An audience is first asked to write the last 2 digits of their social security number, and, second, to submit mock bids on items such as wine and chocolate. The half of the audience with higher two-digit numbers would submit bids that were between 60 percent and 120 percent higher than those of the other half. This is an example of:

Anchoring bias

Explanation: Anchoring bias is described as the tendency to focus on one value or idea known as the “anchor” and not adjust away from it sufficiently (the simple act of thinking of the first number strongly influences the second, even though there is no logical connection between them); It is also defined as the tendency of people to place subsequently refined answers to a given question close to the initially estimated answer, giving unduly weight to the initial answer, such as adjusting the initial estimate of 10% to 20% when 90% would have been more appropriate.

Some examples of anchors might include: real estate listing prices, initial cost estimates for development projects, salary of your last job etc.