When Dias gave the trained mice a whiff of acetophenone, they tended to freeze in their tracks. Dias also found that a whiff of acetophenone made the mice more prone to startle at a loud noise. In other trials, Dias would pump an alcohol-like scent called propanol into the chamber instead, without giving the mice a shock. They didn't learn to fear that odor. Ten days after the training ended, researchers from Emory's animal resources department paid Dias a visit. They collected sperm from the trained mice and headed off to their own lab. There they injected the sperm into mouse eggs, which they then implanted into females. Later, after the pups had matured, Dias gave them a behavioral exam, too. Like their fathers, the new generation of mice was sensitive to acetophenone. Smelling it made them more likely to get startled by a loud sound, even though he had not trained the mice to make that association. When Dias allowed this new generation of mice to mate, the grandchildren of the original frightened males also turned out to be sensitive to acetophenone.