深入浅出Python(英文影印版)

.　　Neurons fire. Emotions crank up. Chemicals surge.
　　And that's how your brain knows...
　　This must be important! Don't forget it!
　　But imagine you're at home, or in a library. It's a safe, warm, tiger-free zone. You're studying. Getting ready for an exam. Or trying to learn some tough technical topic your boss thinks will take a week, ten days at the most.
　　Just one problem. Your brain's trying to do you a big favor. It's trying to make sure that this obvious_ly non-important content doesn't clutter up scarce resources. Resources that are better spent storing the really big things. Like tigers. Like the danger of fire. Like how you should never have posted those "party" photos on your Facebook page. And there's no simple way to tell your brain, "Hey brain, thank you very much, but no matter how dull this book is, and how little I'm registering on the emotional Richter scale right now, I really do want you to keep this stuff around."
　　We think of a "Head First" reader as learner.
　　So what does it take to learn something? First, you have to get it, then make sure you don't forgetit. It's not about pushing facts into your head. Based on the latest research in cognitive science, neurobiology, and educational psychology, learning takes a lot more than text on a page. We know what turns your brain on.
　　Some of the Head First learning principles:
　　Make it visual, Images are far more memorable than words alone, and make learning much more effective (up to 89% improvement in recall and transfer studies). It also makes things more understandable. Put the words within or near the graphics they relate to, rather than on the bottom or on another page, and learners will be up to twice as likely to solve problems related to the content.
　　Use a conversational and personalized style, In recent studies, student5 performed up to 40% better on post-learning tests if the content spoke directly to the reader, using a first-person, conversational style rather than taking a formal tone. Tell stories instead of lecturing. Use casual language. Don't take yourself too seriously. Which would you pay more attention to: a stimulating dinner party companion or a lecture?
　　Get the learner to think more deeply, in other words, unless you actively flex your neurons, nothing much happens in your head. A reader has to be motivated, engaged, curious, and inspired to solve problems, draw conclusions, and generate new knowledge. And for that, you need challenges, exercises, and thought-provoking questions, and activities that involve both sides of the brain and multiple senses.
　　Get-and keep-the reader's attention, We've all had the"l really want to learn this but I can't stay awake past page one" experience. Your brain pays attention to things that are out of the ordinary, interesting, strange, eye-catching, unexpected. Learning a new, tough, technical topic doesn't have to be boring. Your brain will learn much more quickly if it's not.
　　Touch their emotions. We now know that your ability to remember something is largely dependent on its emotional content. You remember what you care about. You remember when you feel something. No, we're not talking heart-wrenching stories about a boy and his dog. We're talking emotions like surprise, curiosity, fun, "what the...?", and the feeling of"I Rule!" that comes when you solve a puzzle,learn something everybody else thinks is hard, or realize you know something that "I'm more technical than thou"Bob from engineering doesn't.
　　Metacognition: thinking about thinking
　　If you really want to learn, and you want to learn more quickly and more deeply, pay attention to how you pay attention. Think about how you think. Learn how you learn.
　　Most of us did not take courses on metacognition or learning theory when we were growing up. We were expected to learn, but rarely taught to learn.
　　But we assume that if you're holding this book, you really want to learn how to design user-friendly websites. And you probably don't want to spend a lot of time. If you want to use what you read in this book, you need to remember what you read. And for that, you've got to understand it. To get the most from this book, or any book or learning experience, take responsibility for your brain.Your brain on this content.
　　The trick is to get your brain to see the new material you're learning as Really Important. Crucial to your well-being. As important as a tiger. Otherwise, you're in for a constant battle, with your brain doing its best to keep the new content from sticking.
　　So just how DO you get your brain to treat programming like it was a hungry tiger?
　　There's the slow, tedious way, or the faster, more effective way. The slow way is about sheer repetition. You obviously know that you are able to learn and remember even the dullest of topics if you keep pounding the same thing into your brain. With enough repetition, your brain says, "This doesn'teel important to him, but he keeps looking at the same thing over and over and over, so I suppose it must be."
　　The faster way is to do anything that increases brain activity, especially different types of brain activity. The things on the previous page are a big part of the solution, and they're all things that have been proven to help your brain work in your favor. For example, studies show that putting words within the pictures they describe (as opposed to somewhere else in the page, like a caption or in the body text) causes your brain to try to makes sense of how the words and picture relate, and this causes more neurons to fire. More neurons firing = more chances for your brain to get that this is something worth paying attention to, and possibly recording.
　　A conversational style helps because people tend to pay more attention when they perceive that they're in a conversation, since they're expected to follow along and hold up their end. The amazing thing is, your brain doesn't necessarily care that the "conversation" is between you and a book! On the other hand, if the writing style is formal and dry, your brain perceives it the same way you experience being lectured to while sitting in a roomful of passive attendees. No need to stay awake.
　　But pictures and conversational style are just the beginning...
　　Here's what WE did:
　　We usedpictures, because your brain is tuned for visuals, not text. As far as your brain's concerned, a picture really is worth a thousand words. And when text and pictures work together, we embedded the text in the pictures because your brain works more effectively when the text is within the thing the text refers to, as opposed to in a caption or buried in the text somewhere.
　　We used redundancy, saying the same thing in different ways and with different media types,and multiple senses, to increase the chance that the content gets coded into more than one area of your brain.
　　We used concepts and pictures in unexpected ways because your brain is tuned for novelty,and we used pictures and ideas with at least some emotional content, because your brain is tuned to pay attention to the biochemistry of emotions. That which causes you to feel something is more likely to be remembered, even if that feeling is nothing more than a little humor, surprise, or interest.
　　We used a personalized, conversational style, because your brain is tuned to pay more attention when it believes you're in a conversation than if it thinks you're passively listening to a presentation. Your brain does this even when you're reading.
　　We included more than 80 activities, because your brain is tuned to learn and remember more when you do things than when you read about things. And we made the exercises challenging-yet-do-able, because that's what most people prefer.
　　We used multiple learning styles, becauseyou might prefer step-by-step procedures, while someone else wants to understand the big picture first, and someone else just wants to see an example. But regardless of your own learning preference, everyone benefits from seeing the same content represented in multiple ways.
　　We include content for both sides of your brain, because the more of your brain you engage, the more likely you are to learn and remember, and the longer you can stay focused.Since working one side of the brain often means giving the other side a chance to rest, you can be more productive at learning for a longer period of time.
　　And we included stories and exercises that present more than one point of view, because your brain is tuned to learn more deeply when it's forced to make evaluations and judgments.
　　We included challenges, with exercises, and by asking questions that don't always have a straight answer, because your brain is tuned to learn and remember when it has to work at something. Think about it-you can't get your body in shape just by watching people at the gym. But we did our best to make sure that when you're working hard, it's on the right things.That you're not spending one extra dendrite processing a hard-to-understand example, or parsing difficult, jargon-laden, or overly terse text.
　　We used people. In stories, examples, pictures, etc., because, well, because you're a person. And your brain pays more attention to people than it does to things.