Truly Madly: Review

So the wife and I both decided to sign up on the dating app TrulyMadly, she to conduct research for her matchmaking service, and me as part of my research for the book that I’m currently revising. Based on our collective usage of our respective apps for about an hour, here are some pertinent observations.

  • Sexism: The wife can see salaries of men she is getting matched with, while I don’t get to see salaries of women being recommended to me. Moreover, women are allowed to “lurk” (and not have a public profile) on the platform, but no such thing for men. I’m surprised no one has called out TrulyMadly on their sexism
  • Job board: To list on the app you need to indicate your profession and job, and how much you are making. So if you are a woman on this site, apart from getting to check out men, you get to check out what jobs pay how much, and it’s not inconceivable that you use the app to find yourself a job.
  • Judgments: This should possibly go down under sexism again. Anyway, the wife has mentioned her qualifications as “MBA”, and she is only being shown men who are graduates of top B-schools in India. No such thing for me – women shown to me had all kinds of qualifications. It’s like TrulyMadly has decided that women should only date men who are at least as well qualified as them. Moreover, the app also decides that men can only date women who are shorter than them, though there’s a setting somewhere to change this.
  • Age bar: Based on my age (which I entered as 34), the app decided that I should only be allowed to check out women between the ages of 26 and 34. These can be moved around, in case I have fetishes outside this age range, but I’m shocked that they are not aware of the N/2+7 rule – based on which the lower limit should’ve been set at 24 (34/2+7) and not 26.
  • Gender imbalance: The app gave up on me after I rejected some half a dozen women, after which I deactivated my account and deleted the app. The wife’s app, however, continues to go strong, as she might have rejected some two or three dozen men by now (apart from having done research on what jobs pay how much). Just goes to show the gender imbalance on the app. I can imagine this leading to a lot of frustrated people, of both genders.

Ok that’s it for now. Any more insights you can read in my book (I hope to get it out in the next month or two)!

Moral of the story: Product management pays better than category leader.

Using my cook as an ATM

This happened ten days before high value notes were withdrawn, and suggests nothing about my cook’s political opinions or views. 

On 30th October 2016, I paid my cook his salary for October. As it was the usual practice, I paid him in cash. He asked me if I could do an online transfer instead.

It was the first day of Diwali, and he needed to send money to his wife in Bihar. And it being Diwali, all banks were closed, and there was no way he could send money to her. So he asked me if I could do that. And if I were anyway transferring money to his wife’s account, could I send her a bit more, he asked – he would compensate me for the extra amount in cash.

And so like that I used my cook as an ATM. He gave me his wife’s account details (it was such an obscure branch that I’d to google it to find the IFSC code – wasn’t in citibank’s lookup list). I added her as a “payee” and immediately IMPSd the amount to her. And my cook gave me the extra funds I’d transferred in cash.

Later on, I told him to install his bank’s app on his newly acquired fancy phone (with a Reliance Jio sim). I’m not sure he’s done that but considering how resourceful he is, it wouldn’t be long before he does that. And more of the Bihari cooks network in Bangalore do likewise.

Nandan Nilekani, in his championing of the UPI, likes to talk about how “anybody can be an ATM” with the new technology. This was an exemplary example of that.

The only fly in the ointment was that I didn’t need cash that day – after all I’d been to the ATM earlier that morning just so that I could get cash to pay my cook – so I ended up with a lot of cash that I didn’t need. Thankfully I was able to spend it productively before the ceased to be legal tender.

Following the withdrawal of high currency notes, I told my cook I would pay his subsequent salaries by bank transfer. He gladly agreed.

Damming the Nile and diapers

One of the greatest engineering problems in the last century was to determine the patterns in the flow of the Nile. It had been clear for at least a couple of millennia that the flow of the river was not regular, and the annual flow did not follow something like a normal distribution.

The matter gained importance in the late 1800s when the British colonial government decided to dam the Nile. Understanding accurately the pattern of flows of the river was important to determine the capacity of the reservoir being built, so that both floods and droughts could be contained.

The problem was solved by Harold Edwin Hurst, a British hydrologist who was posted in Egypt for over 60 years in the 20th Century. Hurst defined his model as one of “long-range dependence”, and managed to accurately predict the variation in the flow of the river. In recognition of his services, Egyptians gave him the moniker “Abu Nil” (father of the Nile). Later on, Benoit Mandelbrot named a quantity that determines the long-range dependence of a time series after Hurst.

I’ve written about Hurst once before, in the context of financial markets, but I invoke him here with respect to a problem closer to me – the pattern of my daughter’s poop.

It is rather well known that poop, even among babies, is not a continuous process. If someone were to poop 100ml of poop a day (easier to use volume rather than weight in the context of babies), it doesn’t mean they poop 4ml every hour. Poop happens in discrete bursts, and the number of such bursts per day depends upon age, decreasing over time into adulthood.

One might think that a reasonable way to model poop is to assume that the amount of poop in each burst follows a normal distribution, and each burst is independent of the ones around it. However, based on a little over two months’ experience of changing my daughter’s diapers, I declare this kind of a model to be wholly inaccurate.

For, what I’ve determined is that far from being normal, pooping patterns follow long-range dependence. There are long time periods (spanning a few diaper changes) when there is no, or very little, poop. Then there are times when it flows at such a high rate that we need to change diapers at a far higher frequency than normal. And such periods are usually followed by other high-poop periods. And so on.

In other words, the amount of poop has positive serial correlation. And to use the index that Mandelbrot lovingly constructed and named in honour of Hurst, the Hurst exponent of my daughter’s (and other babies’) poop is much higher than 0.5.

This makes me wonder if diaper manufacturers have taken this long-range dependence into account while determining diaper capacity. Or I wonder if, instead, they simply assume that parents will take care of this by adjusting the inter-diaper-change time period.

As Mandelbrot describes towards the end of his excellent Misbehaviour of markets , you can  use so-called “multifractal models” which combine normal price increments with irregular time increments to get an accurate (fractal) representation of the movement of stock prices.

PS: Apologies to those who got disgusted by the post. Until a massive burst a few minutes ago I’d never imagined I’d be comparing the flows of poop and the Nile!

Extremes and equilibria

Not long ago, I was chiding an elderly aunt who lives alone about the lack of protein in her diet (she was mostly subsisting on rice and thin rasam). She hit back citing some research she’d seen on TV which showed that too much protein can result in uric acid related complications, so it’s ok she isn’t eating much protein.

Over the last couple of years, efforts to encourage non-cash payments in India have been redoubled. The Unified Payments Interface (UPI) has come in, payments banks are being set up, and financial inclusion is being pursued. And you already have people writing about the privacy and other perils of a completely cashless economy.

Then you have index funds. This is a category of funds that is 40 years old now, but has gained so much currency (pun intended) in the recent past that the traditional asset management industry is shitting bricks. And so you have articles that compare indexing to being “worse than Marxism” and dystopian fiction about a future where there is only one active investor left.

All these are cases of people reacting to suggestions with the perils of the suggestion taken to the extreme. My aunt needs more protein in her diet, but I’m not telling her to eat steak for every meal (which she anyway won’t since she’s a strict vegetarian). The current level of usage of cash is too high, and there might be more efficiencies by moving more transactions to electronic media. That doesn’t imply that cash in itself needs to be banned.

And as I mentioned in another blogpost recently, we probably need more indexing, but assuming that everyone will index is a stupid idea. As I wrote then,

In that sense, there is an optimal “mixed strategy” that the universe of investors can play between indexing and active management (depending upon each person’s beliefs and risk preferences). As more and more investors move to indexing, the returns from active management improve, and this “negative feedback” keeps the market in equilibrium!

In other words, what more people moving to indexing means is that the current mixed strategy is not optimal, and we need more indexing. To construct scary scenarios of where everyone is indexing in response is silly.

Effectively, what we need is thinking at the margin – analysing situations in terms of what will happen if there is a small change in the prevailing situation. Constructing scare scenarios around what will happen if this small change is taken to the extreme is as silly as trying to find the position of a curve by indefinitely extending its tangent from the current point!

Bayesian recognition in baby similarity

When people come to see small babies, it’s almost like they’re obliged to offer their opinions on who the child looks like. Most of the time it’s an immediate ancestor – either a parent or grandparent. Sometimes it could be a cousin or aunt or uncle as well. Thankfully it’s uncommon to compare babies’ looks to those who they don’t share genes with.

So as people have come up and offered their opinions on who our daughter looks like (I’m top seed, I must mention), I’ve been trying to analyse how they come up with their predictions. And as I observe the connections between people making the observations, and who they mention, I realise that this too follows some kind of Bayesian Recognition.

Basically different people who come to see the baby have different amounts of information on how each of the baby’s ancestors looked like. A recent friend of mine, for example, will only know how my wife and I look. An older friend might have some idea of how my parents looked. A relative might have a better judgment of how one of my parents looked than how I looked.

So based on their experiences in recognising different people in and around the baby’s immediate ancestry, they effectively start with a prior distribution of who the baby looks like. And then when they see the baby, they update their priors, and then mention the person with the highest posterior probability of matching the baby’s face and features.

Given that posterior probability is a function of prior probability, there is no surprise that different people will disagree on who the baby looks like. After all, each of their private knowledge of the baby’s ancestry’s idiosyncratic faces, and thus their priors, will be different!

Unrelated, but staying on Bayesian reasoning, I recently read this fairly stud piece in Aeon on why stereotyping is not necessarily a bad thing. The article argues that in the absence of further information, stereotypes help us form a good first prior, and that stereotypes only become a problem if we fail to update our priors with any additional information we get.

The one bit machine

My daughter is two weeks old today and she continues to be a “one bit machine”. The extent of her outward communication is restricted to a maximum of one bit of information. There are basically two states her outward communication can fall under – “cry” and “not cry”, and given that the two are not equally probable, the amount of information she gives out is strictly less than one bit.

I had planned to write this post two weeks back, the day she was born, and wanted to speculate how long it would take for her to expand her repertoire of communication and provide us with more information on what she wants. Two weeks in, I hereby report that the complexity of communication hasn’t improved.

Soon (I don’t know how soon) I expect her to start providing us more information – maybe there will be one kind of cry when she’s hungry, and another when she wants her diaper changed. Maybe she’ll start displaying other methods of outward communication – using her facial muscles, for example (right now, while she contorts her face in a zillion ways, there is absolutely no information conveyed), and we can figure out with greater certainty what she wants to convey.

I’m thinking about drawing a graph with age of the person on the X axis, and the complexity of outward information on the Y axis. It starts off with X = 0 and Y = 1 (I haven’t bothered measuring the frequency of cry/no-cry responses so let’s assume it’s equiprobable and she conveys one bit). It goes on to X = 14 days and Y = 1 (today’s state). And then increases with time (I’m hoping).

While I’m sure research exists some place on the information content per syllable in adult communication, I hope to draw this graph sometime based on personal observation of my specimen (though that would limit it to one data point).

Right now, though, I speculate what kind of shape this graph might take. Considering it has so far failed to take off at all, I hope that it’ll be either an exponential (short-term good but long-term I don’t know ) or a sigmoid (more likely I’d think).

Let’s wait and see.

Andhra Meals in Religious Rituals

A long time back I’d compared massage parlours in Bangkok to Andhra meals, where there is a “basic menu” (the core massage itself) which everyone orders, on top of which other add-ons (such as happy endings) can get tagged on.

Today, while performing a religious ritual (it’s 10 days since my daughter was born, so there was some ceremony I’d to perform), I realised that every religious ritual, happy or sad, also follows the “Andhra meals” principle.

So the “meals” part is the stuff they teach you to do as part of your daily “sandhyavandane” ritual immediately after your thread ceremony. Starting with the aachamana (keshavaaya swaaha, narayanaaya swaaha etc), going on to reciting the Gayatri mantra, repeating the aachamana several times in the middle, and then ending by apologising and atoning for all the mistakes in the course of the ritual (achutaayanamaha, anantaayanamaha, govindayanamaha, achutanantagovindebho namaha).

This is the basic sandhyaavandane you’re supposed to perform three times every day, and the interesting thing is that most other rituals are add-ons to this. Be it a wedding ceremony, worship of a particular god on a particular festival or even a death ceremony, all these parts remain and don’t go away. What changes from ritual to ritual are the add-ons, like the meats you might order during Andhra meals.

And so in the wedding ceremony, there is the wedding itself. In a death ceremony, there’s all the part where you wear the sacred thread the wrong way round (praacheenaavEti) and build rice-til balls (piNDa – have you noticed how similar they are to sushi?). While worshipping a particular god, you perform the worship in the middle of the regular sandhyaavandane ritual. And so forth.

I must say I’m fairly impressed with our ancestors who devised this “modular form” of performing rituals. What rocks about this practice is that pretty much everyone who wants to perform these rituals will know these rituals (the “basic Andhra meals”) bit, which makes it that much easier to “consume” the “extra fittings” appropriate to the occasion.