On a web page, an imaginary line causing a mental boundary. Enquiro's research demonstrates that fencing is a common behavior when scanning a search engine results page that presents images or graphic elements with straight sides.

An imaginary line causing a mental boundary. Fencing is created when the user visually scans through images and text in a straight line.

It seems we like to extend these straight lines to form mental boundaries that we use to divide up the page for scanning. In addition to creating scanning “ chunks ” , this also can have the effect of restricting scanning beyond the boundary. For example, look at the two heat maps above. In both cases, it appears the presence of an image created a “fence” that restricted scanning below it and led to greater scanning above.