But if sugar is placed in the end of the dark tunnel, and something the flies dislike is placed in the end of the light tunnel, the flies will eventually learn to fly towards darkness rather than light.
Hvis nogle af fluerne ikke er placeret i enden af den lyse tunnel, og der er placeret sukker i enden af den mørke, lærer fluerne efterhånden at flyve mod mørke frem for mod lyset.