This article takes a look at several reasons for the increasing size of grocery carts. There are a few theories that proved interesting. The first theory discussed comes from the viewpoint of behavioral economics. The theory is that by increasing the size of the grocery carts, stores are able to establish a consumption norm consistent with the size of the cart. In other words, grocery stores are attempting to influence consumer consumption habits. Another explanation is that as more women enter the labor market, fewer trips are being made to the grocery store. This has the effect of increasing the number of items purchased in a single trip. A third explanation is that they were always too small.
I tend to believe that the carts are larger to accommodate bulk purchase items. As the article points out, superstores have a few advantages when it comes to bulk items. They have lower costs because of favorable economies of scale. They also have monopsony power when brokering deals with suppliers. Stores like Costco and Sam’s Club have discovered that they are able to target price-sensitive customers by offering items in bulk. Wal-Mart and other superstores have also found that bulk items are an effective means of implementing price discrimination. By offering bulk items, stores are able to offer a lower price per unit in exchange for greater sales volume. This allows them to charge two different prices for the same item. Ultimately, by increasing cart sizes to accommodate bulk items, stores are more efficiently meeting their customers' needs.