The number that tricks you
The first number you see quietly changes every number you guess, even when you know it's random. Spin the wheel, make four guesses about the UAE, then see how real visitors who saw a different number answered.
What just happened: anchoring
When we don't know an answer, we start from whatever number is in front of us and adjust. We almost always stop adjusting too early, so we end up close to where we started.
In 1974 the psychologists Amos Tversky and Daniel Kahneman spun a wheel of fortune in front of people. It was set to stop on 10 or 65. Then they asked what percentage of United Nations members were African countries. People who saw 10 guessed 25% on average. People who saw 65 guessed 45%.
Our wheel was not really random. Each visitor is put in a "low" or "high" group for each question, and the wheel stops on that group's number. That's how we can compare the two groups fairly.
The effect shows up even when people are told the number is meaningless, and even for experts. Being warned helps a little, but not much.
Where anchors hide in real life
The crossed-out price is an anchor. It makes AED 499 feel like a bargain. The real question is: would you pay AED 499 if you had never seen the 999? Check the price in other shops first.
In a negotiation the first number on the table tends to pull the final deal towards it. If you've done your research, it can help to name a well-founded number first instead of reacting to theirs.
An asking price for a used car or a flat sets the starting point for everyone, even professionals. In one study, experienced estate agents valued the same house higher when they were shown a higher listing price.
Make your own estimate before you look at theirs. Ask "what would make the opposite true?" Look up a few real reference prices. And give yourself a moment before you answer.
Sources: Tversky, A. and Kahneman, D. (1974) "Judgment under Uncertainty: Heuristics and Biases", Science 185 (the wheel of fortune study); Galinsky, A. and Mussweiler, T. (2001) "First offers as anchors", Journal of Personality and Social Psychology; Northcraft, G. and Neale, M. (1987) on estate agents and listing prices, Organizational Behavior and Human Decision Processes. Answers: Burj Khalifa height 828 m (Emaar and the Council on Tall Buildings and Urban Habitat); 82 domes at the Sheikh Zayed Grand Mosque (Sheikh Zayed Grand Mosque Centre); Qasr Al Hosn's watchtower built around the 1760s (Department of Culture and Tourism Abu Dhabi); the Hope Probe travelled about 493 million km to reach Mars in February 2021 (Mohammed bin Rashid Space Centre, Emirates Mars Mission). Visitor answers are anonymous counts and are a live demonstration, not a scientific study.