You are a water-filled sack of flesh, your actions and decisions largely determined by the multiplicity of hormones, chemicals, and nutrients coursing through your body. And no, I’m not just talking about teenagers, with their “raging hormones.” I’m talking about you, a rational, reasonable, experienced, mature, highly organized, professional adult. You are at the mercy of your body, and you don’t even know it.

Don’t believe me? When’s the last time you ate some junk food just because it was there? Or skipped a workout? Or had another beer when you knew you shouldn’t? Most people are familiar with a lack of willpower in the context of exercise or diet – situations in which we know we’re doing something we’ll pay for later – but it also strikes in subtle ways that we mistake for intent.

Invasion of the Body Snatchers

Before we get to the meat of the post, let’s get extreme. There are plenty of gruesome examples from nature of parasites that hijack some aspect of their host’s cognitive function for their own nefarious ends. Just think about that – there you are, a perfectly normal ant, rat, fish, or person, and your mental state or actions are suddenly under the control of chemicals secreted by an invading parasite.

This can range from Ophiocordyceps unilateralis, a fungus that takes over an ant’s nervous system:

The ant falls from the tree where it normally lives, climbs on the stem of a plant, clamps its mandibles on a leaf and dies there, while the fungus consumes its tissues and grows outside it, releasing its spores.

To Euhaplorchis californiensis, which reproduce in the avian gut:

The cercariae latch onto the gills of the killifish and make their way along a nerve and into the brain cavity. The parasite forms a “carpet-like” layer over the brain. According to Lafferty, infected killifish are 4 times more likely to “shimmy, jerk, flash, and surface” than uninfected fish. This behavior makes the infected fish 30 times more likely to be caught and consumed by a bird.

To Taxoplasma gondii, which can only sexually reproduce within certain cats, and cause infected rats to stop fearing cat urine (emphasis added):

A number of studies have suggested subtle behavioral or personality changes may occur in infected humans, and infection with the parasite has recently been associated with a number of neurological disorders, particularly schizophrenia.

Wait, that was about humans, not rats. Seriously? Yeah, seriously. T. gondii is a foul little m***********.

So, why am I bringing these up? Am I suggesting that we’re all being controlled by tiny invaders? No, of course not. There are really two reasons – the first being to show extreme examples of chemically-induced mind control, and the second because they’re really freakin’ cool (hey, it’s my blog).

But enough about parasites with fancy Latin names. Let’s get down to the chemically-induced behavioral shifts that you – yes you – go through every day. I’m not talking about loss of inhibition due to alcohol or drugs – you know when you’re drunk, and even if you lose control, there should be no confusion about what’s going on, either on your part or on the part of those around you. I’m talking about normal life, and the choices you think you’re making, but that are actually being made for you by your biology.

Ego Depletion

Every day, there are lots of decisions to make. Big decisions, little decisions. Important decisions, irrelevant decisions. Cheerios or oatmeal? White shirt or blue? Highway or local roads? Work is one long series of decisions, each coming hard after another. Which questions to ask an interviewee? How to evaluate performance? Send an email, talk in person, or let an issue slide? Which code library to use? To whom to assign a task? Should you attend a meeting? What should you have for lunch? Which technical direction to take? How hard a line to take on a change request?

One after another, whether you realize it or not, you’re exhausting your mind’s ability to make decisions. As the day wears on, you either become reckless, sending that email you instantly regret, or more cautious, reverting to the status quo, becoming less willing to take chances. There’s a bit of a refresh after lunch, but then another rapid decline. Welcome to decision fatigue.

A fascinating New York Times Magazine article described a study done on Israeli judges. Amazingly, the most important determinant of whether an inmate was granted parole was the time of day of the hearing:

There was a pattern to the parole board’s decisions, but it wasn’t related to the men’s ethnic backgrounds, crimes or sentences. It was all about timing, as researchers discovered by analyzing more than 1,100 decisions over the course of a year. Judges, who would hear the prisoners’ appeals and then get advice from the other members of the board, approved parole in about a third of the cases, but the probability of being paroled fluctuated wildly throughout the day. Prisoners who appeared early in the morning received parole about 70 percent of the time, while those who appeared late in the day were paroled less than 10 percent of the time.

The key, it turns out, is glucose, and blood sugar level:

Again and again, the sugar restored willpower, but the artificial sweetener had no effect. The glucose would at least mitigate the ego depletion and sometimes completely reverse it. The restored willpower improved people’s self-control as well as the quality of their decisions: they resisted irrational bias when making choices, and when asked to make financial decisions, they were more likely to choose the better long-term strategy instead of going for a quick payoff.

It’s a fascinating article, and I recommend reading it in its entirety. But this blog is generally about technical management, and there are a couple of concrete lessons for us to take away.

1. You are what you eat

It’s a cruel joke – you need willpower to resist the munchies, but you need to snack to maintain willpower. Still, cruel or not, guarding against ego depletion throughout the day is key to a role that requires both decision-making and the ability to actively monitor one’s interpersonal interactions and mental state. As such, reducing the size of the main meals, and keeping a regular caloric intake throughout the day can improve your cognitive performance.

2. You are a morning person

Planning and prioritizing are among the most complex, important, ego depleting activities we engage in professionally. And yet we typically squander the most productive, cognitively capable time of the day on irrelevant decisions. Whether you believe it or not, you’re most productive in the morning. Don’t waste that energy! Don’t spend the first half hour going through email, making a hundred tiny decisions that could be deferred until later (delete, open, open, delete, reply, delete, delete, sigh, delete). Arrange your schedule so that you can make the most important decisions early in the day, and put off less important decisions until later. Making big decisions later in the day will end up costing you far more time to get to a worse result.

At this point, I know that a lot of you are thinking to yourselves that no, you aren’t morning people. After all, you do your best coding at 3 am! If you really are so sure, I’d simply ask you to take a moment to read the NY Times Magazine article, consider that your neurochemistry might not be so radically different from the rest of humanity, and decide whether you prefer science or magical thinking. Your call.

3. Lessons from Einstein, by way of David Cronenberg

In The Fly, Veronica (played by Geena Davis) notices that Seth (Jeff Goldblum) is wearing the same clothes as the day before (quote courtesy of IMDB):

The fewer decisions you have to make, the more ego you’ll have left for the choices you care about. As mentioned in the previous point, don’t waste your decision-making budget on things that don’t matter. Having a regular workout schedule (or class) will be easier than having a “three times a week” rule that requires you to choose whether or not to exercise every day. Creating filters that hide unimportant emails until the end of the day can dramatically improve your efficiency. Routinizing mundane tasks that you honestly don’t care about will help you conserve willpower for more important issues.

Final Word

Watching children grow up is fascinating, as you see them discovering the simplest truths about the world, things that you and I take for granted, one at a time. Blowing on hot soup cools it down. Putting your finger in front of a hose makes the water spray. Touching the little triangle makes the video play. But there’s no rule that says that getting to a certain age means that you know all of these simple truths. There are plenty out there still to discover.

The truth about our brains – that there’s a limit to the number of decisions we can make, that there’s an optimal time of day for making those decisions, and that we can recharge to some extent by eating – is a critical piece of understanding for improving our effectiveness. How will you rearrange your schedule to maximize your optimal decision-making time?

Further reading: Your Brain at Work is an excellent book that deals specifically with improving effectiveness through an understanding of your brain’s neurochemistry. Sounds complicated, but it doesn’t get too deep into the weeds. And SCARF (which the author covers in the second half of the book) is a useful model for thinking about interpersonal interactions.