Les just bought a megaphone of root beer. As he drinks from the giant cup, he eventually becomes full. One of his friend's comments, "If you don't stop drinking that stuff, you will get sick." Les replies, "Hey, I bought it, and I am not going to waste one drop of it." Les's behavior could best be described by which of the following mental biases?

According to my research on studies conducted by various behaviorists, I can say that based on the information provided within the question the mental bias that describes Les's behavior is called the Sink-Cost Fallacy. This fallacy/bias refers to when an individual relentlessly continues's a behavior solely because of the resources that they have invested, either being time, money, or effort. Which in this case since, Les invested money into the drink so he does not want to waste it even though it might make him sick.

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