Forgetting isn’t a mistake, it’s a skill the brain uses on purpose. In new research from Flinders University, scientists discovered that the same chemical that helps us learn, dopamine, also helps us forget. Using tiny transparent worms called Caenorhabditis elegans, which share about 80% of their genes with humans, the team watched how memories form and fade inside the brain.⁠ ⁠ The worms were trained to associate a fruity smell with food. Normally, that memory fades with time. But when the worms were engineered to lack dopamine, or when dopamine couldn’t move properly between cells, the memory lasted much longer. The worms could still learn, but they couldn’t let go of what they learned.⁠ ⁠ Two dopamine receptors, called DOP-2 and DOP-3, turned out to be key. When both were turned off, the worms kept their memories far longer than normal. Even when dopamine was restored in only one type of brain cell, forgetting didn’t return to normal. The entire dopamine system had to work together...