Artificial Intelligence is every day getting smarter and smarter. Not only it is simulating precise behaviour and calculations but also making intelligent mistakes so players think the computer is more like them and less machine. However there's more to Artificial Intelligence than making the computer to simulate human intelligence (including our logic and analitical mistakes)... there's also the simulation of the marvelous human stupidity!
I was just thinking about a common sense action very common in Artificial Intelligence: searching. The first idea when you think about searching for something is about the most intelligent way for you to find that thing in the most optimal way. However this have been studied a lot in Artificial Intelligence and I will think mor about the "thing" that I will be looking for.
In games is very common for an artificially controlled character to know exactly what he is looking for. If he doesn't know what it is he is looking for then there will be very specific parameters to help the character decide which thing to search for. These parameters vary from very simple, specific, and concise (such as saying: always look for the key) to more complex and abstract (such as saying: look for the perfect job for you).
The second example about the perfect job is complex because it asks for personality, environment, social background, skills, ... and a lot of other factors to decide which is best (king of how it works in The Sims). The thing here is that all these calculations made in order to choose which desicion is right for the virtual character are based in what we think is obvious to choose given the circumstances... but the fact is that we humans are not always that obvious.
The reason why we are not that obvious is because we sometimes tend to look for things we already have. Is actually common sense... you don't look for things you own. If you need to know why, it's because you already looked for it and you already found it. The reasoning behind all the looking for things you already have is that it's human nature to look for something, it doesn't matter what it is.
The StandBy state doesn't exist for us, there's this thing we call "The big struggle for happiness" and it consists in looking for happiness until you die because you can never achieve it completely. So you may think that this is not always true and maybe you're right (after all this is more a philosophical subject than any other thing) but the deal is that it must have something of truth in it since it have been thought so many times.
An example for this not-logical kind of thinking is the search for love. Some people look for love, they get a lovely girlfriend/boyfriend, fall in love and get married... after a while they get bored, they start saying that they haven't found love and get divorced, in order to continue their search.
Back to games, let's call for a Stealth game example for this. How many times have you seen a guard searching further for a possible enemy? Probably the most common behaviour for a Stealth game guard is to have a predefined path, search places where he heard noises or saw something, and shoot if he sees you (or something significant enough to shoot at). There may be some random delays for certain states, such as resting, patroling, standing by, acting unaware... but nothing goes beyond this intelligently way of always knowing what to look for.
So what if the guard wanted to shoot the shadows just because he couldn't find enough stillness? What if the sim suddenly destroyed his bed because he can't find sleep? ... or what if the soldiers went out to the enemy base just because they couldn't find enough security in their own base? What I mean is... if what we want is to give a human approach to Artificial Intelligence, why can't we see this kind of behaviour mistakes? It is not common but still... it happens and could give some unpredictable fun to the game.