Why the first and last tiles are seen and the rest skipped

An e-commerce category page displayed twelve product tiles in a row. Heat-map analysis showed the first two and last two tiles received sixty-eight percent of total fixations; the middle eight shared the remaining thirty-two percent. Products placed in positions five through nine were functionally invisible regardless of their ratings or reviews.

What everyone sees

Shoppers believe they scanned all twelve items equally. They attribute their click to product quality, not to tile position. The positional bias is invisible because the shopper feels that their gaze was thorough and their choice was deliberate.

What is actually happening

Murdock’s serial-position effect shows that items at the beginning of a list benefit from primacy (deeper encoding due to undivided attention) and items at the end benefit from recency (still held in working memory). Applied to visual layouts, Bar and Neta found that the same attentional gradient applies to spatial arrays: edge items receive disproportionate fixation because the visual system anchors at boundaries. Middle items fall into an attentional trough.

Why it stays hidden

The effect hides because the layout looks equitable. Each tile is the same size, with the same styling, implying equal opportunity. The serial-position bias is structural and neural, not visual, so the apparent fairness of the grid masks the profound inequality of the attention it distributes.