I really enjoy finding powerful analogs between simple concepts and complex phenomenon. You know what I mean - like discovering that the process of designing cities shares similar characteristics to the growth slime molds (Ask Steven Johnson about this). The site Website Optimization offers a compelling example.

In this case it is the comparison between the actions of a male grain beetle looking for sex (honest) and the average Internet user looking for information. (Pirolli, P. (2007). "Information Foraging Theory: Adaptive Interaction with Information." New York, NY: Oxford University Press.)

It turns out that the patterns generated by the two behaviours are similar.

Switching when Information Scent Drops

Pirolli found that participants tend to not flit between web sites, but have more transitions within websites than without. Plotting the average scent ratings (rated by a panel of experts) of all the web pages visited, Pirolli found the reason why people switch to another site (information patch). Initially the information scent is high, but when the information scent falls below the average information scent in the pages encountered, users switch to another site or search engine (see Figure 3). Pirolli also found that starting with a high information scent was associated with longer runs at a web site (stickiness).

The High Cost of Low Information Scent

Web sites tend to be organized in hierarchical tree-like structures. The deeper and wider a site, the more costly the "false alarms" of low information scent become (see Information Scent). In fact, small improvements in the false alarm factor associated with individual links can have dramatic effects on the cost of surfing large hypertext collections (see Figure 4). In the example below, when the false alarm factor exceeds 10%, the search cost of following unproductive paths (backtracking, traversing up and down trees) goes from linear to exponential. Therefore a small improvement in information scent can have a dramatic impact on usability. Slow websites exacerbate this phenomenon, especially as site breadth and depth increase.

By equating what appears to be complex human behaviour with beetle behaviour we can see the profound impact small cues have on website usability.