Does this blog post smell good?

Take a whiff, what does this blog post smell like to you? Does it have a strong and promising aroma, or a weak odor? Perhaps as you read on, the scent will get stronger and you’ll find yourself feasting. Alternatively, the smell will dissipate, and you’ll find yourself snacking somewhere else.

All this obscurity is likely confusing your nose, so let me get to the point. Back in the early 1990s, Stuart Card, Peter Pirolli and their colleagues at the Palo Alto Research Center (the same guys who gave us the laser printer, the GUI, and Ethernet) were struck by the analogies between the ways humans search for information, and the way other animals search for food. Specifically, they took theories of optimal foraging from biology and applied them to human search strategies for finding information online.

Optimal foraging theories in biology are models of how animals search for food using a series of cost-benefit analyses. The claim is not that animals actually perform these analyses, only that they act as if they were. In other words, these models may not describe how the animals actually ‘think’, but they do describe how the animals behave. The same applies to us when we are seeking information. Information foraging theories are not (at least they need not) be theories of how we actually think while we search out information, they simply describe how we in fact behave.

Consider the idea of information scent that I started this post with. You’ve probably never asked yourself what a website smells like, but of course smell is only a metaphor here. The informational scent of a page is your estimation of its informational value—how likely it is to provide you with the information you want. This estimation is made on the basis of cues, and the assessment determines whether you keep reading, or move on to a different page. As Jakob Nielsen writes, “the scent must keep getting stronger and stronger, or people give up. Progress must seem rapid enough to be worth the predicted effort required to reach the destination.” (1)

Of course how likely a predator is to keep following one trail depends not just on the scent of that trail, but also on how many other promising trails are available—so too with information foraging. In the early history of the Internet, informative websites were rare and hard to find. This promoted feasting—staying on one website for a long time in order to entirely digest its content. However, here in the age of Google, Twitter, Reddit and Facebook, information is plentiful and easy to find. This promotes information snacking—jumping from site to site absorbing only a small amount of content from each one. The idea is that when information is sparse, or just hard to find, people are willing to stay with a single source longer because the costs of relocating are high, but when information is plentiful and easy to find, the costs of moving on are very small. So people’s information foraging behavior is governed by a cost benefit analysis—the estimated benefit of the site (its informational scent) versus the cost of moving on to a different site. When the cost of moving on is high, people will continue following even a weak scent, but when the cost of moving on is very low, only the strongest scents will attract prolonged attention.

There’s much more that could be said, but that’s enough for a brief overview. We’re at the end now. If you’ve read this far, then the answer to the question we started with is: this blog post smells pretty good.

Sources and other scent trails:

Jakob Nielsen’s Alert Box Article cited above:



Slate article on our inborn desire to seek information:

For those looking to forage a little further, Peter Pirolli’s book is available in web format from the SFU library:


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