Decision Theory is a diverse subject that attempts to research, analyze, and sometimes predict what decisions people will make when presented with certain choices. The simpler the choices are, the easier the decision is to make (and predict). Would you rather have $100 or a sharp stick in your arm? Not exactly hard to predict. Would you let me poke you in the arm with a sharp stick if I give you $100? Not quite as easy to predict.
If there are a variety of choices and they are equally desirable, the decision becomes more difficult to predict simply because the decision is based more on personal preference. Will your customer choose a blue one or a red one? It depends on what they prefer (although in the Western world, blue is generally a more popular color than red).
As a retailer, you want to be sure you offer enough variety to satisfy a broad spectrum of customers. However, the way you PRESENT that variety is critical because, when presented with too many choices, your customer may suffer what is known as The Paradox of Choice, a concept studied by psychologist Barry Schwartz in his 2004 book “The Paradox of Choice: Why More Is Less”. What happens is that, when too many choices are presented at the same time, a customer may become unable to make any choice at all. This could be from what is known as “analysis paralysis” in which they are constantly comparing, trying to figure out the best choice, or it could be simply that they are overwhelmed by the amount of input and cannot choose.
How does this relate to you and your website?