We are more inclined to criticize people’s wrongdoings than recognize their good deeds. And this moralistic tendency isn't just cultural. Indeed, a team of neurobiologists from Duke University have located an area of the brain that plays a special role in our judgement skills. Why is it easier to criticize others?

The study conducted by Lawrence Ngo and his team is the first to use neuroscience research tools to try to explain why people judge actions that lead to negative consequences to be more intentional than those that yield positive results. The young man that helps an old lady to cross the street… “Isn’t he doing it in his own self-interest?" This thought (negative judgement) comes to mind more quickly than positive judgement: “Oh, isn’t he nice!”

For this research, the team of neurobiologists chose this type of scenario, commonly used in experimental philosophy: the vice-president of a company goes to see the CEO and tells him, “We are thinking of starting a new program. It will allow us to significantly increase our profits, but will also harm the environment.” The president answers: “I don’t care about harming the environment. I just want to make as much profit as possible. Let’s start the new program.” Participants are then asked the following question: did the president intentionally harm the environment? 82% of participants answer “yes” to this question. Now let’s replace the word “harm” by “help”… In this case, only 23% of participants consider the effect of the president’s action on the environment to be intentional. Yet in both cases, the CEO is completely indifferent to the environmental consequences. There is no logical reason for us to imagine greater intention behind a wrongful action than a helpful one. This is what we call the “Knobe effect” (from the name of the philosopher that invented the scenario); namely that moral considerations guide how we attribute mental states.

To explain this paradox, the researchers, in addition to two other experiments, used a functional MRI to analyze brain activity in 20 participants (average age: 24; 10 men and 10 women) while they read forty other scenarios similar to the one described above. The participants were asked to rate the degree of intentionality of the action on a scale from 1 (not at all intentional) to 8 (completely intentional). They observed that when a person first reads the story and judges whether the actions of the characters deserve to be criticized, his or her amygdala, an area of the brain closely tied to the control of emotions, is activated. The more the person is affected by the story, the higher the activation in this area. On the contrary, when the actions are considered to be positive, the amygdala is less active.

How can we explain the difference? According to the research team, it’s due to the fact that we are more rational when judging positive actions because we believe them to be the result of other self-serving actions (in the CEO scenario, helping the environment is perceived as an involuntary side effect). And that’s why we’re faster to blame people for their actions than to give them credit.