The Logarithm of Love (Ice Cream Headache)


In 1960, Smokey Robinson’s mama dropped some serious truth when she insisted he better Shop Around. Given the decade, Smokey probably assumed her wisdom came from a woman’s deep understanding of bargain shopping, but I prefer to think she was simply keeping up with modern trends in mathematics.

Around that same time, numbers guys around the world were turning their attention to a decision-making dilemma they dubbed The Secretary Problem (also The Marriage Problem). Since the parameters of the problem are applicable to many real world situations, and since I choose not to indulge the sexist world of the Mad Men era, I call it the Ice Cream Headache.

Imagine yourself in an ice cream shop facing dozens of flavor options. You have to decide on just one, and ideally you want to choose the very best of all. The rules are simple: first, your choices are finite. (Even though Baskin Robbins lies and offers more than 31 flavors, they still don’t offer “infinity” flavors.) Second, you can sample flavors, but only one at a time, only once each, and you must make a decision immediately upon tasting – choose it, or pass. Finally, there are no ties. One is decidedly the best (for you).

To maximize your chances of walking away with The One, it turns out “shop around” really IS the best strategy – to a point. Mathematicians came to find that the optimal approach is to always reject the first 36.7% of flavors you try (that happens to be 1/e for all you natural logarithm fans out there), then choose the next flavor that tastes better than anything that has come before.

Say there are nine flavors total. This optimal method means we will taste the first randomly selected three and not choose them, no matter what. The odds of The One being in those first three (which means we will definitely NOT win the game) is 33%. The other 67% percent of the time, we still have a chance.

After rejecting the first three, we will choose the very first flavor that tastes better. If we happened to taste the second best flavor in the first three but not The One – the odds of which is 25% – we are guaranteed a win. Only The One will taste better, so only The One will be chosen, no matter how long it takes us to get to it. The remaining 42% of the time, victory depends on when in the subsequent tastings The One appears.

When the math is said and done, probability shows that employing this strategy to the Ice Cream Headache results in victory – choosing The One – at minimum 37% of the time, which is the best chance possible and far better than choosing at random.

Sure, in real life we are free to piss off the ice cream vendors as we test every single flavor over and over until we are either satisfied with our decision or just satisfied, but the parameters of the Ice Cream Headache are remarkably realistic when it comes to dating.

In love, we generally get one shot at evaluation – Burton and Taylor notwithstanding. Likewise, the choice is usually a now-or-never situation. (We may dream of “sampling” a person and then getting to try all the other people too before ultimately deciding, “You are the best,” but in reality that ends with a “Screw you, I’ve moved on” and a drink in the face.) Finally, even with today’s online resources, we still have a finite number of candidates.

Applying the lessons of the Ice Cream Headache to a partner search yields some interesting results.

For one, it helps redefine the idea of “success”. We usually view situations as win or lose, but mathematics has a third option: draw. Victory in the Ice Cream Headache is walking away with The One, but failure isn’t everything else; failure only happens if we walk away with a flavor that is NOT the best. Remember that 33% chance The One was in the automatically rejected first group? In that case, the player would never choose any flavor, because nothing would ever meet the requirement of outperforming everything prior. In life terms, the player stays single. I like the idea of a single life being a “draw” rather than a loss.

More significantly, the Ice Cream Headache validates the practice of living a little before settling down. The average life expectancy of an American woman is 82 years; 77 for American men. If we apply the “discard the first 36.7%” rule, no one should even consider choosing a life partner before age 30 or 28, respectively.

To apply the strategy more specifically to our dating years, let’s say no one dates seriously before 15, and we reserve the last 10 years for writing memoirs and bowling. That leaves 57 shopping years for women, and 52 for men. Again, if we automatically pass on the first 36.7% of candidates, that translates to 20 years of dating before possibly making a choice (19 for men). Starting at 15, that pushes the start of decision time to our mid-thirties.

Yes, this simplifies things with the premise that potential mates will appear at a steady rate across our dating years (now more likely with the internet), but the end result is still valid. Statistically, the optimal strategy over a lifetime for successfully ending up with your ideal flavor is to not get serious about choosing until sometime after 30. Mama was right: you better Shop Around.

Of course, this still doesn’t solve the problem of that awesome mocha chip gelato you finally go for deciding he doesn’t want you. But it helps.

I Was Told There Would Be No Math at This Debate (Statistics Part II)


Odds are, someone at some point has quoted Einstein’s definition of insanity to you: “Doing the same thing over and over again and expecting different results.” I love this quote for several reasons, the top two being that there is no evidence Einstein ever said it and it is not what insanity actually is. Yet somehow, by people saying it over and over in hope that it is true, it has become true in our conventional wisdom. Isn’t that the kind of paradox that is supposed to rip a hole in space-time and make the universe eat itself?

The dictionary definition of insanity is being deranged or unsound of mind enough to be divorced from reality and thus responsibility. Which nicely demonstrates the root of the problem with our current public discourse – it is Einstein Nutters versus Webster Loons.

Someone needs to impose some Nurse Ratched-level tough love on the world, so here I am, with math.

Back in January, I applied Bayesian reasoning (probabilistic thinking) to relationships, in order to get a better understanding of how illogical I often am in matters of the heart. It was fun! And I started to notice something quite interesting about the math, something that has been increasingly relevant as the clash between Science and Faith has escalated.

To recap: Bayesian reasoning is a process that involves estimating the likelihood of things, then reassessing that likelihood with each new piece of information. In short – and I know this is a dirty word – Bayesian thinkers evolve their ideas over time, getting ever closer to understanding.

If this sounds familiar, it is because probabilistic thinking is how we learn. Hey, that thing on the stove is shiny and pretty – I bet it will feel good too. Ouch. Nope. That did not feel pretty. Maybe pretty things don’t always feel good. Hey, that tiger over there is really beautiful. Maybe this time… and so on. Eventually, we get a feel for the odds (or die).

The formula representing this process – Bayes’ Theorem – is simply a mathematical expression of logic at work. It centers on three variables: our original level of certainty about something (x), the probability of this new info (Ouch) if that something is true (y), and the probability of this new info if that something is not true (z). That’s it!

When we reassess in the face of new information, we simply multiply our original level of certainly by the probability that our theory is still true (xy), then divide that by all possibilities – our original certainly (x) times the probability of true (y) PLUS our original uncertainty (1-x) times the probability of the theory being false (z). In math, that reads: (xy) / [(xy) + (1-x)z]

That’s the worst of it, I promise. What I find most interesting is how the impact of new information changes the more confident we are at the outset. Let me demonstrate with an example involving something totally uncontroversial right now: birth control.

Take two people, one who is super confident that I am a good little girl who keeps her knees closed (we’ll call him “My Dad”), and another who is willing to bet the farm that I am a total slut (“Rush Limbaugh”). They are both men, because involving a woman in a conversation about birth control would be ridiculous. Now, what happens to their respective outlooks when we introduce a new piece of information into their worlds: my use of birth control?

My Dad starts out with only 10% concern that I am a floozy (x=.1), while Rush is 90% sure I am sex crazed, since I am unmarried (x=.9). Variable y is the probability that I would use birth control if I am indeed a slut, which is clearly about 95% – who else would use birth control? Variable z is the probability that I would use it if I am not. Since women are either virgins or whores, that’s maybe 5%.

When we plug those probabilities into the formula, we see that My Dad, who is faced with contradictory information, skyrockets to a new 68% certainty that I am a daughter of questionable morals. As for Rush, he goes from 90% sure to 99% sure I am easy. Had we presented them with opposite information – like a purity ring on my finger – My Dad’s fears of parental failure would have dropped from 10% to .6%, and Rush would suddenly have to grapple with a mere 32% chance of my nymphomania.

Of course, my probabilities here are extreme, but the formula holds. The more confident we are in a theory at the outset, the more devastating contrary information becomes. As it should be! If we truly think an outcome is “inconceivable” and then it happens, we either have to admit that we were very likely wrong, or accept that the word “inconceivable” does not mean what we think it means.

But a funny thing happens when confidence becomes absolute certainty: new information loses all impact. When x=1 (we are 100% sure of something), the formula reduces to y/(y+0z), which equals 1 no matter what y and z are. When x=0 (“Inconceivable!”), the fraction becomes 0/(0+z), which is always zero.

In other words, there is no amount of evidence, experience, or new information that will change the mind of someone who has absolute certainty. Proving once and for all with math that there is no arguing with believers. (Or Beliebers – ugh.)

If you got this far, you are probably tired, because math is hard. Not in the sense that it requires a Y-chromosome (I’m looking at you, Larry Summers), but in the sense of hard work. Math is work; logic is work; being open minded requires the effort of reassessment. Faith, on the other hand, is easy. Not real faith, as defined in the dictionary (“belief in something for which there is no proof”), but the Faith demonstrated too often these days: belief despite all evidence of any kind.

You want the kicker? Thomas Bayes, from whom Bayesian reasoning gets its name, was an 18th-Century minister. I think it’s time for the universe to eat itself now.



There are a plethora of reasons why I love Louis C.K. He is smart and funny, a good dad, and definitely satisfies my addiction to redheads. But his biggest “pro” is that his television show is beautiful and brilliant.

To avoid getting “spoil-y”, I won’t go into detail about the episode I watched last night. Suffice it to say it involved “Louie” having and RDT (relationship defining talk) with his Eggplant of the moment. Upset because any and all sincerity is met with defensive humor, he wants her to express an honest emotion for once. She says, “I can’t do that. Can’t it be okay that there are just some things I can’t do?” And then the scene ends.

Leaving the question unanswered is beautiful because… well, because that is a big question for any potential couple, isn’t it? How each of us would choose to answer it says a lot about what we value in relationships, and ending the scene there lets each viewer answer it for herself. Louis C.K. accomplished a Sopranos-finale-type litmus test, except without being a dick to his fans.

I would have to answer that question with a sad, “no”, or at least a “probably not”, and it is all because of what my girlfriend and I defined several years ago as “The Three F’s” of a good relationship.

At the time, she was dating a guy we both adored (though not in a romantic way for me; that would have been messed up). On paper they were perfect for each other. He had everything she was looking for in a guy: he was tall, he was handsome, he was funny; he had a budding career and did well at parties; he had a good car, good friends, and made good money. Everything on her list was checked off. And yet…she was unhappy.

The thing is, in addition to having everything on her list, this guy also had an inclination to “keep it light”, meaning when shit went down, he went away. Career trouble, sick parents, his own family drama – no matter the issue, his answer was to close his eyes and plug his ears until it was over. Still, she stayed with him, because…the list.

“Forget the list,” I told her. Lists are for grocery shopping and little kids at Christmas. There is no relationship Santa, despite what Christian Mingle and the creepy eHarmony guy would have us believe. People need to lose their lists.

She countered that it is probably not a good idea to have no criteria for a mate; at the very least “no scrubs” should be a goal. So we compromised with a new list: one with the only three things that matter (and we added alliteration, because alliteration makes everything better).

Here are The Three F’s: Feed me, Fuck me, Fascinate me. If a partnership has all three, nothing else matters. Without even one of them, it will never work.

Fuck me: duh. This one is pretty self-explanatory. There must be sexual chemistry for a relationship to survive. I have been with a few men who, for various reasons (medication, Catholicism, homosexuality), were not that into being intimate, and it doesn’t take long for the dynamic to get irreparably weird.

Fascinate me: beauty fades, bodies sag, and even with sexual chemistry two people will eventually need to find each other interesting. Pretty but dumb is great in the short term, but for the long haul there needs to be a mind at work. If you don’t make me think, or laugh, or see things differently, I have no use for you. If you don’t find me interesting, ditto.

Feed me: aye, there’s the rub. For me, this has been the hardest criterion to satisfy, and to my detriment the one I have been most willing to overlook. In the literal sense, yes, it can mean “have a job” (or at least be able to feed yourself), but here it means feed each other emotionally. Be able to have a conversation about feelings, no matter how awkward. Be able to care about my life and my day. Be able to be there for me, even when I’m too stupid to know I need you (especially when I’m too stupid to know I need you).

My friend’s boyfriend was incapable of feeding her, and that is why no amount of height, handsome, or humor could make her happy. I have suffered from an unfortunate fondness for artists, narcissists, and depressives – which are three different ways of saying “emotional cripples”. And as much as I want “Louie” to be happy, I want him to say, “No, it’s not okay” to his Eggplant, because two out of three isn’t enough.

Look at it this way: the Suitable For Work version of The Three F’s is the mnemonic PIE (physical, intellectual, emotional). Without the Emotional support, all you have is PI. Any good math teacher will tell you that pi is irrational.

One Fish, Three Fish, Big Fish, Me Fish (Or, What I Learned on my College Vacation)


One day, in my Senior year of high school, something unexpected happened to me in the middle of calculus: I didn’t get it. I have no memory of what mathematical principle we were learning that day, but I vividly remember the frustration of being confused. It had happened to me only once before (with math, I mean – I “didn’t get” the rest of life all the time), when my 5th-grade class learned “greater than” and “less than” (“>” and “<”).

Back then, I had stared at those little arrows for hours, trying to see the difference between them that everyone else could see. Was one wider than the other? A more acute angle? Was there something wrong with the printing on my paper? It simply never occurred to me that they were pointing in opposite directions.

Eventually, light dawned on marblehead, but for what felt like weeks (and was probably only days), it was as if everyone spoke a language I just couldn’t comprehend. Like how people describe the experience of having a mild stroke – or a conversation with hipsters.

In calculus class that day, those feelings of vertigo came rushing back, and it was a formative day for me because of two things that happened in response. First, unlike in 5th grade, this time I raised my hand and asked for clarification. Since I had come to define my self-worth by my academic ability, it was no small thing to ask for help. It is also why it pissed me off when, instead of answering, my teacher told me to see her after class. I felt that my years of patient listening to the answers to everyone else’s questions had earned me a little class time, so I asked again – and a third time when she politely deflected.

I have no idea why this otherwise-wonderful math teacher refused to address my question in class. Maybe I was missing something obvious again, or maybe we were behind schedule or she thought I was punking her. What I do know is that her denial made me feel that my questions didn’t have value – and the memory of that feeling hovers over me as a cautionary tale every moment that I stand in front of my own students now.

The second thing that happened that day is that, not two periods later, my friend Doug – who would not have understood calculus if Jaime Escalante himself explained it – came up to me at my locker and said, “I hear you messed up in math class today.” Apparently, word had spread around school, and there was a fair amount of Schadenfreude at the fact that Kate, Captain of the Math Team, had “messed up” in calculus.

My initial instinct was to tell Doug that if having a question constituted a mistake then he must be the biggest disaster since the Hindenburg, but instead of lashing out I decided to listen to my second thought: “F*ck this, I need a bigger pond.”

That day, my outlook toward college went from terror I would fail to remain the best to ardent desire for a place full of more-accomplished peers. When the miracle that was my Harvard acceptance letter showed up a few months later, I knew I had found the Lake Superior I was looking for.

Humility is a wonderful thing, and being humbled is even better. Those first couple of years in Cambridge, the knowledge that I was surrounded by so much talent freed me to try all kinds of new things. I figured, “if I’m not going to be the best at anything, what the heck? Let’s explore!” I took the hardest freshman math class there was and actually hung in there for a few weeks; I took Ancient Greek with a bunch of people who already spoke Latin and only freaked out a little at my F on the first midterm; I volunteered for Model Congress despite almost no awareness of current political events, and I did perhaps the scariest thing of all: left the comfort of mathematical certainty for the subjective world of the English department.

As I reached my last couple of years, the freedom of the big pond turned more into a driving force. Swimming with bigger fish had boosted my confidence, to the point where I was frustrated I wasn’t bigger myself. My desire to make a splash (or even a plop) drove me toward leadership positions I would never have considered before, and even inspired me to audition for a spot as a commencement day speaker – something I still can’t believe I actually attempted.

This weekend, the class of ‘99 returned to Cambridge for our 15th reunion, and my fellow Harvardians continue to represent for me those two pillars of a happy life: confidence, and humiliation (er, humility). The ambition, drive, and success of my classmates is inspiring, and reflects back on me the courage to earn my spot within their ranks – or at least to try. At the same time, I am acutely aware that no matter how good I get at anything, there will always be someone bigger or better. Probably someone I have seen contemplate philosophy and quantum physics while high.

Sure, knowing I will never be “the best” can be a little depressing at times, and occasionally makes me want to go drown myself in a small pond somewhere. But mostly, I find it a comforting assurance that I will never be bored. No matter how far I get, there will always be those who challenge me to swim farther; there will always be new waters to explore.

As long as those waters aren’t the Charles River – that shit is still toxic.

Looking Glass Houses


There is an old LSAT problem I teach my students, about the paradoxical behavior of suburban birds who flee danger by flying smack into the sides of houses instead of hiding in nearby vegetation. The explanation for all the avian suicide is that the windows in the houses reflect surrounding foliage – so the birds think they are hiding – but that’s not why I like to teach the problem. Mostly, I like to teach it because the image of birds flying head-on into windows makes me giggle (call PETA if you want, but stupidity is funny in every species). Before I go down for schadenfreude, though, let me add that I also love this image as a metaphor; it is a moment to which I think we can all relate.

It is shocking, those moments when you realize that the space you occupy is significantly smaller than you thought it was, and it can happen to us mentally just as much as it can physically. While I have walked into my share of floor-to-ceiling mirrors (I know I am not the only one who wishes they would stop using these to decorate small restaurants and hotel lobbies), the times when I have slammed up against the invisible walls of my own mind have been far more jarring. These mental walls have been on my mind lately because around this time every year I revisit one of my earliest.

This past weekend, we celebrated my parents’ birthdays, one on Saturday then the other on Sunday. Not because I am a Joffrey Baratheon-style child of incestuous twins who refuse to share a party, but because my parents are almost exactly the same age. Nine hours separate their births – though since those nine hours straddle midnight they do have different birth dates. If you don’t think my mom makes the most out of the one calendar day when my dad is technically older than her, then you don’t know women very well. Or marriage.

Adult me knows that this birthday coincidence doesn’t happen very often, but it took many years for younger me to realize that my family’s unique situation had formed an invisible barrier around my perception of reality. Growing up, I assumed that every married or dating couple was the same age, and that I would obviously end up with Leonardo DiCaprio because his birthday is two days after mine (I was willing to overlook the different birth year). My November birthday theory went bust the first time I dated a fellow Scorpio and realized that, if this was the guy for me I should seriously consider being a lesbian, but the second wall is one I walked into many, many times (and still do from time to time). It doesn’t help that my brother chose to marry someone only five days older than he is – give a girl a break!

Those little things that in truth are simply the quirks of our particular circumstance so easily become our expectations for reality without us noticing. My brother and father are both left-handed, and so are the brother and father of my life-long best friend. When our families would eat together we always sat boy-girl-boy-girl, so all the men could cut their meat without anyone getting elbowed. We women were all righties, and boom: another invisible wall boxed me in. Handedness and gender were the same. To this day, I still have to stifle immediate envy when I meet a left-handed girl; I have to remind myself that it does not make her more exotic and tom-boyish than I could ever hope to be. Also, all right-handed boys are not automatically gay (if only it were that easy – high school and college would be far gentler on the hearts of so many young girls…).

Walking head-on into a personal bias always leaves me momentarily stunned, because it forces me to question my perception of the world. But I have run into enough now that I know they are there, and I am always on the lookout for the next one. Some of these invisible mental walls are relatively harmless, like my assumption (until recently) that everyone is as aware of their own heartbeat as I am, but others can be more dangerous – like the idea that everyone has two parents who read to them and love them, or that everyone is born with the tools to learn, or feed themselves, or deal with adversity. Coming to Los Angeles ran me straight into my assumption that people generally mean what they say (that one really hurt), and my belief in the importance of tangible markers for success.

We are the products of our assumptions, and our assumptions reflect our history, which is part of why I love teaching logic so much. The more we start to recognize the many assumptions that block our view, the more we can see those invisible walls and, instead of running into them, start to peek around them. We are Minotaurs, imprisoned in mental mazes of our own making, slowing working our way out from the center. With each new wall we crash into, we get a little closer to escaping the sheltered spaces we have built for ourselves to see the real world outside.

Fortunately for me, I actually am half bull – since I am the child of two Taurus parents. I like to think it gives me a fighting chance. Happy Birthdays, Mom and Dad; thanks for giving me the tools to navigate this labyrinth of life.

Poker Face (That’s What She Said)


In 2012, I wrote a screenplay about a girl who starts an underground casino on the Princeton campus in order to pay for her suddenly scholarship-less senior year. Since the only personal experience I have with gambling is playing “Vegas rules” solitaire on my computer when I’m procrastinating, I had to do quite a bit of research before I could write it. One of my favorite discoveries came when reading about the psychology of the greatest poker players.

In poker, as in much of life, there are four possible outcomes every time we play a hand: we can play well and win (yay!); we can play poorly and lose (boo!); we can play poorly and win anyway (yay!); or we can play well and still lose (double boo!). Most of us – mere humans that we are – are emotional creatures, or what Lord Voldemort would call “weak”. While Voldy’s assessment is a tad harsh, it is true that our emotional dominance tends to result in reactions like those of the parenthetical cheerleader above (Mr. “Yay! Boo! Yay!”). We focus primarily on results – winning is good, losing is bad.

But some people are ruled more by logic instead – Sherlock Holmes, the main character on Bones, and Mr. Spock to name a few. These people would have very different reactions to the four possible outcomes, because they don’t focus on results as much as process when judging performance. Good poker players know that long-term success demands that they learn to think this way – to be more Spock than jock – and they have the experience and maturity to “make it so”. (Yeah, yeah, I know that’s Picard’s line. Give me a break.)

A professional poker player understands that sometimes, life happens (or, in their case, luck). Sometimes, you play the odds perfectly, and read an opponent just right, but he still draws that one improbable card that gives him the one had that can beat you. Yes, this hand is lost, but what matters is that it was played well. The successful poker player walks away from this situation satisfied, and would be similarly displeased if the roles had been reversed and she had won on a lucky card rather than skilled play.

Daft Punk may be up all night to get lucky, but the best poker players are up all night to hone their craft.

Empirically, I know this to be the path to success. I tell my LSAT students relentlessly, because I have seen it bear out time and again: focus on the process instead of the score, and not only will you be happier, you will also ultimately see much better scores. It is logic. It is proven. It is also much easier said than done.

Most people hear about my romantic travails in 2012 and immediately want to give me a hug, buy me a cookie and tell me it’s all going to be okay. I won’t lie – it was emotionally rough. But I look at the year as a success because I finally learned to start looking at the world with the eye of my inner poker player. Yes, I had two relationships end in one year, and yes, both times it was because he chose to be alone rather than to be with me. I could easily look at that, see two defeats, and decide to try being a different person, but the outcomes don’t bother me. Sometimes, two people just aren’t meant to be together – and boy, did I not belong with either of them. Instead, I choose to focus on how I handled things once that was known.

Neither of the two men involved was capable of sustaining a long-term relationship. The first was a true loner; he loved me, but after a year his wanderlust started making him more and more distant. When this became too apparent to ignore – along with the fact that he was never going to own up to it – I sat him down and told him to figure out what he wanted. If it was me, fantastic, I was totally in; but if it wasn’t, he needed to go so I could find a man who did want me. He left and it was heartbreaking, but for the first time in my life I had handled a romantic entanglement with complete maturity and strength. Even though I lost, I walked away with pride because of my good play – and hoped to continue such behavior in the future.

Naturally, my handling of the next guy was a disaster. He was self-absorbed, closed off, and a really good liar. Even though, in the few short months we were together, my inner voice kept screaming, “Get out! You deserve better than this!” I chose to believe him every time he begged for patience and forgiveness. My last capitulation – an agreement to pause, let the holidays pass, and regroup after life was calmer and heads were clearer – was rewarded with an abrupt break-up speech en route from one Christmas party to another. It really couldn’t have ended better.

Still, even though I consider that last relationship more of a win than a loss (being single is so much better than being with him), I seethe with shame every time I look back at it because I really could not have played it worse. Well, okay, I could have “accidentally” gotten pregnant by him to appease my biological clock – THAT would have been worse. But you get my point. Any outcome based on bad play is far less desirable than even a loss after good.

Poker mentality is a refreshing alternative to our usual results-based evaluations. It is especially vital for sanity when taking the life or career path less traveled. Sure, it’s a little annoying that to most of my friends I appear far more upset about (and thus attached to) the ass than the guy I actually loved, but that’s on them for making assumptions. I’ll take my healthier mental state any day.

Of course, it is still harder to practice than to preach. Not only do we have to learn to focus on process over outcome in the face of a culture that overwhelmingly cares about results, but we also have to learn to trust our own evaluation of that process. This is especially hard in an imperfect and uncertain world, where it is often difficult to distinguish bad luck from bad strategy. Did this relationship or project fail because it just wasn’t meant to be, or because there is something wrong with my selection process? Most of the time, it’s a little bit of both.

But just because something is hard doesn’t mean it isn’t worth doing. We just need to practice. The more experience we collect, the easier it will become to judge our process and then to trust that judgment. Start small (my oven timer broke and the cookies burned, but the batter tasted great), work up to the bigger things (sure, my kid’s a rocket scientist, but what matters is that I taught her to be nice to people), and counteract inherent uncertainty with self-forgiveness.

If we focus on the method instead of the goal, we will find more pleasure in the process, and with a little luck see better outcomes than we ever imagined. (That’s what she said.)

Love, Damn Love, and Statistics


Okay, kids, let’s get down and nerdy for a little bit. Fair warning: there will be math in today’s session. I promise to make it fun and not scary (says the former captain of her high school math team), and I assure you there will be no test after. To every student past, present, and future who ever rolled his eyes to the heavens in math class and asked, “When am I ever going to use this in real life?” I answer with the eternal wisdom of Shania Twain: “From this moment on.”

I have been reading about Bayesian reasoning lately (in Nate Silver’s awesome book about prediction – and if that surprises you at all, I invite you to glance up at the title of this blog one more time), which is a school of probabilistic thinking employed by, among others, the most successful gamblers. According to Marvin Gaye (and confirmed by anyone who has ever been willing to eat at a Taco Bell), life is a gamble, so I naturally wondered how Bayesian reasoning might apply to areas more relevant to me than sports betting. Now, I consider myself a fairly logical and scientific individual – mostly because I am ridiculously logical and scientific – but what I came to realize about my approach to other humans kind of blew my mind.

A little background: Thomas Bayes was an 18th century English minister who sought to resolve the paradox of a benevolent God and the existence of evil. See? I told you this would be fun. In very brief terms (my apologies to any theologians or philosophers our there), his answer revolved around the idea that the imperfections we see in the world are ours, not Gods, because our knowledge is never complete. In other words, if we see too much evil in the world, it doesn’t mean that there isn’t overall good, but rather that we are not seeing the whole picture. I’ll save the larger debate about good versus evil for my next Lord of the Rings party, but what matters most is that Bayes introduced the concept that humans learn about the world through approximation rather than certainty – getting closer and closer to the truth with each new piece of the puzzle, but never knowing the absolute truth.

Bayes’s chief rival in those days was David Hume, a Scottish philosopher to whom I’m going to give the benefit of the doubt and assume was drunk a lot, because he equated rational belief with certainty. Talk about depressing. Here’s a quick example to demonstrate the disparity: imagine you have moved to Los Angeles with no prior knowledge of it climate, history, or reputation, presumably because you have never seen a movie, read a book, watched TV, or met a Californian. This makes you either an alien or Amish, but I digress. Day 1: it is sunny. Aw, that’s nice. Day 2: sunny again. Cool. Perhaps this is a trend. Day 3: still more sun, and so on, and so on. The Bayesian thinker will grow more confident with each passing day that tomorrow’s weather is likely to be sunny – never fully reaching 100% certainty, mind you, but getting darn close. Even when, 300 days in, it suddenly rains (in case you haven’t heard, we’re experiencing an epic drought here in LA), the Bayesian will still be pretty sure the next day will be sunny. Those on Team Hume, on the other hand, reason that since we can’t be certain about tomorrow’s weather, it is equally rational to predict sun and rain. This sounds like a pretty high-stress way of life to me, and a recipe for an early ulcer. No wonder he drank.

Now we’re all caught up: Bayesian reasoning balances past knowledge with new information to make a probabilistic prediction about what is true, while those on Team Hume remain susceptible to the false positive – when the newest info is given disproportionate importance. I don’t know about you, but one seems like a far more productive way to interact with the world. (And if you think I mean the second way, then, well, you should run for Congress. You would do well there.) But when it comes to pursuing the opposite sex, or the same sex, or just sex in general, we tend to drop Bayes like a hot potato and make out with Hume every time.

First date went well? We’re in love! No word for the next two days? He hates me! Got asked out in a clear, direct way? Hooray, a grown up! Got cancelled on a few days later? What a flake; it’s over. In relationships, we tend to ignore the past entirely in favor of how we are feeling right now (it’s raining today and thus will never be sunny again), OR deny the probable with the excuse that we can’t know for certain (sure, he hasn’t called for three weeks, but maybe he was unexpectedly sent to space; YOU don’t know). Either way, there is going to be a lot of anxiety and crying over what is – to be all cold and scientific for a second – just one new piece of data.

To be Bayesian in life, we must consider not just the newest information, but also the weight of everything else we have learned up to this point. This is easier than it sounds, but brace yourself: here comes the math. In Bayes’s theorem, when new information comes in (an event occurs), we must consider three specific things before we can make a probabilistic guess at the truth. Let’s make our “new event” one to which we can all relate: he asked for your number (email, Twitter handle, whatever), and then didn’t call (text, write, tweet, you get the idea). According to an entire franchise, this means without question that he is just not that into you. But to really judge the truth of that, Bayes asks us to evaluate the following:

First is the probability that, if it IS true – he is NOT into you – he would ask for your number and then not call. This is variable Y. It seems weird that someone not into you would ask for your info, so our instinct might initially be to set this probability low. But then again, there is social convention to consider, as well as alcohol, the existence of sadists, and the fact that this is Los Angeles where people are always hedging their bets, plus there is the actual fact of his not calling…so let’s say there is a 75% chance of someone NOT into you still asking for your info but then not calling. Y=0.75

Next we have to consider the opposite – the probability of someone who IS into you asking for your number but then not calling. This is variable Z. As a female, I can come up with a million possible reasons for the lack of call: maybe he lost my info, or his phone, or maybe he’s scared, or hasn’t broken up with his current girlfriend yet, or maybe he works for the CIA… But I am going to let the rational part of my brain step in and acknowledge that, while possible, all together there is still at most probably a 20% chance of any of these being true. Z=0.2

Finally, and most importantly, is what Bayesians refer to as the prior – the probability before the event, before knowing anything about this particular guy or situation, that any guy you meet would NOT be into you. This is variable X. This is also where self-esteem comes to play, so let’s start with a neutral 50%. X=0.5

Once you have assigned those probabilities, the math is pretty simple. The probability of it being true that his is, in fact, NOT into you is the fraction: (XY) over [(XY) + Z(1-X)]. In plain English, it is the probability of ANY guy being not into you multiplied by the probability of a guy being not into you and not calling (XY), divided by that product (XY) plus the probability of any guy being INTO you (1-X) multiplied by the probability of him being into you and not calling (Z). With our numbers, that is: (.5)(.75) / [(.5)(.75) + (.2)(.5)], which comes out to 0.79. So, yeah, there is an almost 80% chance he isn’t into you – but a far cry from the 100% chance that it feels like in the moment.

What I love most about this, though, is how it shows with math the effect that our own personal outlook changes the way we react to things (or should react to them). A person with very high self esteem would probably have a low prior – say, a 10% chance that any random guy would NOT be into her. When X gets changed from 0.5 to 0.1, the lack of phone call results in only a 29.5% chance that he isn’t that into you. We become more willing to consider the event a false positive. But if we have a low opinion of ourselves – say, a prior of 90% (and if this is you, listen to some Katy Perry or go hug a Muppet or something, stat) – one missing phone call results in a 97% chance he isn’t into you. Devastating. So, if you find yourself reeling from every little dating hiccup, take a hard look in the mirror and re-evaluate your priors. Also, find a friend to tell you how awesome you are – and listen.

Besides protecting us from the imbalanced impact of a false positive, Bayesian reasoning also defends against being that sucker who believes Adam Sandler could actually be a secret agent, because the idea is that we re-asses our reality with each event. Instead of treating each time he doesn’t call as a new event to be reasoned and given the benefit of the doubt in isolation, we absorb them and allow them to affect our prior. One last time, let’s set our variables: we will keep Y at 75% and Z and 20%, but let’s go for a normal, healthy prior of 30% – a 30% chance any random person wouldn’t be into you. When he doesn’t call the first time, this calculates out to a 61.6% chance he isn’t into you. This becomes our new prior for this guy (rounding down to 60% for the sake of headaches). Now, when we go out and run into this guy again, and he is flirty and attentive again, and then doesn’t call or communicate again (you know who you are), we calculate the probability that he isn’t into us with an X-factor (not to be confused with an American Idol) of 60%. That results in an 85% percent likelihood of his disinterest. And if it happens a third time (again, you know who you are, and I am NOT amused), the prior is set at 85% and Bayes’s theorem calculates a 95.5% chance he is not that into you. Time to write the boy off, for sure!

Bayesian reasoning allows us to learn and grow from experience, rather than repeat the same mistakes by coming at the world from a place of willful ignorance. Every failed relationship has something to teach us about what we do or don’t want in the future, until ideally we know enough to get one right. That is exactly the idea behind Bayes’s probabilistic thinking – it is the path, through logic, to less and less wrongness. We can’t ever be 100% certain about what is in another person’s heart or mind. But if we are willing to apply a little patience and, yes, math, we can get to a level of confidence that allows us to trust the gamble and win big.