There is such a thing.

First patented in 1887, the idea of a true image mirror still was never seen as more than a curiosity until a key benefit was discovered by founder John Walter. What he saw was that his "real self" was present in the true image; a big contrast over the "self" seen in a flat, traditional mirror.

You probably knew that. But did you know that visitors to your web site decide in 50 milliseconds whether your site is any good?

Lindgaard and her team presented volunteers with the briefest glimpses of web pages previously rated as being either easy on the eye or particularly jarring, and asked them to rate the websites on a sliding scale of visual appeal. Even though the images flashed up for just 50 milliseconds, roughly the duration of a single frame of standard television footage, their verdicts tallied well with judgements made after a longer period of scrutiny. . .

For a typical commercial website, 60% of traffic comes from search engines such as Google, says Marc Caudron of London web-design agency Pod1. This makes a user's first impression even more critical, he explains. "You'll get a list of sites, click the top one, and then either say 'I've engaged' and give it a few more seconds, or just go back to Google," he says.

The lasting effect of first impressions is known to psychologists as the 'halo effect': if you can snare people with an attractive design, they are more likely to overlook other minor faults with the site, and may rate its actual content (such as this article, for example) more favourably.

This is because of 'cognitive bias', Lindgaard explains. People enjoy being right, so continuing to use a website that gave a good first impression helps to 'prove' to themselves that they made a good initial decision. The phenomenon pervades our society; even doctors have been shown to follow their initial hunches, Lindgaard says, relying heavily on a patient's most immediately obvious symptom when making a diagnosis. "It's awfully scary stuff, but the tendency to jump to conclusions is far more widespread than we realize," she says.

What's good?

Caudron suggests that the amount of graphics on the page should be strictly limited, perhaps to a single eye-catching image. . .

These days, enlightened web users want to see a "puritan" approach, Caudron adds. It's about getting information across in the quickest, simplest way possible. For this reason, many commercial websites now follow a fairly regular set of rules. For example, westerners tend to look at the top-left corner of a page first, so that's where the company logo should go. And most users also expect to see a search function in the top right.

Of course, says Caudron, the other golden rule is to make sure that your web pages load quickly, otherwise your customers might not stick around long enough to make that coveted first impression.

Mirror, mirror on the other side of this tube, show me my true self. Does this site suck? It follows the rules - 1 image, logo left, search right - but maybe it needs more white space? Different colors? Greater contrasts? Does the form reflect or at least complement the function? When you first glimpsed this site what did you think? Have your first impressions proved to be correct?