"Emotional responses don't just pop out of nowhere," Greene said. "They have to be triggered by something. And one possibility is that you hear the words describing some event, you picture that event in your mind, and then you respond emotionally to that picture."
That's the key: Some dilemmas produce vivid images in our heads. And we're wired to respond emotionally to pictures. Take away the pictures — the brain goes into rational, calculation mode.
So when a verbal description is visually stimulating - that is, it causes the hearer to imagine the situation - the moral judgement becomes emotionally driven rather than rationally driven. The dilemmas used in the study asked participants to choose if one person died or five people died. In one scenario the participant was asked to flip a switch to make the decision. In the other, they were asked to push someone off a bridge.
The physical description and the activity of pushing someone off a bridge evoked a mental image and an emotional moral response, so the participants refused to kill one person to save five. However, when all it would take is the flip of a switch and the people were not vividly described, participants chose to sacrifice one person to save five.
I believe the application can be expanded beyond picture laden words to the quality of images.
Different images provide varying levels of emotional engagement and will evoke different moral responses. Take, for example, the image at the top of this post. It shows the different legal status of human trafficking around the world. From this perspective things don't look so bad in the US. We're nowhere near as bad Asia, Africa and South America.
What's the difference in your emotional response from the map to this picture?
What's your emotional reaction to this image?
Which image do you think would be more effective in working to stop human trafficking?
Why do you think we are so driven by emotions when a vivid image is involved?