Shopping Trolleys. There is more going on than you might realise

Visit any large supermarket and you’ll see most shoppers using a trolley (or shopping cart if you are in the USA). They are so ubiquitous that you probably don’t give them a second thought; unless you are unlucky enough to use one with a dodgy wheel but the design of these mundane items has a big impact on what we buy in store.

Shopping trolley and basket

The shopping trolley: the ‘greatest salesman’ around 

First introduced in 1937 by Sylvan Goldman, an Oklahoma supermarket owner. He noticed that when shopping, as peoples’ baskets started to become too heavy to carry, they stopped buying -even though they had not bought everything on their list. Working with a local handyman, they took inspiration from the design of a folding chair. They raised the height of the seat and placed a basket there; this gave them space for another basket below. Finally, they placed the contraption on wheels.   

But when it was first launched, the trolley wasn’t a success. Women complained that it felt like they were pushing a pram around the store, whereas men claimed that it was emasculating, implying they were not strong enough to carry a basket. However, Goldman wasn’t perturbed. Rather than try and convince shoppers with a rational argument, he adopted a more subtle tactic. He paid his employees to walk around the store using the trolley. What today we would call a ‘social norm’ campaign and this was enough to convince shoppers to try them – leading to a dramatic increase in sales in his store. So much so that the trolley was referred to as the “greatest salesman”.  

Over the years the design has changed slightly. Rather than having two baskets, it changed to just one large basket and in recent years, the size of the trolley has got bigger. This is driven by experiments as research has shown that as the trolley doubles in size, shoppers typically buy 40% more. This occurs because we use the size of the trolley as a cue as to how much we should buy. We presume the size of the trolley represent the amount that we should buy on a typical shop. 

The trolley of the future…

Yet researchers are also looking at more innovative ways to work out how a shopping trolley can be redesigned to influence shoppers’ purchasing habits. In the future one change you may start to notice is the way that you push the trolley. Unfortunately, supermarkets are not going to include an electric motor, you're still going to have to push your trolley, but they're looking at changing the handle design. Today, most trollies have a long horizontal handle. As you push it, this works your triceps muscles in your arm. This may not sound very important, but previous research has shown that triceps activation is associated with rejecting things. For example, when we push something away that we do not like, our triceps are activated. However, if we are pulling something towards our body, our biceps are activated. This meant the researchers tried to design a new trolley that activated our biceps as we pushed it and they achieved this by designing a new trolley with parallel handles (similar to those found on a wheelbarrow).  



The results. Shoppers using the traditional trollies spent on average €22, but when using the new trollies, they spent on average €29 – a 25% difference in spending. And unlike a lot of experiments, this was not looking at hypothetical purchases made in a laboratory context. The researchers created these new trolleys and introduced them into a major supermarket. Participants were unaware that they were taking part in an experiment, as they were just doing their normal shopping.  


At first glance, this finding appears to be too good to be true. On hearing this finding, I first assumed that the change in behaviour must be explained by the novelty of the new trolleys. After all, we have used the same design of trolleys for all our lives. Perhaps this quirky new design increased involvement?  The researchers also had the same thought. They conducted a follow up experiment testing the effect of horizontal, vertical, and parallel handles. Both the vertical and parallel handles were novel, but only the parallel handles increased sales – suggesting that their initial hypothesis (the activation of the flexor muscles) was correct. 

But this isn’t the only change that you might notice. Some stores are experimenting with dividing the shopping cart into different sections (e.g. meat, fruit & veg etc.). The theory is, the larger the section, the more of these items’ shoppers are likely to buy – again we use the size of the section as a cue to what we are meant to buy and this appears to work. In one experiment where the shopping trolley was divided into ‘Meats & Treats’ and ‘Fruit & Veggies’, they found the size of the section directly influenced how much people spent. In the control condition (with no divide), shoppers spent on average $10.36 on fruit. When the fruit section made up 35% of the trolley, they spent $11.85 on fruit, and when the fruit and veggies section comprised 50% of the trolley, shoppers spent $13.40 on fruit and vegetables. Although the researchers were using this tactic to encourage shoppers to purchase more healthy food items, the same approach could be used to sell more high-margin items – it just depends on the stores motive.   

While adding dividers to a shopping trolley is a low-tech solution, in the future we may see some high-tech developments. If products contain RFID chips, it means that as soon as we place an item in the trolley, we can get instant feedback, for example a running total of how much we’ve spent. Although, just because we can do something, it doesn’t necessarily mean we should.  

Providing real time feedback caused budget conscious shoppers to spend 34% more. Regardless of whether they had feedback or not, budget conscious shoppers stayed underbudget. The difference was that without feedback they spent 79.2% of their budget, but with feedback they spent 94.6% of their intend budget - resulting in a less stressful shopping experience. However, for shoppers who weren’t cost conscious providing real time feedback caused them to spend 24.9% less. Providing real time feedback, made the roll of price far more salient. However, if a store has done a good job at segmenting the market and understands who their target market is, they should be able to understand if this is an intervention they want to implement or not. 

Closing thoughts  

For the last fifty years, supermarkets have taken a scientific approach to the design of the retail environment. Every detail ranging from the music played, the width of the aisles to the height of the ceiling carefully considered to encourage customers to spend more. Yet for most of this time, shopping trolleys have been overlooked as a mundane functional aspect  - but maybe next time you’re in a store, take a closer look at a trolley. They might look rather different in a few years’ time. 



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Estes, Z., & Streicher, M. C. (2021). Getting a Handle on Sales: Shopping Carts Affect Purchasing by Activating Arm Muscles. Journal of Marketing, 00222429211061367

Lindstrom, M. (2012). Brandwashed: Tricks companies use to manipulate our minds and persuade us to buy. Kogan Page Publishers. London, U.K.

Van Ittersum, K., Wansink, B., Pennings, J. M., & Sheehan, D. (2013). Smart shopping carts: How real-time feedback influences spending. Journal of Marketing77(6), 21-36.

Wansink, B., Soman, D., & Herbst, K. C. (2017). Larger partitions lead to larger sales: Divided grocery carts alter purchase norms and increase sales. Journal of Business Research75, 202-209.

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