Why Does Having So Little Mean So Much?

Have you ever been online shopping and come across a product where there was only 1 left? Or perhaps, there were 4 items in stock and 3 have supposedly sold today? Or even, there were 12 items in stock but 143 people have looked at them in the last hour? This is something I experienced recently when trying to purchase a book and speakers online from shopping sites such as 'Amazon'.

All of these techniques come down to the fundamental implication of scarcity. Specifically, limited-quantity scarcity.
Parker & Lehmann (2011) investigated the use of scarcity within a supermarket store. Participants were required to select the items they wanted from options available within the simulated store and subsequently explain their choices. They found that people chose the more scarce items. The graph below demonstrates that the relative scarcity level impacts choice, however, the type of wine did not.

According to this principle we place higher values on items that are rare or harder to obtain. This is emphasised when competition for the available desired item is fierce. This is a form of social proof which suggests that we look to others to see how we should act and behave. Therefore, the scarcity of a product is seen to indicate that the product is good and therefore desirable because others want it. When we want something we can't have, this drives us to want it even more. This is why companies, such as 'Amazon', use scarcity as an effective method to increase sales. Cialdini (1993) describes this as a 'limited number' tactic, whereby customers are lead to believe items are in short supply and will inevitably run out of stock soon. He suggests that the worth we place on items or opportunities is directly linked to the availability of them.

References:

Cialdini, R. B. (1993). Influence: The psychology of persuasion. New York: Morrow.

Parker, J. R., & Lehmann, D. R. (2011). When shelf-based scarcity impacts consumer preferences. Journal of Retailing, 87(2), 142-155.