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Have you ever wanted to quit something, but you weren’t able to do it because there was already too much money, effort or time invested into it? Well, you are not alone! This quite common phenomenon is known as the sunk cost fallacy. The concept follows the idea that a person or a group of people choose to intentionally pursue further investments or commitments based on the aversion to waste the resources that were previously invested. One might ask, why do we incur in this fallacy in the first place? We’ll explore different concepts that might help us answer this question. 

The first concept to analyse is loss aversion. Loss aversion is usually related with investors, but it can apply to anyone. It’s the tendency to have a stronger preference in avoiding losses rather than acquiring the equivalent gains, simply because the “pain” of the loss is higher than the reward felt from a gain. In situations of loss aversion, three regions of the brain are activated: the striatum, which processes losses, the amygdala, which processes fear, and the insula, which makes individuals avoid some behaviours; neuroscientists also noted that this last region is much more activated in situations that might be a loss when comparing with the equivalent gain. This will make most individuals carefully consider risky actions and try to avoid losses. Additionally, as explained above, since the costs in our minds weigh more than the benefits, we might have the urge to make the most out of our resources and stay away from wastefulness. 

The different regions of the brain and their respective functions 

For example, when we are in the middle of a book that we hate, we often keep reading it until the end, just because we don’t want to waste the time or the money that we already invested in that book. This just goes to show that, sometimes we continue to put effort into something when we might be better off leaving it, just because we don’t want to feel like we are losing or quitting on the costs that we already incurred despite, most of the times, those costs being unrecoverable. 
As the writer and comedian James Colley revealed to The Guardian, “At some point it becomes a calculation of ego. When a book is finished it becomes a trophy. When it’s left half-finished it becomes an albatross. It occupies your mind like the tell-tale heart, mocking you, symbolising your failure”. 

This fallacy, however, doesn’t only affect individual decisions but can also have considerable proportions by affecting governments and larger projects. One example of this is the development of the airplane Concorde, which resulted in the partnership between the UK and France and had an initial cost of 100 million dollars. However, as the project developed, more costs accumulated, having a final value of 1.6 billion dollars. Even though it was a technical improvement, it reveals the sunk cost fallacy because, as the costs were incurred, they realised that it wouldn’t pay off, but they continued with the project.  This plane was retired after only 34 years, and it was so expensive that was never profitable. In this example, the governments of France and the UK were victims of the sunk cost fallacy, as despite the understanding of the unprofitability of the project they continued it. This could be justified not only by the feeling of wasted resources but also by the pressure that could arise from the bad investments of taxpayers ‘money. 

The Airplane Concorde being fully operational despite costly drawbacks 

This example illustrates the second concept, escalation of commitment. This tendency happens when some individuals might stick with a decision previously made because they feel the pressure to remain and to “honour” that commitment, such as in the case referred above, where even after new information notifies them that the previous decision might not be the best to follow.  

Another application of the sunk cost fallacy is related with the third concept called gambler’s conceit. This idea expresses that a gambler believes that he will be able to stop his risky behaviour while still engaging in it. Let’s say that you went to a casino and lost 100 dollars gambling. Your odds remain the same as when you started. Despite this, the tendency is to keep gambling until you recover from that loss because you already risked that money into the game, and you might experience loss aversion (feeling of loss greater than the one of gain). Besides that, according to the gambler’s conceit, while you are playing, you believe that you are still able to stop and that you will do it once you achieve gains, but when that happens, results show that you are unlikely to stop. 

In this illustration, you are also letting your past actions and losses influence your recent decisions leading to irrational behaviour, and it can be described as an entrapment situation, in which we endure the losses, in the hope of a later rescue and success by further investment. 

As seen throughout this article, it is rooted in our brains a powerful loss aversion. This neurological feature might have had a significant role in assuring our survival as a species, as it allowed us to avoid risky behaviour. However, it is also at the core of the sunk cost fallacy, not allowing us to put our rationality into practice and leaving us stranded to our past and immutable actions. 

Whether you are in the middle of a boring book, in a losing streak at the casino or you simply invested too much in a project that no longer makes sense, we hope this article can help you. 

Sources: The Guardian, Forbes & Corporate Finance Institute


Afonso Serrano

Daniel Calado

Mariana Gomes


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