The Psychology behind ‘Related Products’

30th March 2022

4 minute read

“Related Products” are the lists of products we tag onto the bottom of a product on a website to show potential customers what other things they could buy. There’s something interesting in the psychology of how these products are shown which can, if done incorrectly, reduce the conversion rate of the page. I’ll explain how this works and the research behind it, but first let’s be clear about what this section is.On sales pages for products you often find a few things:

  • Related Products – a product which is related to the one you’re currently looking at
  • Cross-sells – a product which is used in conjunction with the one you’re looking at – i.e. batteries; a lens for a camera; pencils with art supplies.
  • Bundle sells – a few products bundled together into one price, usually at a discount.

These are three different things not to be confused, as the psychology behind each of them is different, as is where they should be used on the page and what should be included in the sections. They’re sometimes lumped together as one, or named differently, but if you understand what each are trying to do, where and how they should be used, you’ll be able to use all three to their best advantage when selling on your site. Here we’re just talking about “Related Products”, and these are generally shown at the bottom of single product pages. The ‘related’ part here is really important – and this is where the interesting part comes – if you show someone a ‘related product’ that is in fact unrelated to what they’re currently buying, customers are then less likely to buy the original product they’re looking at. We already know that when a customer is thinking about buying a product, if they are asked to think about what else they could spend that money on, their desire to then buy the initial product is reduced. (By the way, this is a handy hint if you’re personally trying to save money; stop and spend a few moments thinking about what other things you could spend that cash on instead). But what’s interesting is that this effect changes if the alternatives are serving the same goal as the initial choice or a different goal entirely

Researchers tested the following pages:

They then measured the likelihood of customers buying the initial Wireless speaker. In both cases the desire to buy the initial product was diluted, but in the second case, where the alternatives fulfilled a different internal desire, the dilution was far greater. 

The product they want to buy is called their ‘focal goal’ – the thing they’re focusing on buying. If we show the customer competing, dissimilar products then we’re reducing the importance of their ‘focal goal’, and making them less likely to buy the initial product. You’ll notice on Amazon that the first choice of alternative products are always ones which fulfil the same goal as the one you’re looking at – there’s a reason for this. Whereas if the other products also support that focal goal then they support the purchase more. This can even be an issue if the product is similar but its use is different. For example, if you’re selling blenders for creating healthy smoothies and then present them an option of a blender which is marketing at creating cocktails – in other words, a different focal goal – the intention to purchase the initial product is diluted. 

You can take advantage of this too. Let’s say I’m looking to buy pasta – then my focal goal is to cook something with pasta. So now ‘Related Items’ can be sauce, or cheese, or something that complements the focal goal. What it wouldn’t be is a pasta-maker or a bottle of wine, as these would possibly dilute the goal.

Whether this becomes a problem or not depends on the type of site you’re running and the products – if you drive a customer to your site with the promise of a particular type of product, one which you specialise in, then their focal goal is established before they even get to you. To change that focus once they’re on the site could result in lost sales, so this would be something to be careful of and to test and measure. Initially, I would suggest making sure that ‘Related products’ are just that; specific options within the theme of the product page they sit on.

From there you could introduce additional items, and measure both the conversion rate of the page, and the conversion rate of visitors on other products (and more importantly, the value of the sale made and the profit from it) and tweak from there.

Source:S, F.E., Jennifer, S.., & Ravi, D.. (2018). Apples, Oranges, and Erasers: The Effect of Considering Similar versus Dissimilar Alternatives on Purchase Decisions. Journal of Consumer Research, 45(4),

Written by Rob Dobson

Rob Dobson has been working in digital and building websites for 20 years. From designing and developing the world’s first internet bank in 1999 (, he founded Northern Comfort in 2010.

See how we can help you.