18 May, 2010

愚而好自用

2010年5月18日

信報研究部

破除成見提高投資致勝率

子曰:愚而好自用;近代英國哲學、邏輯及數學通才羅素(Bertrand Russell)說:今時今日是愚人自信心十足而智者充滿疑惑的世界(In the modern world the stupid are cocksure while the intelligent are full of doubt)。愚人不但固執,有人更會堅持一些匪夷所思的成見,美國兩位學者研究發現心理學上的「後設認知」(metacognitive)能力問題可以解釋愚好自用的部分原因。

1995年某一天,美國Pittsburgh的McArthur Wheeler光天化日施施然走進兩間銀行持槍行劫,由於Wheeler完全沒有掩人耳目的化裝,他的廬山真面在早上11時的電視新聞報道播出後,警方根據線報當晚已緝捕Wheeler歸案。Wheeler在警局看到攝錄機播放他行劫的影片時大惑不解地喃喃自語:「我明明已經搽了檸檬汁的。」原來Wheeler不知聽了哪個紅鬚軍師的指點,以為用檸檬汁塗面在攝錄機鏡頭下是隱形的。

心理學上的過度自信(overconfidence)和後設認知(metacognitive)都會使人高估自己的能力,尤其是後設認知更會影響個人反省本身「知識」的謬誤。後設認知理論是由John Flavell所創,主要內容可分為後設認知知識(metacognitive knowledge)和後設認知經驗,後設認知知識是指個人在認知過程所獲得知識(acquired knowledge)的認知,並且指導自己如何使用(可能是錯誤的)知識與策略,Wheeler明顯是受到後設認知所誤。

後設認知不足與過度自我評價(inflated self-assessment)有直接關係,美國紐約大學的Justin Kruger和康乃爾大學(Cornell University)的David Dunning兩位心理學教授2009年12月發表了一份相關議題的詳盡研究報告(K&D)。K&D設計四個實驗,根據參與實驗的康乃爾學生對幽默感、邏輯推理和英文文法的認識和自我評估,分析人們缺乏自知之明反而更加自信的現象。

校準誤差

K&D前設預期是能力不足者(incompetent)會自覺表現勝過同儕,而且欠缺洞察力,未能透過觀察他人的長處來自我提升。參加第一項實驗的是65位學生,K&D搜羅了30則笑話,叫學生由1(完全不好笑)至11(非常好笑)給予每則笑話的好笑程度評分,在這之前,K&D先將該30則笑話邀請7位喜劇演員評分,以專業者的意見對照學生在幽默感方面的認知。K&D認為,透過這個實驗,可以探測參加者是否具有察知他人內心感受的能力和知識。最後,K&D要求參加者與所有學生的評級(0至100)比較,再由0(自認最低層級,bottom quartile)至50(剛好一般水平)至99(自認最高層級)評估自己對幽默感的感知能力(perceived ability)。K&D從實驗發現,雖然個人自覺能力在一定程度上反映其實際能力,但人們往往自感本身能力勝過同儕,更重要的是,表現特別差劣的部分參加者完全不察覺本身能力不足的事實,得分最低層的參加者甚至以為自己的成績比實際高46%【圖1】。

第二個實驗是測試參加者的邏輯推理能力,K&D懷疑邏輯推理能力測驗成績差勁的是否知道自己技不如人。幽默感還可以爭論是見仁見智,法理邏輯的對與錯是鐵板一塊的硬道理。參與實驗的45位學生要回答法學院入學試抽出的20條試題,然後K&D詢問學生自己估計答對了多少題,再將參加者的自我評估分數及對邏輯推理的認知能力,和他們的實際得分比較,以檢驗參加者的校準誤差(miscalibration)。測驗結果再一次證實,得分最低層的參加者也是高估自己的成績【圖2】,並深信本身實力必定在及格水平以上,他們自信正確解答14.2條試題,而真正成績只得9.6;反而得分最高層級的參加者卻自覺只答中14題,但他們其實取得高達16.9的佳績。

K&D設計的第三項實驗分為兩個階段,都是有關英文文法的測試。K&D查詢參加實驗的84位學生對美國標準書面英語(American Standard Written English)的認識,並要求學生回答20條來自全國教師考試(National Teacher Examination)的文法試題,每題其中一條劃有底線的句子,參加者要判斷句子的文法是否錯誤。最後,參加者須自我評估有關正確英文文法的認知、測驗得分和與其他學生比較。【圖3】顯示,參加者的自我評估和實際得分再次出現巨大落差。測試後4至6個星期,K&D邀請測試得分最底和最高層級的學生參加第二階段的實驗,學生回到實驗室後,K&D分派給參加者5份第一階段其他學生的試卷,然後叫參加者根據他們認為試卷正確答案的數目給予評級,K&D的目的是要觀察參加者是否可以從他人的成績提高自我的後設認知能力。結果一如K&D預期,能力不足者並沒有從其他同學的正確答案反省本身的錯誤,依然自我感覺勝同儕。


過猶不及

經過三輪實驗,除了證實能力不足者的表現符合前設預期外,K&D並發現得分最高層級的參加者也一致出現校準誤差的問題,他們都低估自己的能力【圖1,2,3】。K&D分析,由於他們每次測試表現良好,也會推算其他同學都同樣有好表現,反而不敢太高估自己的成績,在心理學上名為錯誤等同(false-consensus)現象。

K&D將缺乏知識或智慧以至表現欠佳的普遍案例歸因於後設認知能力的不足,缺少後設認知能力不但令人看不到自己的弱點而經常作出錯誤選擇,而且自以為是漠視他人的優點,不會「擇其善者而從之」去提升自己的學識,正如實驗研究證明個別能力不足者都拒絕觀摩他人的長處,得分最低層級者即使讓他們看到其同學高手的成績,他們仍堅持自己是對的;至於得分最高層級的參加者則不會受其他同學錯誤答案影響本身的信心,反而會將他人的錯失引以為誡,「其不善者而改之」,並由此改進自我評估的校準誤差。

K&D最後一項測試希望證明通過訓練是否有效提高個人的後設認知能力。140位學生先進行P.C. Wason設計的撲克牌推理測驗,並照樣自我評估測試表現。然後,所有學生都進行一個10分鐘的培訓課程,K&D派給每人關於Wason實驗的邏輯推理「錦囊」,但其中半數學生收到的是與測驗無關的邏輯資料。10分鐘後,參加者重新對測驗成績再作一次自我評估。K&D發現,參加者受訓前的自我評估與頭三次測驗結果大同小異,得分最低層級學生同樣高估自己的表現【圖4】,但經過訓練卻達到K&D的預期效果:能力不足者多了認知自己哪條問題是答對還是答錯,從而減少自我感覺(self-impression)的校準失誤。

得分最低層級的參加者四項實驗都一致認為本身能力高於常人的「自我感覺良好」心態,最低限度證明了英國詩人Thomas Gray(1716-1771)是對的:無知是福,自我滿足(Ignorance is bliss at least when it comes to assessments of one's own ability)。

K&D的實驗對投資者的啓發是在這個資訊爆炸的世紀,參考有用正確的資訊(第四個實驗的錦囊),會有助提高個人的知識也就是後設認知能力,破除成見減少投資失誤;K&D證實人們普遍認為自己能力高於一般人水平,但每每由於自我評估與現實有偏差以致投資失誤,例如2008年滙控股價跌破100元的時候,不少投資者都確信其股價已低於內在價值而買入,其實有多少投資者有能力及足夠資料去計算滙控或者其他股票的內在價值?

策劃 信報研究部

撰文 徐天任

21 July, 2009

RiSA #4: 3D FPS - The Legend

It has nothing to do with the famous novel or the tie-in movie. And from the screen shot, it is striking familiar to a very famous shooting game. And your guess is right: it is a total rip-off:

http://appshopper.com/games/3d-fps-the-legend

I don't know how Apple manages to let this thing gets through the review process in the first place!

19 June, 2009

Obama's Speech on Falther's Day (2008)

Good morning. It's good to be home on this Father's Day with my girls, and it's an honor to spend some time with all of you today in the house of our Lord.

At the end of the Sermon on the Mount, Jesus closes by saying, “Whoever hears these words of mine, and does them, shall be likened to a wise man who built his house upon a rock: and the rain descended, and the floods came, and the winds blew, and beat upon that house, and it fell not, for it was founded upon a rock.” [Matthew 7: 24-25]

Here at Apostolic, you are blessed to worship in a house that has been founded on the rock of Jesus Christ, our Lord and Savior. But it is also built on another rock, another foundation -- and that rock is Bishop Arthur Brazier. In forty-eight years, he has built this congregation from just a few hundred to more than 20,000 strong -- a congregation that, because of his leadership, has braved the fierce winds and heavy rains of violence and poverty; joblessness and hopelessness. Because of his work and his ministry, there are more graduates and fewer gang members in the neighborhoods surrounding this church. There are more homes and fewer homeless. There is more community and less chaos because Bishop Brazier continued the march for justice that he began by Dr. King’s side all those years ago. He is the reason this house has stood tall for half a century. And on this Father’s Day, it must make him proud to know that the man now charged with keeping its foundation strong is his son and your new pastor, Reverend Byron Brazier.

Of all the rocks upon which we build our lives, we are reminded today that family is the most important. And we are called to recognize and honor how critical every father is to that foundation. They are teachers and coaches. They are mentors and role models. They are examples of success and the men who constantly push us toward it.

But if we are honest with ourselves, we’ll admit that what too many fathers also are is missing -- missing from too many lives and too many homes. They have abandoned their responsibilities, acting like boys instead of men. And the foundations of our families are weaker because of it.

You and I know how true this is in the African-American community. We know that more than half of all black children live in single-parent households, a number that has doubled -- doubled -- since we were children. We know the statistics -- that children who grow up without a father are five times more likely to live in poverty and commit crime; nine times more likely to drop out of schools and twenty times more likely to end up in prison. They are more likely to have behavioral problems, or run away from home, or become teenage parents themselves. And the foundations of our community are weaker because of it.

How many times in the last year has this city lost a child at the hands of another child? How many times have our hearts stopped in the middle of the night with the sound of a gunshot or a siren? How many teenagers have we seen hanging around on street corners when they should be sitting in a classroom? How many are sitting in prison when they should be working, or at least looking for a job? How many in this generation are we willing to lose to poverty or violence or addiction? How many?

Yes, we need more cops on the street. Yes, we need fewer guns in the hands of people who shouldn’t have them. Yes, we need more money for our schools, and more outstanding teachers in the classroom, and more after-school programs for our children. Yes, we need more jobs and more job training and more opportunity in our communities.

But we also need families to raise our children. We need fathers to realize that responsibility does not end at conception. We need them to realize that what makes you a man is not the ability to have a child -- it’s the courage to raise one.

We need to help all the mothers out there who are raising these kids by themselves; the mothers who drop them off at school, go to work, pick them up in the afternoon, work another shift, get dinner, make lunches, pay the bills, fix the house, and all the other things it takes both parents to do. So many of these women are doing a heroic job, but they need support. They need another parent. Their children need another parent. That’s what keeps their foundation strong. It’s what keeps the foundation of our country strong.

I know what it means to have an absent father, although my circumstances weren’t as tough as they are for many young people today. Even though my father left us when I was two years old, and I only knew him from the letters he wrote and the stories that my family told, I was luckier than most. I grew up in Hawaii, and had two wonderful grandparents from Kansas who poured everything they had into helping my mother raise my sister and me -- who worked with her to teach us about love and respect and the obligations we have to one another. I screwed up more often than I should’ve, but I got plenty of second chances. And even though we didn’t have a lot of money, scholarships gave me the opportunity to go to some of the best schools in the country. A lot of kids don’t get these chances today. There is no margin for error in their lives. So my own story is different in that way.

Still, I know the toll that being a single parent took on my mother -- how she struggled at times to the pay bills; to give us the things that other kids had; to play all the roles that both parents are supposed to play. And I know the toll it took on me. So I resolved many years ago that it was my obligation to break the cycle -- that if I could be anything in life, I would be a good father to my girls; that if I could give them anything, I would give them that rock -- that foundation -- on which to build their lives. And that would be the greatest gift I could offer.

I say this knowing that I have been an imperfect father -- knowing that I have made mistakes and will continue to make more; wishing that I could be home for my girls and my wife more than I am right now. I say this knowing all of these things because even as we are imperfect, even as we face difficult circumstances, there are still certain lessons we must strive to live and learn as fathers -- whether we are black or white; rich or poor; from the South Side or the wealthiest suburb.

The first is setting an example of excellence for our children -- because if we want to set high expectations for them, we’ve got to set high expectations for ourselves. It’s great if you have a job; it’s even better if you have a college degree. It’s a wonderful thing if you are married and living in a home with your children, but don’t just sit in the house and watch “SportsCenter” all weekend long. That’s why so many children are growing up in front of the television. As fathers and parents, we’ve got to spend more time with them, and help them with their homework, and replace the video game or the remote control with a book once in awhile. That’s how we build that foundation.

We know that education is everything to our children’s future. We know that they will no longer just compete for good jobs with children from Indiana, but children from India and China and all over the world. We know the work and the studying and the level of education that requires.

You know, sometimes I’ll go to an eighth-grade graduation and there’s all that pomp and circumstance and gowns and flowers. And I think to myself, it’s just eighth grade. To really compete, they need to graduate high school, and then they need to graduate college, and they probably need a graduate degree too. An eighth-grade education doesn’t cut it today. Let’s give them a handshake and tell them to get their butts back in the library!

It’s up to us -- as fathers and parents -- to instill this ethic of excellence in our children. It’s up to us to say to our daughters, don’t ever let images on TV tell you what you are worth, because I expect you to dream without limit and reach for those goals. It’s up to us to tell our sons, those songs on the radio may glorify violence, but in my house we live glory to achievement, self respect, and hard work. It’s up to us to set these high expectations. And that means meeting those expectations ourselves. That means setting examples of excellence in our own lives.

The second thing we need to do as fathers is pass along the value of empathy to our children. Not sympathy, but empathy -- the ability to stand in somebody else’s shoes; to look at the world through their eyes. Sometimes it’s so easy to get caught up in “us,” that we forget about our obligations to one another. There’s a culture in our society that says remembering these obligations is somehow soft -- that we can’t show weakness, and so therefore we can’t show kindness.

But our young boys and girls see that. They see when you are ignoring or mistreating your wife. They see when you are inconsiderate at home; or when you are distant; or when you are thinking only of yourself. And so it’s no surprise when we see that behavior in our schools or on our streets. That’s why we pass on the values of empathy and kindness to our children by living them. We need to show our kids that you’re not strong by putting other people down -- you’re strong by lifting them up. That’s our responsibility as fathers.

And by the way -- it’s a responsibility that also extends to Washington. Because if fathers are doing their part; if they’re taking our responsibilities seriously to be there for their children, and set high expectations for them, and instill in them a sense of excellence and empathy, then our government should meet them halfway.

We should be making it easier for fathers who make responsible choices and harder for those who avoid them. We should get rid of the financial penalties we impose on married couples right now, and start making sure that every dime of child support goes directly to helping children instead of some bureaucrat. We should reward fathers who pay that child support with job training and job opportunities and a larger Earned Income Tax Credit that can help them pay the bills. We should expand programs where registered nurses visit expectant and new mothers and help them learn how to care for themselves before the baby is born and what to do after -- programs that have helped increase father involvement, women’s employment, and children’s readiness for school. We should help these new families care for their children by expanding maternity and paternity leave, and we should guarantee every worker more paid sick leave so they can stay home to take care of their child without losing their income.

We should take all of these steps to build a strong foundation for our children. But we should also know that even if we do; even if we meet our obligations as fathers and parents; even if Washington does its part too, we will still face difficult challenges in our lives. There will still be days of struggle and heartache. The rains will still come and the winds will still blow.

And that is why the final lesson we must learn as fathers is also the greatest gift we can pass on to our children -- and that is the gift of hope.

I’m not talking about an idle hope that’s little more than blind optimism or willful ignorance of the problems we face. I’m talking about hope as that spirit inside us that insists, despite all evidence to the contrary, that something better is waiting for us if we’re willing to work for it and fight for it. If we are willing to believe.

I was answering questions at a town hall meeting in Wisconsin the other day and a young man raised his hand, and I figured he’d ask about college tuition or energy or maybe the war in Iraq. But instead he looked at me very seriously and he asked, “What does life mean to you?”

Now, I have to admit that I wasn’t quite prepared for that one. I think I stammered for a little bit, but then I stopped and gave it some thought, and I said this:

When I was a young man, I thought life was all about me -- how do I make my way in the world, and how do I become successful and how do I get the things that I want.

But now, my life revolves around my two little girls. And what I think about is what kind of world I’m leaving them. Are they living in a county where there’s a huge gap between a few who are wealthy and a whole bunch of people who are struggling every day? Are they living in a county that is still divided by race? A country where, because they’re girls, they don’t have as much opportunity as boys do? Are they living in a country where we are hated around the world because we don’t cooperate effectively with other nations? Are they living in a world that is in grave danger because of what we’ve done to its climate?

And what I’ve realized is that life doesn’t count for much unless you’re willing to do your small part to leave our children -- all of our children -- a better world. Even if it’s difficult. Even if the work seems great. Even if we don’t get very far in our lifetime.

That is our ultimate responsibility as fathers and parents. We try. We hope. We do what we can to build our house upon the sturdiest rock. And when the winds come, and the rains fall, and they beat upon that house, we keep faith that our Father will be there to guide us, and watch over us, and protect us, and lead His children through the darkest of storms into light of a better day. That is my prayer for all of us on this Father’s Day, and that is my hope for this country in the years ahead. May God Bless you and your children. Thank you.

Homemade wheel for iPhone / iPod Touch

(FYI: all photos and videos can be found here)

Well, instead of sending out "instructions" individually, I am spilling the whole nine yards here. This "device" is open-sourced (against my wife's wish, cause I tell her anyone can do it), so in case anyone wants to mass-produced this (really?), please make sure you give me a credit along.

Parts

1 Wii racing wheel with stand. I like the version I get which has no extra cables and buttons, but with a "slot" to allow the USB cable to pass through (for prolong "potato-couching" my wife notes). Also, you can unlock the axis so that you can use it for bi-axis games too.

2. A iPhone or iPod Touch back cover. Plastic with no imprint and emboss is the best, I think. The choice of colour is a matter of taste.

Preparation

For the back cover, trim the curved edge for easy mounting and dismounting. Too much trim may cause your device to fall out when you are hot in "action", so for me, I trip the "camera hole" edge just covers the half-way of my device. This also makes it possible to mount it with the Home on the left for games like Galaxy on Fire (who care about the camera anyway).

You can refer to the photos on the cuttings made.

Another reason to trip one side of the cover, most covers I find are very hard to dismount, so if I leave it as is, it could cause great tear and stress between the connecting surfaces between the cover and the wheel.

There is nothing to work on further on the wheel itself -- you may wish to put some counter weight (lead for fishing?) on the other end of the wheel cause when mounted, the wheel has a tendency of leaning on to you.

Mounting

The most important point, perhaps, is to mount your device as balance as possible so it will not hinder your gaming experience. Both the plate and the wheel must align horizontally together, also the device 's CoG must be neutral so that no tilting when the device is at rest.

I mount the back cover onto the outside of the Wii controller stopper. It sounds very natural to me as it is the center of the wheel and it is the only place with the largest surface area to hold the cover. If you have got different models of wheel, you may need to find another spot which works best for you.

So before gluing up, mount the back onto your device with USB cable on, and possibly the headphone, and find the best position. Once that location is found, make marks. Apply strong glue onto the wheel where you would mount on cover on. Once fixed, press the cover a little, wait for the glue to dry (that is the hardest part), and start enjoying.

I guess there are still rooms for improvement but so far, I am enjoying it.

Any questions and comments are welcomed.

05 June, 2009

Sketch Dungeon Impressions

Played it from start in the washroom and wrap up at level 8. Here are some impressions for your references:

1. I would say this is a shooter running on a "sketch style" background. The graphics are nice, simple and pretty consistent in style.

2. The ability of zooming in and out of the map is good, but most of the time, you would prefer zooming all out most of the time to check those corners.

3. The sound and music are okay, but I would wish there were volume controls. Movements is done by accelerometer, the sensitivity is okay but cannot be adjusted. The calibration is very simple and it works.

4. The game play is simple, run through the maze to reach the stairs for another level. In due course, there are different types of enemies standing in your way.

5. Your weapon against the monster would be a crossbow with unlimited ammo and unlimited. Later in game, you can find other better crossbow for use. You shoot by tap and at the direction to shoot. If you hold the tap, you strafe.

6. Due to the nature of this arrangement, one of the best, but gamey you can say, is to "shoot first, question later". Most of the time, you would hear something die in screaming down the corridor without seeing a face...

7. The PC has no statistics other than the "HP" remaining. If the HP reaches zero, the PC dies. There are statistics of how many gold are collected and how many kills but so far, I cannot see anything which helps with the gameplay.

The maze is littered with items, boxes or barrels of gold (some have other surprises), keys to various doors of the level, which disappear when you move to the next level, HP aid, in form of chicken.

Bottom line: Simple and stylish shooter and some extend, maze clawer. If you expect something like Rogue you would be disappointed but so far, I find it quite enjoyable.

04 June, 2009

iBomber Comments

Menu:
Simple and yet adequate.

Sound:
Music is okay, add some atmosphere, but it gets repetitive very quickly. The AA sound is just bare and too simple to my taste. Some flak sound chould leave a better impression of "being there" but it is missing. Also, I find no buzz noise of bomb falling is very disappointing.

Graphics:
Adequate, not too 3D-ish like you find like AC-130. The UI layout provides all the information the player needs without obscuring the play area. However(!), some ground targets, especially the pillboxes at the bridge level, shows no visual change after being damaged.

Control:
The use of acclereometer for piloting and speed control is fine. The bad: too many a time clicking power-ups also hits the menu button. Worse you get no sound effect when you have picked up a power up, which means slight distraction to see if the power-up desperately needed has been in-store.

Moreover, the bomb reticle is not useful for most of the time and it does not change according to bomb type you are carrying. I am not asking for a Norden but there should be something to make things a bit more comfortable.

Bombs (worth special mention):
There is an unlimited supply of regular bomb and you can pick up different types of others after hitting a target. They show up randomly and the number of these special bombs you get varies with the mission you are at, except for the big bad yellow, which is always a single-shot.

Rocket bomb is the "precision" bomb of choice, same damage as the default and drops straight down. However, it is of the same speed as the other free falling bomb, strange, very strange.

Red bomb is some kind of "cluster bomb" which consists of three bombs, all with the same damage levels. The two of which spread to the front left and right of the "aim point". Not good for naval and areal enemies and works best against concentrated ground targets.

Yellow bomb is the "nuke-wannabe", it is the biggest and the baddest thing in your arsenal. However, for some reason unknown, it actually falls slower than all other bombs, making it very hard to use. Another notable thing is, if you manage to land this bada** onto land zone, the blast can damage, not only the land targets, also any ships happen to stay too close. If it lands on water, well, nothing happens (except for an extraordinary big splash). Trust me, in case this hits something "solid", mayhem ensures. I have yet to see a ship which can withstand a direct hit by it.

Game play:

A slight variation of rail shooter which you can actually navigate in a very tight game area dotted with targets. You are thrown straight into the hot zone (or target-rich area if you prefer). Since the bomb sight serves nothing but to show you where the middle of the screen is, tapping non-stop on the "bombs away" button is almost a norm.

Each stage has one or more "objectives" and the mission will abruptly ends when you satisfiy all the objectives required. So if you aim to collect medals (see below), watch your pace and some time it is not as easy as you think.

(How can I forget this?!) If you beat the mission but careless enough to choose to "retry", and you are stuck with that mission and if you quit, you cannot proceed to the next one. Possible design fault?

There are 4 sets of medals. If you can wipe out over 90% of buildings, you get a medal, ships (including planes!), you get another medal and if you gain 90% or better accuracy, you get another medal for that.

There are twelve "missions" overall which vary between "bombing everything up" or "protecting your guys by bombing everything else up". Not boring since if you are in a mood of blowing, it is actually fun. However, the hardness of the mission is not quite going in one direction. Say, I have beaten a quite hard mission is protecting my guys against naval onslaught (odd enough, the enemy manages to place nests of AAA within my force's shooting distance), the next mission is a joy ride of cleansing the map.

Baseline:
Fun and enjoyable for those who want to simply blow things up, not much replay value other than challenging yourself or entertain the wish of more blowing-ups. With the avant of so many games flooding in the Store right now, there is little or no incentive to return to it after beating.

(I am not giving any ranks to avoid the illusion of comparing apples with oranges).

13 May, 2009

How NOT to promote your game in iTunes Store #4

Describe your game as "addictive" without realising that all real addictive stuff charges much more than your price level...