Bayesian Recognition

We don’t meet often, but every time we talk, she reminds me that I had failed to recognize her the first time we had met after graduating together from school. Yes, I could claim in my defence that I was seeing her for the first time in over six years. While that might be a valid excuse for most people, it doesn’t apply to me, since I normally claim to have superior long-term memory. If I’ve seen you somewhere before, I ought to recognize you. The only times I don’t I’m pretending, since I don’t want to embarrass you (and myself) by recognizing you while you don’t recognize me (see this incident for an example of this).

The reason for my failure that cold Bangalore evening in December 2006 was that my Bayesian system had failed me. Let me explain, in the process giving you an insight into my Bayesian system which I use to recognize you when I meet you.

About a month or two back, I was at a friend’s wedding, which is where I hit upon this term “Bayesian recognition” to explain this phenomenon ¬†(which I’ve been practicing for ages). Now, this friend whose wedding I was attending was one year my junior at two different schools. As you might expect at an event where you and the host share more than one social network, there were a lot of familiar faces. Some people I knew fairly well, and could easily recognize. But the others had to go through a “Bayesian search”.

So when I saw someone who was one of three people I know – let’s say X, Y and Z. In order to determine which of these this person is, I would ask myself two questions – firstly, what were the prior odds that the person I saw could be each of X, Y or Z. Secondly, what were the odds of each of X, Y and Z being there at that event. Note that the latter is important. For example, if someone at the event looks like you and I know (for example) that you are currently in another country, despite the strong resemblance I can discount the possibility that that person is you, and go ahead with my search.

Note that this differs from “frequentist recognition”, where I only look at the person’s face and try and understand who he/she most resembles, without any thought to the odds that that person is there. Frequentist recognition can lead to a large number of false positives, and after a few rounds of embarrassment, you start giving up on recognizing, and many a possible reunion thus gets missed. Bayesian recognition, on the other hand, restricts your field of search (to the people who you give good odds of being there), prevents you from being distracted and increases your chances of making a good recognition.

So why did Bayesian recognition fail me when I met this former classmate back in 2006? The problem was her company. She had come for this Deep Purple concert with another friend of mine, who was my classmate in another school (and who I had been in touch with, and so easily recognized). I had no clue that these two were friends (it turned out they didn’t know each other that well – they had come there with a common friend). So when this girl (the one I didn’t recognize) popped up with “Hey SK! Do you remember me?” I assumed that she was someone I knew from the same school as the other girl I was meeting, and that wrongly restricted my search space. And so my mind was trying to map her to my friends from school 1, while she happened to be a friend from school 2. And my search returned a blank, and my legendary long-term memory skills were embarrassed.

I must mention here, though, that this is possibly the only time that my Bayesian recognition model has acted up, and refused to recognize someone I know. There have been 2-3 false positives, but this has been the only negative. And when you consider the sample size to be all the people I have recognized in different places, this is small indeed.

Oh, and after failing to recognize her then, I’ve kept in touch with this friend.

The day I learnt to stop worrying and learnt to protect myself

For at least six years, from early 2006 to early 2012 I “suffered” from what medical practitioners term as “anxiety”. It was “co-morbid” with my depression, and I think it was there from much before 2006. I would frequently think about random events, and and wonder what would happen if things happened in a certain way. I would think of “negative black swan” events, events with low probability but which would have a significant negative impact on my life.

While considering various possibilities and preparing for them is a good thing, the way I handled them were anything but good. Somewhere in my system was wired the thought that simply worrying about an event would prevent it from happening. I once got fired from one job. Every day during my next two jobs, I would worry if I would get fired. If I got an uncharitable email from my boss, I would worry if he would fire me. If my blackberry failed to sync one morning I would worry that it was because I had already been fired. Needless to say, I got fired from both these jobs also, for varying reasons.

I used to be a risk-taker. And it so happened that for a prolonged period in my life, a lot of risks paid off. And then for another rather prolonged period, none of them did (Mandelbrot beautifully calls this phenomenon the Joseph effect). The initial period of successful risk-taking probably led me to take more risk than was prudent. The latter period of failure led me to cut down on risks to an unsustainable level. I would be paranoid about any risks I had left myself exposed to. This however doesn’t mean that the risks didn’t materialize.

It was in January of last year that I started medication for my anxiety and depression. For a few days there was no effect. Then, suddenly I seemed to hit a point of inflexion and my anxious days were far behind. While I do credit Venlafaxine Hexachloride I think one event in this period did more than anything else to get me out of my anxiety.

I was riding my Royal Enfield Classic 500 across the country roads of Rajasthan, as part of the Royal Enfield Tour of Rajasthan. The first five days of the tour had gone rather well. Riding across the rather well-made Pradhan Mantri Gram Sadak Yojana (PMGSY) roads set across beautiful landscapes had already helped clear out my mind a fair bit. It gave me the time and space to think without getting distracted. I would make up stories as I rode, and at the end of each day I would write a 500 word essay in my diary. All the riding gear meant that the wind never really got into my hair or my face, but the experience was stunning nevertheless. For a long time in life, I wanted to “be accelerated”. Ride at well-at-a-faster-rate, pulling no stops. And so I rode. On the way to Jaisalmer on a rather empty highway, I even hit 120 kmph, which I had never imagined I would hit on my bike. And I rode fearlessly, the acceleration meaning that my mind didn’t have much space for negative thoughts. Things were already so much better. Until I hit a cow.

Sometimes I rationalize saying I hadn’t consumed my daily quota of Venlafaxine Hexachloride that morning. Sometimes I rationalize that I was doing three things at the same time – one more than the number of activities I can normally successfully carry out simultaneously. There are times when I replay the scene in my head and wonder how things would have been had I done things differently. And I sometimes wonder why the first time I ever suffered a fracture had to happen in the middle of nowhere far off from home.

It had been a wonderful morning. We had left the camp at Sam early, stopping for fuel at Jaisalmer, and then at this wonderful dhaba at Devikot, where we had the most awesome samosa-bajjis (massive chilis were first coated with a layer of potato curry – the one they put in samosa – and then in batter and deep fried). For the first time that day I had the camera out of its bag, hanging around my neck. I would frequently stop to take photos, of black camels and fields and flowers and patterns in the cloud. The last photo I took was of Manjunath (from my tour group) riding past a herd of black camels.

I function best when I do two things at a time. That morning I got over confident and did three. I was riding on a road 10 feet wide at 80 kilometres per hour. I was singing – though I’ve forgotten what I was singing. And I was thinking about something. My processor went nuts. While things were steady state on the road there was no problem. There was a problem, however, when I saw a bit too late that there was a massive herd of massive cows blocking my path further down the road.

There was no time to brake. I instead decided to overtake the herd by moving to the right extreme of the road (the cows were all walking on the road in the same direction as me). To my misfortune, one of the cows decided to move right at the same time, and I hit her flush in the backside. The next thing I remember is of me lying sprawled on the side of the road about five metres from where my bike was fallen. There was no sign of the cow. The bike was oozing petrol but I wasn’t able to get up to lift it up – presently others in my tour group who were a few hundred metres behind reached the scene and picked up my bike. And I don’t know what state of mind I was in but my first thought after I picked myself up was to check on my camera!

The camera wasn’t alright – it required significant repairs after I got back home, but I was! I had broken my fifth metacarpal, which I later realized was a consequence of the impact of the bike hitting the cow. There were some gashes on my bicep where the protective padding of my riding jacket had pressed against my skin. I still have a problem with a ligament in my left thumb, again a consequence of the impact. And that was it.

I had had an accident while traveling at 80 kmph. I had fallen a few metres away from the point of impact (I don’t know if I did a somersault while I fell, though). I fell flush on my shoulder with my head hitting the ground shortly. It was a rather hard fall on the side of the road where the ground was uneven. And there was absolutely no injury because of the fall (all the injury was due to impact)!

It was the protection. No amount of worry would have prevented that accident. Perhaps I was a bit more careless than I should have been but that is no reason for there not being an accident. When you are riding on a two wheeler at a reasonable pace on country roads, irrespective of how careful you are there is always a chance that you may fall. The probability of a fall can never go to zero.

What I had done instead was to protect myself from the consequences of the fall. Each and every piece of protective equipment I wore that day took some impact – helmet, riding jacket, riding gloves, knee guard, shoes.. Without any one of these pieces, there is a chance I might have ended up with serious injury. There was a cost I paid – both monetary and by means of discomfort caused by wearing such heavy gear – but it had paid off.

Black swans exist. However, worrying about them will not ease them. Those events cannot be prevented. What you need to do, however, is to hedge against the consequences of those events. There was always a finite possibility that I would fall. All I did was to protect myself against the consequences of that!

Despite contrary advice from the doctor, I decided to ride on and finish the tour, struggling to wear my riding glove over my swollen right hand – stopping midway would have had a significant adverse impact on my mental state which had just begun to improve. I’ve stopped worrying after that. Yes, there are times when I see a chance of some negative black swan event happening. I don’t worry about that any more, though. I only think of how I can hedge against its consequences.

The Aditya Birla Scholarship

I spent this evening attending this year’s Aditya Birla Scholarship awards function. Prior to that, there was a networking event for earlier winners of the scholarship, where among other things we interacted with Kumaramangalam Birla. Overall it was a fun evening, with lots of networking and some nostalgia, especially when they called out the names of this year’s award winners. My mind went back to that day in 2004, as I sat confident but tense, and almost jumped when I heard my named called out only to realize it was another Kart(h)ik!

You can read more about my experiences during that award ceremony here (my second ever blog post), but in this post I plan to talk about what the scholarship means to me. During the networking event today, one of the winners of the scholarship (from the first ever batch) talked about what the scholarship meant to him. As he spoke, I started mentally composing the speech I would have delivered had I been in his place. This blog post is an attempt to document that speech which I didn’t deliver.

People talk about the impact the scholarship has on your CV, and the bond that you form with the Birla group when you receive the scholarship. But for me, looking back from where I am now, the scholarship has primarily meant two things.

Back in the day, the scholarship covered most of my IIM tuition fee. When I’d joined IIM, my parents had told me that they wouldn’t fund my education, and I had taken a bank loan. However, the scholarship covered Rs. 2.5 lakh out of the Rs. 3 lakh I needed for my tuition fee, and the loan that I had taken for the remaining amount was cleared within a couple of months after I worked.

My first job turned out to be a horror story. It was six years before my ADHD would be discovered, but I was in this job where I was to put in long hours under extremely high pressure, and deliver results at 100% accuracy. I wilted, but refused to give up and pushed myself harder, and I’m not sure if I actually burnt out or only came close to it. But it is a fact that one rainy Mumbai morning, I literally ran away from my job, purchasing a one-way ticket to Bangalore and refusing to take calls from my colleagues until my parents told me that my behaviour wasn’t appropriate.

While my parents were broadly supportive, the absence of liabilities made the decision to quit easier. Of course I still had the task of finding myself another job, but I knew I would pull through fine even if I didn’t find another job for another six months (of course, I had saved some money from my internship at an investment bank, but the lack of liabilities really helped). The Aditya Birla Group, by funding my business school education, played an important role in my being free or financial obligations, and being able to chart out my own path in terms of my career.

My six-year career has seen several lows, aided in no small amount by my ADHD and depression, both of which weren’t diagnosed till the beginning of this year. I got into this vicious cycle of low confidence and low performance, and frequently got myself to believe that I was good for nothing, that I had become useless, and that I should just take some stupid steady job so that I could at least pay the bills.

During some of these low moments, my mind would go back to that day in September 2004 when I (at the end of the day) felt at the top of the world, having been awarded the Birla scholarship. I would then reason, that if I was capable of convincing a panel consisting of N. Ram, N K Singh and Wajahat Habibullah to recommend me for the Aditya Birla scholarship, there was nothing that was really beyond me. Memories of my interview and the events of the day I got the scholarship would make me believe in myself, and get me going again. Of course on several occasions, this “going again” didn’t last too long, but on other occasions it sustained. I credit the Aditya Birla scholarship for having given me the confidence to pull myself back up during the times when I’ve been low.

These are not the only benefits of the scholarship, of course. The scholarship has helped build a relationship with the Aditya Birla group. In the short run, when I won the scholarship, it helped me consolidate my reputation on campus. And last but not the least, it was a major catalyst in reviving a friendship which had gone awry thanks to some of my earlier indiscretions. Most important, though, was the financial security that scholarship offered, which made potentially tough decisions easier, and the confidence it offered me which has carried me through tough times.


Anxiety and computer viruses

I think, and hope, that I’ve been cured of anxiety, which I was probably suffering from for over six years. It was a case of Murphy’s Law taken to its extreme. If anything can go wrong, it will, states the law, and in those six or seven years, I would subconsciously search for things that could possibly go wrong, and then worry about them. And worry about them so much that I would get paranoid.

Let me give you an example. Back in 2008, after a four-month spell of unemployment, I had signed up with a startup. Two days after I signed, which was three weeks before I was going to start work, I started worrying about the health of the startup founder, and what would happen to my career in case he happened to croak between then and my joining the company! It had been a major effort on my part to try and get back to finance, and that job was extremely important to me from a career signaling standpoint (it played a major role in my joining Goldman Sachs, subsequently, I think). So I started getting worried that if for some reason the founder died before I joined, that signaling wouldn’t happen! I worried about it for three days and broke my head about it, until sanity reigned.

This wasn’t a one-off. I would take ages to reply to emails because I would be paranoid that I had said something inappropriate. When I landed in Venice on vacation last year, my office blackberry didn’t get connected for an hour or so, and I thought that was because they had fired me while I was on vacation. It would be similar when I would look at my blackberry first thing in the morning after I woke up, and found no mails. I needed no real reason to worry about something. It was crazy.

When a virus attacks your computer, one of the ways in which it slows down the computer is by running “background processes”. These processes run in the background, independent of what you intend to do, but nevertheless take up so much of your computing power that it becomes extremely hard to function. Anxiety works pretty much the same way. Because there is always so much going on in your mind (most of it unintended, of course), a lot of your brain’s “computing power” is taken up in processing those unwanted thoughts (the brain, unfortunately, has no way of figuring out that those thoughts are unintended). And that leaves you with so much lesser mindspace to do what you want to do.

So you stop functioning. You stop being able to do as much as you were able to. Initially you don’t recognize this, until you bite of more than you could possibly chew a number of times in succession. And then, having failed to deliver on so many occasions, you lose confidence. And lesser confidence means more worry. Which means more background process. And means diminished mental ability. Things can spiral out of hand way too quickly.

I’ve been on anxiety medication for over seven months now, and the only times when I realize how bad things were are when I happen to miss a dose or two, and there is relapse. And having been through it, trust me, it is quite bad.

On the positive side, the impact a well-guided medication process (administered by an expert psychiatrist) can have on anxiety is also tremendous. For the six years I suffered, I had no clue that I was under a cloud of a clinically treatable condition. I didn’t know that it was only a virus that had attacked my CPU, which could be got rid off with sustained dosage of anti-virus, and I had instead thought my CPU itself was slowing down, maybe rusting (at the ripe old age of late twenties). After I started responding to my medication, I was delirious with happiness, with the realization that I hadn’t become dumb, after all.

It was sometime in March or April, I think, when I realized that my medication had come into effect, thus freeing up so much mind space, and I started feeling smart again. When I met the psychiatrist next, I told her, “I feel exactly the way I felt back in 2005 once again!”.

On mental math and consulting careers

Sometime last week, the wife wanted to know more about management consulting, and I was trying to explain to her the kind of work that consulting firms do. I told her that the two most important skills to have in order to be a successful consultant are structured thinking and people skills, and in order to illustrate the former I put her through a “case” on the lines of those that consulting firms use in order to interview.

The importance of structured thinking, I explained, lay in the fact that not all problems that consulting firms pose have a definitive solution, and structure helps you hedge against not being able to generate a solution. In the worst case, if you follow this approach, you would have made a contribution to the client solely by putting a structure on their problem, and by enabling them to think better about similar problems that cropped up in the future. This is also the reason that consulting firms use the much-touted (and much-abused) frameworks – they are a good method of structuring the problem, I said.

I then went on to talk about how I’m not much of a structured thinker, and how I frauded my way in through that during my consulting interviews nearly six years back. On joining a consulting firm, I’d found myself thoroughly disillusioned and out of my depth, and finding that the job called for a completely different set of skills than what I possessed. The nature of problem solving, I found, was very different from the kind I’d been mostly exposed to, and enjoyed. I quit in a matter of months.

I went on to narrate a story from my B-school days. It was about the final exam of a second year course, and I’ve blogged about it. The question presented a business problem and asked us to find a solution for it. I thought for a bit, figured out the solution (with a bit of thinking it was obvious) and explained it two or three paragraphs. My friend had instead put a structure on the problem, and used all possible applicable frameworks in order to structure it. He has been working for a consulting firm since graduation, and I’m told he’s doing rather well. You know my story.

So we talked a bit more about problem solving approaches, and how I could possibly structure my business now that I’m an independent consultant (given that I’m not a particularly structured person). During the course of this conversation I happened to mention that most of my early problem solving was in terms of programming. And the wife jumped on this. “You are a mental math guy, aren’t you?”, she asked. I nodded, feeling happy inside about those days when I would do three-digit multiplications in my head while my classmates still struggled with “six in the mind, four in the hand” methods of doing addition. “And you’re an algorithms guy, always trying to find the easiest method to solve problems?”, she continued. Again I replied in the affirmative. “Then how the hell could you even think that you would do well in a job that requires structured thinking?”

She has a point there. Why didn’t I think of this earlier? The more pertinent question now is about how I’m going to structure my data modeling business since it’s clear that I won’t be able to pull off the classical consulting model.

Jobs and courtship

Jobs, unlike romantic relationships, don’t come with a courtship period. You basically go for a bunch of interviews and at the end of it both parties (you and the employer) have to decide whether it is going to be a good fit. Neither party has complete information – you don’t know what a typical day at the job is like, and your employer doesn’t know much about your working style. And so both of you are taking a risk. And there is a significant probability that you are actually a misfit and the “relationship” can go bad.

For the company it doesn’t matter so much if the odd job goes bad. They’ll usually have their recruitment algorithm such that the probability of a misfit employee is so low it won’t affect their attrition numbers. From the point of view of the employees, though, it can get tough. Every misfit you go through has to be explained at the next interview. You have a lot of misfits, and you’re deemed to be an unfaithful guy (like being called a “much-married man”). And makes it so tough for you to get another job that you are more likely to stumble into one where you’re a misfit once again!

Unfortunately, it is not practical for companies to hire interns. I mean, it is a successful recruitment strategy at the college-students level but not too many people are willing to get into the uncertainty of a non-going-concern job in the middle of their careers. This risk-aversion means that a lot of people have no option but to soldier on despite being gross misfits.

And then there are those that keep “divorcing” in an attempt to fit in, until they are deemed unemployable.

PS: In this regard, recruitments are like arranged marriage. You make a decision based on a handful of interviews in simulated conditions without actually getting to know each other. And speaking of arranged marriage, I reprise this post of mine from six years ago.

Gyaan From a Former All India Topper

CAT is less than a month away. Or more, depending on when you’re writing it. If any aspirants are reading this, I have just one piece of advice for you – which no one in any CAT Factory will give you. It’s about going for it. About batting like Sehwag. About reaching out far outside the off stump and playing every ball. I just want to assure you that percentages are in favour of this kind of a game.

In my zamaana, every correct answer in CAT gave you one mark, and every incorrect answer took away a third of a mark. Every question had four possible answers of which exactly one was correct. This negative marking had a completely psyching out effect on most takers, and people are afraid to go for it. And six years back, I liked it. For it made my own risk-taking strategy much easier – since I could now afford a larger number of errors.

The arithmetic is simple. Even if you have no clue about the question, and just put inky-pinky-ponky (or even better mark ‘C’, since years of research has proven that it’s the statistically most probable answer in CAT) you have one-fourth chance of getting it right – which gives a three-fourth probability of getting it wrong. And given the payoffs for correct and incorrect answers (1; -1/3) you can clearly see that the expected payoff of taking a completely random guess is ZERO!

So while this obviously rules out insane inky-pinky-ponkying, what it does tell you is that if you can eliminate at least one of the four choices, you are in the money! If you have to pick one of three possible answers, the expected payoff is 1/9 which is greater than zero. Yeah it doesn’t look very high but then the expected payoff is positive! So you need to go for it.

Back when I was in my 3rd year, there was some free mock CAT at IITM. And some of us 3rd years went just for the heck of it. I attemped 130 out of 150 questions, getting 90 right and 40 wrong. It still gave me a significantly higher score than any of my seniors (who were writing CAT that year) – most of whom attemped not more than seventy. Later that day a senior called me aside and told me that the art of CAT was about leaving questions. And that it was all about the questions that you left.

Leaving the ball makes sense in cricket where one mistake ends your innings. What if instead of ending your innings you were just deducted 2 runs everytime you got out? Would you still leave the balls outside off and play the waiting game? How on earth would you score runs if you were to leave every ball? It’s all about scoring, and you can score only if you attempt a shot.

I understand that CAT format has changed now and you have 5 possible correct answers for every question while the negatives are still at 1/3. Even then, if you can eliminate two out of the five answers (shouldn’t be too gouth), you have a positive payoff. And you must go for it. Keep in mind that you can’t score if you don’t play the ball.

I leave you with a video. The message is in the name of the song. Idu One Day Matchu Kano. This is a one day match dude. So you must go for every ball. And look to score.


I’ve never been the religious type. I seldom go to temples. I seldom go to temples in my own city. I do visit temples when I’m traveling, but that is more as a tourist attraction. I’ve been to Tirupati once (Boxing Day 1991) and to Mantralaya twice and am not keen to visit either place again. After my first visit there in 1990, I would consider the Annapurna temple¬† in Horanadu (near Chickmagalur) as my favourite temple. This was until a year ago when I visited it again and got pissed off by the crowds and formalities.

The amount I contribute to the Hundi in temples is also highly variable, and a direct function of how much I like the temple. I consider my contribution to the Hundi as my contribution for the upkeep and maintenance of the temple, and in support of the temple’s activities (for example, I tend to put in a higher amount in temples which serve free food). If I don’t like a temple, I just make a token contribution of Rs. 2 or Rs. 5 and flee. Also, I usually make my contributions to the Hundi, and not to the plate that comes along with the mangalaarathi. This is to ensure that the priest doesn’t kult my contribution.

Some temples do end up making me feel spiritual. It is hard to describe that feeling but let me tell you that it is the same that I felt when I smoked my first cigarette (and decided that smoking was too addictive to take up as a hobby and abandoned it). It is that feeling of inner calm. It is that feeling of being at complete peace with oneself. Sadly I haven’t felt that way at any temple since I started earning, else that temple might have been blessed with a fat contribution from my wallet.

I find the temples in North India too noisy. I remember literally running away from the ISKCON temple in Delhi six years ago because I thought it looked like a discotheque – loud devotional songs and people dancing. Today I went to a couple of temples near Connaught Place and it was similar – loud bhajans on one side, astrologers sitting all around the temple, and general disorder everywhere else. There was no way that temple could offer any peace or calm or any spiritual benefit. I fought with my mother when she insisted I should contribute at least Rs. 10 to the Hundi.

My contribution to temples is also an inverse function of its popularity – I usually contribute less at more popular temples because I can freeride on the rest of the visitors’ contribution. If it is a smaller temple and if i like it, I feel more responsible to contribute towards its upkeep.

And when I go to a temple, I always get archane done. That way, I definitely get some sugar candy!

And why do I not want to go back to Tirupati? Because I think it is too crowded to offer any kind of spiritual benefit. And Mantralaya? The last time I went there someone got a special pooja done in my name and as “prasad”, the swami there threw a towel on my back, and then threw an orange and asked me to catch it. I find that demeaning and don’t want to go back there again. Oh, and I wasn’t let in to the dining hall since I wasn’t wearing my sacred thread.