The sunk cost bias is a common fallacy that people fall victim to. It entails placing a higher value on an option because of the resources already invested in it, rather than rationally evaluating...Show moreThe sunk cost bias is a common fallacy that people fall victim to. It entails placing a higher value on an option because of the resources already invested in it, rather than rationally evaluating its current worth. This economic fallacy goes beyond financial investments and is found to also be present in romantic relationships. Our research investigates this effect, and whether age and gender play a role in it. This was investigated through a questionnaire with a total of 93 participants in the Netherlands. Our main hypothesis was that the temporal investment in the relationship significantly influences the likelihood of staying during difficult circumstances, such as a period of emotional distress or cheating. This prediction was confirmed. However, a difference in influence of temporal investment in the decision to stay in the relationship, between males and females, was not found to be significant. Moreover, age was only found to have a significant influence on the effect of temporal investment for the predicted length of staying. In conclusion, these findings demonstrate the presence of the sunk cost effect of temporal investment in romantic relationships, without a significant difference between males and females, or a significant effect of age that is attributable only to the sunk cost fallacy.Show less