To show that our subconscious really does work in this masochistic way, Kelly Goldsmith at Northwestern University in Evanston, Illinois, gave volunteers some word games. They were first asked to unscramble some sentences, some of which contained words like “sin” or “guilt” or “remorse”, while the others contained more neutral terms.

For the second part of the experiment, they were then shown fragments like “E N _ _ _” or “P L _ _ _ _ _ _” and asked to complete the word. Those who had previously unscrambled the sentences about wrong-doing were subsequently far more likely to fill in the gaps with words associated with desire – such as “enjoy” or “pleasure” – compared to other obvious possibilities, such as “enter” or “pleading”. In other words, rather than deflecting thoughts away from sin, the guilty subconscious started to think more lustfully.

Importantly, Goldsmith found those feelings translated to real sensual experiences. People primed with guilt said they enjoyed eating sweets in the lab more than others, for instance. The same was true even if Goldsmith subtly reminded them of the consequences on their health; looking at fitness magazines both increased their guilt, and their enjoyment, of the sweets. Nor was it limited to confectionary; the guilty words also made the volunteers take greater pleasure in looking at sexy pictures on an online dating website.

The “what-the-hell” effect

But the ironic twists of guilt don’t stop there. Besides enhancing your attraction to temptation, the feeling may also set off the so-called “what-the-hell” effect. This well-studied psychological phenomenon is the reason that you can’t stop at one slice of pie – you think that if you’ve failed once, you might as well give in completely.

When Roeline Kuijer and Jessica Boyce at the University of Canterbury in New Zealand, recently looked at eating habits, for instance, they found that participants who naturally associated chocolate cake with guilt had lower belief in their self-control than people who associated it with more positive feelings, like celebration. Over the next three months, that then became a self-fulfilling prophecy; although their intentions were exactly the same, the people who felt guiltier when thinking about chocolate were less successful at losing weight, compared to the people who viewed the chocolate with excitement rather than despair. The same was also true of another group who were trying to maintain a healthy weight; over 18 months, those who innocently enjoyed their food were also the least likely to pile on the pounds.