Intuition is when we get a feeling about something, but that feeling does not come immediately with a justification. The essence is that you have some value judgement or decision, but you don't know where it came from.
It's an everyday word for something that is scientifically legitimate. Most of what goes on in our minds is unconscious. We're aware of only a tiny bit of it. Intuitive thoughts are churned up by your unconscious. Then it's up to your deliberate, conscious mind to decide what to do with them. Often, we get a feeling about something and then quickly construct a rationalization for it. We'll often believe that the rationalization is the cause of the belief or feeling, but often it's an afterthought-- a justification created by our conscious mind to explain the behaviour of our unconscious.
Okay, so intuitions come from unconscious processes. But where did these processes come from? What makes them be the way they are? Here's where things get interesting. The simplistic answer is that they are either innate or learned. It's not that black and white (for example, sometimes innate processes can be triggered by experience), but it's a good first-order approximation.
There are some things we didn't need to learn. A baby knows to suck at her mother's breast, and we naturally tend to dislike bitter tastes and peering over from great heights.
Long before psychology and cognitive science even existed, there was a debate between nature and nurture in the philosophical tradition (in parallel with the rationalist and empiricist debate in epistemology). And even today there is a debate, but now it's more nuanced. The question is no longer (or should no longer be) what is innate and what is learned, but rather what is the contribution of innateness and what is the contribution of our environment for a particular behaviour? For example, for how happy people are, 60% of it is innate, and 40% is your history and current situation.
So when you look over a cliff, or watch this video of a tower repair worker climbing a tower to get to work:
You might get a sense of the fear of heights. People I talk to about this video report a queasy, uncomfortable feeling in their guts and, interestingly, a tingly feeling in their feet. They didn't have to fall from a great height to learn this reaction. It evolved.
How do you know that great heights are dangerous? You can reason it out, but you also have a strong intuitive feeling that's hard to shake. For example, take this video. You know you're only watching a video, yet a part of your mind reacts as though you were really there. Knowing it's a video doesn't shake the feeling. I have friends who report that they can't even watch the whole thing. It's too harrowing.
Not all intuitive processes are innate. Many are learned.
Processes turn from conscious to unconscious all the time. In cognitive science we call this automatization. Things become automatic. It's very easy to understand with physical action. For example, the first time you tried to drive, you probably were overwhelmed with all of the things you needed to keep track of. After driving for years, however, the act of driving becomes completely automatized. First, you can stop thinking about which way to turn the wheel and start paying more attention to where you want to go. As routes get automatized, you might drive yourself all the way home without even realizing it happened- it is so automatic that you were able to think about completely different things the entire time.
Typing is another good example. When you get good at typing, you no longer think about where to put your fingers. Your attention is dedicated to thinking about what to write.
When things are automatized they get faster and more efficient. At that point, actually thinking about what you are doing consciously can mess you up. For example, if I try to think about where to put my feet when I'm running down stairs, I am more likely to make a mistake. It's better to just go for it.
So it is with physical actions. However, we also have many learned preferences that come with culture. Let's take table manners. In Britain, it's fine to eat with the fork in the left hand, tines down, and to push peas on to it with your knife. In America, this is not permissible. In Germany, you may hold the fork in your left hand, but with the tines up, even as you cut with the knife in your right hand.*
When you see someone using inappropriate table manners (by the standards of your culture), it evokes a mild disgust feeling. You also get a mild disgust feeling when smelling food that has gone bad. However, the former came from cultural conditioning, and the later is innate.
The main point I want to make with this post is that you can't tell just by feeling whether your intuition was learned or innate.
Why does this matter?
It matters for a few reasons.
1) We judge other people based on our intuitions.
Cultural practices become so ingrained that we mistakenly feel that they are "natural" in some normative sense, and that people from other cultures should abide by them. I'm not saying that every culture is equally good. I think there sometimes are objective reasons to think one way is better than another-- I'm American and I have my quibbles with American culture, for example. However I think we all would agree that many cultural practices are rather arbitrary traditions that have no objective right or wrong about them. Yet we have the same intuitive feelings about the arbitrary ones as we do about the objectively sensible ones.
2) We have to decide how to act in the world, and sometimes innate intuitions should be trusted more than learned ones.
Child-rearing is my favourite example. We learn child-rearing practices and grow up thinking that they are sacrosanct. For example, there is a belief in my own culture that pornography and nudity is bad for children to watch. I've looked, and I can find no research to support this. I've also found no research to disprove this-- I've found nothing at all. But we feel strongly about such things, and the feeling is not different from the feelings that are innate and evolved to protect and nurture the child. Some have intuitive notions that violence is a good way to discipline a child. They feel very strongly in favour of this, but in this case it's been shown that this is a pretty bad way to discipline a child (it makes the child more violent in the long term).
We have innate drives to breastfeed and to be affectionate with babies. Indeed, these things are good for babies. The innate feelings should be trusted (in most cases**) and the learned feelings should be questioned.
Unfortunately, we cannot tell the difference by simply looking into ourselves and examining the intuition and how it feels to us. It's a problem.
* When I go out to dinner at international conferences I like to try to guess where everyone at the table is from based on how they hold their knife and fork.
** Not all of our innate drives are good either, which complicates the problem. For an excellent book on the topic, I recommend Keith Stanovich's The Robot's Rebellion.
Stanovich, K. E. (2004). The Robot's Rebellion. The University of Chicago Press: Chicago, London.
Pictured: A water droplet. From Wikimedia Commons. For some reason it turned up when I searched for "intuition."