why do our headaches persist after taking a onecent aspirin but disappear when we take a 50cent aspirinwhy does recalling the ten commandments reduce our tendency to lie even when we couldnt possibly be caughtwhy do we splurge on a lavish meal but cut coupons to save twentyfive cents on a can of soupwhy do we go back for second helpings at the unlimited buffet even when our stomachs are already fulland how did we ever start spending 415 on a cup of coffee when just a few years ago we used to pay less than a dollarwhen it comes to making decisions in our lives we think were in control we think were making smart rational choices but are wein a series of illuminating often surprising experiments mit behavioral economist dan ariely refutes the common assumption that we behave in fundamentally rational ways blending everyday experience with groundbreaking research ariely explains how expectations emotions social norms and other invisible seemingly illogical forces skew our reasoning abilitiesnot only do we make astonishingly simple mistakes every day but we make the same types of mistakes ariely discovers we consistently overpay underestimate and procrastinate we fail to understand the profound effects of our emotions on what we want and we overvalue what we already own yet these misguided behaviors are neither random nor senseless theyre systematic and predictablemaking us predictably irrationalfrom drinking coffee to losing weight from buying a car to choosing a romantic partner ariely explains how to break through these systematic patterns of thought to make better decisions predictably irrational will change the way we interact with the worldone small decision at a time