Let's say you want to try to sneak something past a person, but don't want to take the rap for it if you're caught. You need to make use of the serial position effect. The effect reveals how our memories can be tricked by listing items in a certain way. Put whatever it is that you want to hide in the right spot, and you'll be doing your duty while still getting away with something.
The serial position effect is a simple, well-documented effect first observed in the late 1800s by Hermann Ebbinghaus. Give a people a list of words, and see which ones they remember. After a few tests, researchers found that there was a definite pattern to which words they recalled. The first words on the list were the well represented. The last words, which the patients had just seen or heard, were also remembered fairly well. The middle section was a blur for most people.
This seems like common sense. If I were trying to sneak a something into a list or a line and I didn't want it remembered, I'd put it towards the middle. Most people would. The experiment is repeatable with everything from lists of names to tv commercials. After any set of commercials, people are most likely to recall the first ones and the last ones.
Psychologists argue, though, about what exact brain process causes this effect. The debate is split into two sides: those who believe it's all part of one phenomenon, and those who think there are two phenomena at work. Those who believe that it's all one brain process think that the middle words are the ones that have the least advantage in the learning process. People learn as they go. The most recent words stay fresh, the earliest ones are practiced, and the middle ones are weak. Or, possibly, the beginning and end words are categorized as most important by the listener, and given priority.
Those who believe there are two processes involved think that the first words are considered important - and so are put in long-term memory storage. The most recent words are put in short-term storage and are fresh for the quiz. The words in the middle are put in short-term storage as well, but are eventually lost as the list gets longer, and so aren't remembered.
While there's no definite way to be sure which theory is correct, the idea of two cognitive processes gets a boost from the fact that people with very mild dementia seem to have no problem remembering words at the beginning of the list, but can't quite remember words at the end. This indicates that there are different brain processes at work, and only the second one is affected in the earliest stages of dementia.
Meanwhile, when I'm given a list of things to remember, if there's any real break between the list and the need to recall it, I generally forget that I've been told anything at all. What brain process does that involve?