Are Sunk Costs In Relationships Costing You Your Happiness?

How many times have you heard about a friend, or a celebrity, or an acquaintance that has broken up from a long term relationship, only to get back together with the same partner a few days or weeks later, and then break up again? Or maybe you are, or have been, in this “on-and-off-again” cyclic relationship. Why is it that people find themselves in this, frequently toxic, situation? Well, if you are familiar with this form of behavior, then you are familiar with the sunk cost fallacy.

Although often applied to money, Brian Sweis’s article, “Sensitivity to sunk costs in mice, rats, and humans,” explains that sunk costs are broadly defined as “irrecoverable investments that should not influence decisions, because decisions should be made on the basis of expected future consequences” (Sweis et al., 2018). The “fallacy” is when the effect is instigating one to continue to do something that makes the situation worse off, such as throwing away good time, money, or effort with the bad, in attempt to salvage the effort or money already invested. This fallacy can also be applied to romantic relationships: staying with a partner because of the time and effort that has already been put into the relationship, despite how unhappy you might be now.

Drake Baer’s article, “The Fallacy That Keeps People in Unhappy Relationships,” mentions a study that asked participants in four groups whether they would stay or leave an “increasingly sexless, hostile marriage of ten years” (Baer, 2016) after one of these scenarios were provided per group: one-year marriage, money involved (from house), effort involved, and a control. It was found that 25% of the control group would stay while 35% of money and effort groups would stay (Baer, 2016). These findings support that not only is it the amount of time you have been together, but it is also the effort and monetary investments that make it harder to break up with a partner that is no longer suitable.

Not only is this phenomenon displayed in humans, but Sweis et al. found that it is conserved across species (mice and rats, as well). This begs the question: why is this sunk cost behavior conserved in humans (and nonhuman animals) if it does not serve to benefit the individual? Baer offers a potential answer to this question, by introducing the evolutionary behavior of loss aversion: “organisms that favored avoiding threats over maximizing gains were more likely to hand their genes down to us” (Baer, 2016). This not only provides an insight into sunk cost behavior in humans, but also potentially why Sweis et al. saw this behavior conserved across the species they studied.

Reference:

https://www.thecut.com/2016/12/why-people-stay-in-unhappy-relationships.html