Plastic Bags – Can 5p change the world?

plasticbag1From 5 October 2015, England will finally introduce a charge for plastic carrier bags.

All large supermarkets will legally be required to charge 5p per bag, as part of the UK Government’s environmental push to reduce the use of single-use plastic bags and encourage the use of re-usable bags or “bags for life”.

Similar laws have already been in place in Wales since 2011, Northern Ireland since 2013 and Scotland since 2014.

The success has been dramatic. A Welsh government review found 71% less plastic bags being used in Wales in 2015 compared to the same period in 2011, before the charge was introduced. While in Scotland, large supermarkets like ASDA and Morrisons reported similar reductions of 80% – 90% in the quantity of plastic bags used by consumers.

Aside from its objective success in changing our behaviour towards plastic carrier bags from a “throw-away” mind set to a more environmentally-conscious one, the initiative raises three interesting methods for how to influence human behaviour:

1. The Zero Price Effect

Why does such a small charge of 5p have such a big impact on our behaviour?

If the average shopper uses four plastic bags in their weekly grocery shop, this is only an extra 20p per week. Yet this is big enough to shift us from a life-long habit of using previously free single-use plastic bags, to remembering to bring a reusable plastic bag each time we visit the supermarket.

The answer may lie in the effect a “FREE” product has on our minds. Marketers have long exploited the powerful effect of “FREE” on us, for example by offering us “Buy One Get One FREE” deals to encourage us to buy more. Or altering their pricing strategy, for example if a retailer wants to increase sales of an add-on product worth £2, a pricing strategy of “£10 for the item plus a £2 add-on” is not advised. Instead, “£12 item plus FREE add-on” will be significantly more effective at getting sales.

The word “FREE” implies our purchase has no negative side, it only has an upside. It influences us on an emotional level. We are receiving something in return for nothing. In Behavioural Economics, this is known as the Zero Price Effect.

The case of plastic bags is the reverse Zero Price Effect. An item that was previously FREE is now only available at a charge. We can’t bear the thought of paying 5p for something we used to get for FREE, so we are prepared to change our behaviour. However this only works when a price of “zero” is involved. If tomorrow, the price of our regular pint of milk is increased from 45p to 50p, we may grumble at the minor extra cost, but we are unlikely to move en mass to switch to alternative brands or stop drinking milk altogether. Thus, psychologically the gap between 0p and 5p, is far greater than the gap between 45p and 50p, and we are thus significantly more motivated into changing our behaviour when “FREE” is involved.

2. Questioning forces us to think

A second mechanism contributing to the success of the 5p plastic bag charge is the new question we are asked at the checkout every time we do our grocery shopping: “How many bags would you like to use?”

Previously we never had to think twice about how many plastic bags to use, after all, they were free. The environmentally-conscious of us may have voluntarily considered using less plastic bags, but for the vast majority of us, we would previously use as much as we liked. Now we are faced with a choice.

A field study by Argentinian psychologist attempts to quantify this effect, and suggests that as well as the economic incentive of wanting to avoid the tax-like plastic bag charge, our behavioural change is also influenced by the mere fact of having to consider the option of using 0, 1 or 2+ bags at the checkout,

“After the introduction of the plastic bag charge, customers had to explicitly approve or request to obtain a bag and pay for it,” reports the study. In other words, we had to think before we act.

The thought of changing our behaviour would not have crossed our minds before, unless we were asked the question.

3. Visible doesn’t always mean significant

The UK Government’s intention by introducing this charge is to reduce the amount of waste going to landfill sites. It is staggering that in England alone, it is estimated that 7.6 billion single-use plastic bags were used in 2014. This is equivalent to an average of 140 bags per person per year.

However, reducing our plastic bag use doesn’t necessarily mean we are reducing our overall waste generated. In fact, it’s not even making a dent. Annual tonnage of household waste generated in England in 2013-14 was 22 million tonnes, while the Government expects that the new 5p charge will save approximately 61,000 tonnes per year of plastic bags being disposed of in England. That is under 0.3% of the total.

Surely there are bigger streams of household waste we should be tackling? Most definitely, yes. However human behaviour is not all about what is factually significant. The visibility of plastic bags in day-to-day life, from grocery stores, to our homes, to litter on the street, means there is immense psychological value in tackling them first.

By encouraging us to use plastic bags more wisely, it may positively influence our behaviour towards the use of other finite resources, and eventually shift us away from our throw-away culture of other items too. Maybe 5p really can change the world.

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