Short Sharp Science: A New Scientist Blog

How Google Instant knows what you want

MacGregor Campbell, reporter

If you've ever stared at the search box, trying to remember the name of that band your cousin mentioned the other day, Google can now help by completing your thought for you.

Google Instant, which launched on Wednesday, takes auto-complete to an extreme. As you type, possible completions of your query appear in the search box, followed by full potential search results for the search Google thinks you want to make. The old style of auto-complete still required you to select from among a number of candidates in a drop-down box. That function is still there, it's just augmented with actual search results before you're done typing.

As you might expect, searching for all the possible things you might end up wanting to search for is a bit of a headache on the engineering side of things. Google's Ben Gomes explained in this presentation both the technical challenges and some of the techniques his team used to get around them.

Gomes said that Google already serves billions of queries a day and that doing searches on predicted queries multiplies the server burden by a factor of between 10 and 20.

"How do we possibly do this without melting down our data centres?" asked Gomes.

Google's Othar Hansson said that they can ease much of this extra burden by combining a number of methods.

First, Google Instant relies on the fact that some searches are statistically more likely than others. Typing the letter "w", for example, is more likely to be finished with "weather" than "woolly mammoth".

Another clever tweak is the design of servers that keep track of which searches are already completed or are in progress on other servers, sharing information and reducing redundant searches. The team also worked out new cacheing methods to keep "canned" search results fresh, but also serve it quickly.

The result is slick, though a bit disorienting at first. By showing you a page full of results that changes as you type, Instant definitely will not help your case of information overload.

Alexandra Petri of the Washington Post compares it to an over-enthusiastic passenger in your car:

"Don't you want to turn left?" "Isn't this where we're going?" "Don't you want to stop at this light?"

Alexis Madrigal of the worries that by driving traffic to more statistically probable searches, Google Instant will lead to "a slight narrowing of our collective imagination."

Instant seems to fit with Google's overall strategy, reported by New Scientist in July, to know what you want before you do. Other search engines are thinking the same way, for example by using demographic information about you.

CEO Eric Schmidt said in a recent interview in the Wall Street Journal:

I actually think most people don't want Google to answer their questions. They want Google to tell them what they should be doing next.

By augmenting - perhaps interrupting - a searcher's train of thought, Google Instant brings this idea closer to reality.

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Arg. Hijacked... I've been making searches like that for a long time. Combining techniques to refine the searches while the user is typing... Can I sue them? Or will they sue me if they find my pages now?! lol


Predictivve searches based on intelligent selection of words?.. Ive been trying to get an OS dev crew on non Wintel based machiens to look at this since at least 2003. Itrs only in teh last few months that Ive found out teh idea was called random matrix theory. Otherwise known at letter count spectra analysis, otherwise known as neural net, etc.

So, Google, how will you handle the first sentient computers suing you for trying to patent their thoughts, especially if it turns out to be your own servers.?

Cant stand the abuse that patents are used for, P(S(x,y)n) I thought might as well give away, Open Source, as its sure cannot be patented under all present rules.

By the way, the method is called the Butler, or Secretary.


Rodney, I hope Google can keep ahead of your terrible spelling too.


The quote "Google Instant will lead to 'a slight narrowing of our collective imagination.'" could prove to be the understatement of the year. Google doesn't index every page on the web, so the idea 'if it's not on google it doesn't exist' is false.

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