you on track and away from overspending on this Black Friday:

Make a list. Approach the day with a clear idea as to what you want to purchase and stick to your list.

Don't fall victim. Retailers will always try to manipulate the situation in order to make money. Keep this in mind and don't purchase anything that you don't need.

Enjoy the day. Black Friday provides a unique opportunity to purchase reduced items that you've had your eye on for a while. You have to enjoy the fact that you are buying something you have wanted for a reduced price.