More products should mean more sales. More categories should mean better navigation. More options should mean happier customers. Intuitively, this makes sense — and it’s wrong.
Psychologist Barry Schwartz coined the term “paradox of choice” to describe how increasing the number of options beyond a certain threshold makes people less likely to choose at all. In ecommerce, this paradox shows up every day: stores with hundreds of products and elaborate menus often convert worse than stores with focused catalogs and simple navigation.
The jam experiment and its ecommerce parallel
The classic study by Sheena Iyengar and Mark Lepper at a grocery store found that displaying 24 varieties of jam attracted more initial interest (60% of shoppers stopped to browse) but converted far worse (3% bought) compared to a display with 6 varieties (40% stopped, 30% bought). Ten times the conversion rate from fewer options.
The ecommerce parallel is direct. A collection page showing 200 products is the 24-jam table. The shopper sees the quantity, feels overwhelmed, and either picks something arbitrarily (often regretting it later) or leaves without buying. A collection showing 30 products, pre-filtered to match the shopper’s intent, is the 6-jam table. Fewer options, but each one is relevant, and the shopper can actually compare them.
How navigation creates overchoice
Navigation creates decision fatigue in three ways:
Too many top-level categories. A menu with 20 or 30 categories requires the shopper to scan all of them before choosing one. Each item is a potential path, and evaluating 30 paths is cognitive work. The shopper either picks randomly (missing the best category) or freezes (and uses search or leaves).
Too-deep hierarchy without guidance. A menu that goes four or five levels deep creates a chain of decisions: category → subcategory → sub-subcategory → sub-sub-subcategory → product. Each level is a choice, and the shopper has to trust that the path they’re on leads to the right products. A wrong choice at any level means backtracking — which feels like wasted effort.
Flat collection pages with no filtering. A shopper who successfully navigates to a collection page and then sees 200 products in a flat grid faces another wave of overchoice. Without filters or sorting, the shopper has to evaluate each product by scrolling, which is exhausting for more than 20 or 30 items.
The conversion cost of decision fatigue
Decision fatigue doesn’t make shoppers abandon immediately. It makes them browse longer, add fewer items to the cart, and abandon at higher rates. The shopper who spent 15 minutes browsing 200 products without narrowing down is less likely to buy than the shopper who spent 5 minutes browsing 30 relevant products and found three they liked.
There’s also a quality-of-decision effect. Shoppers suffering from decision fatigue tend to default to the cheapest option or the first option — not because it’s the best fit, but because they’ve exhausted their mental budget for evaluation. This leads to less satisfying purchases and higher return rates.
For store owners, the takeaway is counterintuitive: helping shoppers see fewer products (the right products, in the right context) leads to better outcomes than showing them everything. Navigation is the first tool for this — it filters the catalog before the shopper ever reaches a product page.
The 7±2 rule for menu design
George Miller’s research on working memory suggests that humans can hold about 7 (plus or minus 2) items in short-term memory at once. For menu design, this translates to a practical guideline: top-level menus with 5 to 9 items are easiest to scan and choose from.
This doesn’t mean a store with 15 categories must cut to 7. It means those 15 categories should be organized under 5 to 9 groups. The shopper evaluates the groups (manageable), chooses one, and then evaluates the categories within it (also manageable). Two small decisions instead of one overwhelming one.
On mobile, the constraint is even tighter. A tabbar holds 3 to 5 items. A slide menu’s first screen should show the top-level groups without scrolling. If the shopper has to scroll to see all the top-level categories, they can’t scan and compare them as a set — they have to remember what was above while looking at what’s below.
This article is part of the larger guide on Too many choices: how navigation can reduce decision fatigue.