Supermarkets influence their customers through many manipulations of the layout and contents of the shop, causing people who only wanted to buy one or two select items to buy many, many more.
The entry of most supermarkets contains flowers and then fresh fruit and vegetables. They are displayed here on purpose because they are colourful and attractive, consequently putting you in a good mood and making you more willing to spend. The fresh food areas are also where customers tend to spend the most time. By placing these at the beginning of the supermarket they encourage the length of time spent at the fresh food areas to be replicated across the different areas of the shop and so alter the speed at which customers go around the shop. The use of slow music has also been shown to make people take their time and spend more money (Milliman, 1982). Increasing the amount of time in the rest of the shop also increases the amount of money as a result
A second point of interest is that the size of shopping trolleys has increased over recent years. This results in people buying more, in order to fill the trolley. This can be further facilitated by supermarkets offering miniature trolley’s disguised as toys to keep children occupied. These in fact result in the parent feeling obligated to put items in the trolley and buy them too; further increasing the amount spent. The effect of trolley size could be explained by anchoring, in which this cognitive bias causes an initial piece of information (trolley size) to influence further decisions (the amount to purchase). If you enter a shop with a basket (a smaller anchor), rather than a trolley, you spend considerably less. The anchoring effect was demonstrated by Russo and Shoemaker (1989). They required participants to think of the last three digits of their phone number, to add 400 to it and to think of it as a date. After this they were asked to consider whether Attila the Hun was defeated in Europe before or after that date, and in what year they guessed Attila the Hun was actually defeated. They found initial, irrelevant information – the last three digits of participants’ phone numbers influenced their subsequent guesses of dates.
Milliman, R. E. (1982). Using Background Music to Affect the Behaviour of Supermarket Shoppers, Journal of Marketing, 46, 86-91.
Russo, J. E., & Shoemaker, P. J. H. (1989). Decision traps. New York: Simon and Schuster.