Hedwig von Restorff was a German psychologist, trained in the Gestalt tradition. Gestalt psychology can be summed up as "the whole is greater than the sum of its parts" (though interestingly, the original quote actually translates to "the whole is other than the sum of its parts"). That is, Gestalt psychologists focus on overall constructs, and how people perceive individual pieces as part of a whole. They also study topics like pattern recognition, and even biases in perceiving patterns and order where they do not exist. It goes back to the idea that humans like order, and will perceive the world in such a way as to bring order to chaos.
Unfortunately, we don't a lot about Restorff's contributions to the field of psychology, because much of her work was never translated into English. However, she is best known for the isolation paradigm, also known as the Von Restorff effect. This occurs when we remember an object or item in a list better because it is unusual.
|Either a demonstration of this effect, or a Prog Rock album cover - you be the judge.
Though this seems like a very simple concept, it has widespread applications. It is frequently applied to advertising, which is perhaps one reason why advertising can seem very off-the-wall and random. Marketers have to do something different to set themselves apart. As other marketers do the same thing, "weird" becomes the new normal, so marketers have to keep pushing the envelope to make their product, or at least its advertising, seem different.
This concept can also work in concert with other cognitive biases, like the availability heuristic, where something seems common or likely because it is easily remembered. This might explain why people tend to focus on rare events of a behavior instead of more common outcomes. For instance, among people who are anti-vaccination, this would explain why they focus on the rare serious side effects that can occur from vaccination, as opposed to the more common illness that comes along with not not being vaccinated. The serious side effects, like Guillain–Barré syndrome is memorable, because it is so unusual. But your odds of having that side effect are ridiculously small: about 1 in 1 million.
This is still an important area of research today. Restorff's legacy lives on.