One of their most striking experiments asked participants to spin a ‘wheel of fortune’, which landed on a number between 1 and 100, before considering general knowledge questions – such as estimating the number of African countries that are represented in the UN. The wheel of fortune should, of course, have had no influence on their answers – but the effect was quite profound. The lower the quantity on the wheel, the smaller their estimate – the arbitrary value had planted a figure in their mind, ‘anchoring’ their judgement.6
