"
We had MBA students write down the last two digits of their social security number (mine are seven and nine) and then asked them whether they would pay that number in dollars (in my case $79) for, say, a bottle of Côtes du Rhône 1998. We then asked them to write down the maximum amount they would to pay for the product.
Our results? The mere mention of the last two digits of their social-security number influenced how much they were willing to spend. Students with numbers ending between 80 and 99 placed bids that were 216 to 346 per cent higher than those bids from students with numbers from 1-20.
"- Dan Ariely: Human habits - Wired.co.uk
