Is chocolate as addictive as heroin? Possibly. In a new study, mice willingly subjected themselves to electrical shocks in pursuit of a chocolate treat.
Italian researchers set out to discover just how much compulsive behavior plays a role in eating disorders. Rossella Ventura, leader of the research team at the Santa Lucia Foundation in Rome, took two sets of mice - the experimental group was starved while the control was fed normally - and trained them to choose between two chambers in a maze. The first chamber was empty while the second had a bit of chocolate inside. Once this conditioning was established, they added a mild electric shock to the chocolate room.
They then allowed the starved mice to eat their way back to normal weight and let both sets into the maze. The mice that had been well-fed throughout experienced the shock and quickly learned to avoid the chocolate chamber. The previously starved mice, on the other hand, fought through the pain in pursuit of the chocolate, despite the fact that they were now being fed adequately elsewhere.
Ventura explains that this is all about the effects of compulsive behavior:
"We used a new model of compulsive behavior to test whether a previous stressful experience of hunger might override a conditioned response to avoid a certain kind of food - in this case, chocolate."
In other words, this study suggests how stressful stimuli - such as memories of starvation - can impact otherwise rational decision-making. Ventura believes this willingness to ignore negative consequences in pursuit of food even when there is no great need for it demonstrates part of the behavior components that underlie eating disorders in humans and animals.