Trauma can scar people so indelibly that their children are affected. History provides examples of generations traumatized by war and starvation whose children experience altered physiology. Emory University researchers Kerry Ressler and Brian Dias have showed that an experience linked with a smell can modify the architecture of the nervous systems in later generations.

The researchers have found an instance of animals passing on more specific information about a traumatic experience to their offspring. That information comes not through social communication, but through inheritance. Researchers have found that when a mouse learns to become afraid of a certain odor, his or her pups will be more sensitive to that odor, even though the pups have never encountered it.