The release of thumbnails in FAST has generated quite a bit buzz in the blogosphere. The topic of visual search interfaces in one that is worthy of discussion. When users first see a search result that contains thumbnails, or any other graphic, the reaction is normally very positive. Aesthetics aside, do thumbnails actually improve the search experience? The good news is that there has been quite a bit of research conducted on this topic.
Many researchers have experimented with incorporating thumbnails as a memory aid in browser history and this has proven successful in helping people quickly locate sites that they had already visited. Other efforts that attempt to use thumbnails to improve search results have not been successful, however. A study by Czerwinski et al. (1999) showed that thumbnails offered users no benefit at all. A subsequent study by Dziadosz and Chandrasedar (2002) used result listings from Microsoft Search to compare textual summaries alone, thumbnails alone, and thumbnails with summaries. The study revealed that Thumbnails combined with summaries offered no advantage in assessing relevance. A study conducted by Woodruff (2001) indicated that thumbnails are useful for certain types of content such as images, but not text. Kaasten (2002) conducted a study that indicated thumbnails were not helpful because they are too small to present readable text. A VP at Google related a story in 2003 about testing thumbnails beside search engine results; after 24 hours of testing, the experiment was stopped because it was immediately detected that users where much slower on pages with the thumbnails because fewer hits were appearing “above the fold”. In other words, thumbnails where taking up valuable real estate. Interestingly, Google just updated Google.com last week to include thumbnails, but they are only accessible by clicking on a link to view them.
Studies aside, the value of presenting a thumbnail of the first page of a document is suspect. The relevant section of the document is rarely on the first page. The first page or slide can provide the title of the document, but this is typically already presented in the standard search result interface. In the case of Google above it’s more useful, because you are being presented with the most relevant webpage in the website.
So in summary, my view is that thumbnails are indeed useful, but more so for graphics or in identifying content that you’ve already worked with.
What about previews? That’s a different story.
Tags: Search Usability
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