An episode of the BBC program Horizons featured the following experiment. A  researcher in a park with a lot of pedestrians invited passersby to examine an unopened  bottle of wine, which the researcher stated he had just purchased at a nearby  wine shop, and estimate the price the researcher had paid. Before participants actually  came up with their estimates, the researcher asked them to pull a ping pong ball  from a bag, keeping their eyes closed. The researcher indicated that each ball in the  bag had a number between 1 and 100 written on it. However, this was not true, as all  the ping pong balls had the same number.

The experiment was conducted twice, on two different days, with two different  groups of participants. The first group of people drew a ping pong ball with the number  10, while the second group drew a ping pong ball with the number 65. After seeing the  number on the ball, the researcher asked each participant for his or her estimate of the  wine’s price. The first group estimated the cost to be between $10 and $30, while the  second group guessed much higher, between $40 and $100. Discuss what psychological  phenomenon might explain this behavior pattern.