That first impressions count is something most people do understand. That is takes 50 milliseconds to come to the conclusion that a website is great or not, is even for the most optimistic web designer shocking. Fifty milliseconds is a short, very short period of time.
On average, a human eye takes between 300 and 400 milliseconds to complete a single blink: We can blink some three to four times a second. Imagine determining the quality of a website in a fraction of a blink.
Hence, even if a website is highly usable and provides very useful information presented in a logical arrangement, this may fail to impress a user whose first impression of the site was negative.
According to a study by Gitte LindGaard et. al, published in Behavior and Technology (vol 25, no. 2 March April 2006), visual appeal can be assessed within 50ms, suggesting that website designers indeed have 50ms to make a good first impression based on the "halo" effect or "cognitive confirmation bias." If the first impression is good, the rest you observe is also good. In terms of websites, if the first impression of the site is good, visitors believe that the rest of the website is also good. It can also work the other way.
We do of course not know how it works when the website is loading. It may take a few seconds for a site to download completely, so when during the process of loading a site do we form our first impression?
Nevertheless, next time when you design a website, think of its first impression. If it is good, it may all work out in your favor.
We found a link to the article: http://www.ext.colostate.edu/conferences/ace-netc/lindgaard.pdf