Or a mathematician.

Lately I've been extraordinarily surprised at how effective potassium and potassium salt are. By which I mean that simple potassium is probably the most positively mind altering supplement I've ever tried.

It would be an error to suppose that the great discoverer seizes at once upon the truth, or has any unerring method of divining it. In all probability the errors of the great mind exceed in number those of the less vigorous one. Fertility of imagination and abundance of guesses at truth are among the first requisites of discovery; but the erroneous guesses must be many times as numerous as those that prove well founded. The weakest analogies, the most whimsical notions, the most apparently absurd theories, may pass through the teeming brain, and no record remain of more than the hundredth part….

W. Stanley Jevons

Although this may seem a paradox, all exact science is dominated by the idea of approximation. When a man tells you that he knows the exact truth about anything, you are safe in inferring that he is an inexact man.

Bertrand Russell

The important thing in science is not so much to obtain new facts as to discover new ways of thinking about them.

William Lawrence Bragg

The most valuable acquisitions in a scientific or technical education are the general-purpose mental tools which remain serviceable for a lifetime. I rate natural language and mathematics as the most important of these tools, and computer science as a third.

George E. Forsythe

Every chess player has to memorize opening theory or they can't make progress. I agree that this is often over-emphasized, generally because it's the easiest thing for a coach to assign. I do think opening theory is pretty fundamental because it is a constructive way to teach someone about controlling the center of the board and developing pieces, which need to be learned concurrently with tactics. The same errors that people fall into with over-emphasizing openings are also prone to occur when people over-emphasize solving chess puzzles or replaying GM games. If you spend too much time on any one aspect in the developmental stage, it's not good. But still, 1200 level players must really study a few basic openings just to even get a handle on engaging in a game of chess.

My preferred approach is to teach one or two main variations for a couple of openings for both black and white. Then, after these are reasonably understood, I like to spend time focusing on the goals of the opening, like controlling the center of the board and developing minor pieces to good posts. That's usually the point where tactics and combinations start to become relevant, so its natural to work on that. This is just my opinion, of course. I'm sure many chess instructors have their own opinions.

Playing slow chess is by far the most problematic issue. Chess requires so much patience, and thinking like a computer when your opponent is thinking about their own move is really hard, especially for children. Most kids don't have many options to practice other than internet chess, which is generally blitz dominated.

At any rate, I never believe that memorizing opening theory is an important goal unto itself, not even at the highest level. It goes in spurts. Maybe study the Ruy Lopez and Queen's Gambit to illustrate basic ideas about central control, then take a break from openings and play dozens of Ruy Lopez or Queen's Gambit games to build up the ability to systematically study positions and compute moves, then go back and extend some opening knowledge to study piece development, then play more games and study tactics and combinations.

My only point in my original comment was that because of the systematic approach to move calculation and focus of attention, top chess players are usually not concerned about distraction so much. It is exactly avoidance of distraction that they have been training for to get them into the big tournament games in the first place.

I've played in several competitive tournaments myself and had a chess coach for a number of years. I don't know of any general studies or research (so I'll be interested if anyone finds anything more principled than my anecdotal evidence). In my experience, the main goal of chess coaching and training was to teach you how to act like you were a computer. Any kind of "intuitive" play or even creative play was harshly criticized from a young age. The first goal was to memorize a massive amount of opening theory and what is known as 'book' knowledge. Once a student has a reasonable amount of book knowledge, then you move on to techniques to focus you on calculating quickly.

In my later years, I've come to realize that the heuristics that chess teachers employ cause you to think in a way that's analogous to simulated annealing. You scan the board and make simulated "proposal" moves in your head, and in the early stages of your turn you should be very open (high temperature) to suggesting any move, no matter how preposterous, to yourself. But you also have to just very quickly look at the move's surface level consequences and basically classify it as "worth more of a look" or "worthless". You do this a few times, and assuming some independence of the distribution of your brain's ability to pick out decent moves, you'll have whittled down to maybe 5-10 respectable moves, and perhaps a few other riskier moves worth a second look.

At this point you really dive in deep and attempt to examine long chains of moves, maybe 5-6 moves deep for each of the 5-10 moves you've got going in your head. Your annealing temperature is much lower, so you're less likely to spend time thinking about weird variants or moves that don't have an obvious upside. You systematically focus on understanding two things, the immediate consequences of the moves and the level of complication each line of hypothetical play will bring about. The reason complication matters is that human chess is all about resource management. Given enough time, every player in the tournament is good enough to see the best moves, potentially even the best moves that a computer would see. The difference in human performance, though, is decision fatigue, carelessness, and inability to calculate long, complicated lines in memory (some kind of human cache limit, basically).

During this deeper analysis stage, you should ultimately come down to 3 moves that seem to be the best. For these moves, you'll go back over the 5-10 move sequences, maybe even up to 15 moves deep if you're a grandmaster, and you'll not only detect the complication, but also the larger strategic principles. Will having two bishops in this particular variation give you more mobility? Will your pawn structure effectively lock down your pieces? After the dust settles in a large exchange sequence, will your opponent have a passed pawn and can you stop it without losing a whole piece to babysit that pawn? Will there be pressure on the dark (or light) squares because of an exploitable tactic. From this, you eventually emerge with your chosen move.

There is also some meta-analysis that goes into it. Since you are analyzing the amount of complications expected in certain lines of play, you also develop some experience for knowing when the really critical points of the game are happening. You obviously cannot spend the effort of the paragraphs above on every single move. You have to miniaturize it and hurry it up for most moves, and to do that safely you need to be confident that you're not making fast moves in a deeply complicated portion of the game. This can be accomplished by studying lots of classical games, or by knowing a lot about your opponent's games and styles prior to a match, Most grandmasters will have only two or three moves per game that take longer than 15 minutes to make, but each of these will take 45+ minutes. If you spend 45 minutes on a move, you have to get more bang for your buck out of that move, so the subsequent moves should be able to go faster. If you spent 45 minutes on a move and then your opponent surprises you and you have to spend another large chunk of time, you're in trouble.

At any rate, my experience was that the nerves and the situation don't play much of a role at all because, if you have practiced well enough, you dive right into this deep Zen of computation, busily reducing the game down into the conscious simulation of a serial algorithm plus memory lookups, according to what your coach / training has taught you.

A good way of getting cheap textbooks is to use a price alert service that notifies you when the price of a new or used book drops below a certain price. When you don't need the text in a hurry, and would rather save money and buy used, that works well, because students often want to get rid of a textbook in a hurry and offer it for sale at far below the typical used price for that book. Those deals tend to go pretty quickly though.

Another good idea is to buy the previous edition, especially for texts that have many editions. When the 8th edition of a textbook is going for $80 used, you can often get the 7th edition used for ridiculously cheap (like $10 or $15), and the previous edition was often released just a few years ago (some texts have a new edition every few years) and has only minor differences.

I think the positive reactions are probably mostly a case of guessing the teacher's password. Perhaps the teacher conveyed a positive impression beforehand, but the default password guessing behavior would probably be to guess "teacher wants us to write about this appreciatively" regardless of whether he said anything additional about the site -- that would be expected for a community blog devoted to refining the art of {rationality, wisdom, justice, aesthetics, ...}.