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Limits of Control

Do you ever get the feeling that you’re “running low” on self-control?

Nom nom nom. Willpower fail.

Like attention, self-control seems to be a limited resource in a connectome. In fact, these may not be two separate entities at all, but aspects of a single mental resource, which we might call volition, or perhaps willpower. Many experiments have shown that the more self-control a person exerts – especially over an extended period of time – the less attention they can devote to subsequent cognitive demands, like solving puzzles or taking initiative.

This might seem like an obvious fact, but what’s really fascinating is the variety of ways in which it can play out.

Here’s one example, from an article on a 1998 study by Baumeister et al.

[The researchers] had food-deprived subjects sit at a table with two types of food on it: cookies and chocolates; and radishes. Some of the subjects were instructed to eat radishes and resist the sweets, and afterwards all were put to work on unsolvable geometric puzzles. Resisting the sweets, independent of mood, made participants give up more than twice as quickly on the geometric puzzles. Resisting temptation, the researchers found, seemed to have “produced a ‘psychic1 cost.’”

In short, a person can only make so many difficult decisions in a limited period of time, before he or she becomes mentally sapped and falls back on instinctual reactions. These mental resources appear to be crucial for a heterogeneous range of behaviors, from resisting a snack to solving a puzzle to tolerating annoying noises. As Wan et al. put it in their 2011 paper, “exerting self-control leads to a temporary depletion of regulatory resources, which in turn influences subsequent self-control behaviors.”

Wan et al. bring up the concept of construal levels to help explain this. The basic idea is this: our connectomes conceptualize rewards and punishments at several levels of abstraction, such as (in roughly ascending order of abstraction) immediate pleasure or pain, delayed gratification, concepts like “healthy” or “beautiful,” and ideals like “fair” or “worthwhile.” The more abstract and/or delayed a reward (or punishment) is, the more mental resources we need in order to be effectively motivated by it.

Here’s a practical example: after a day of mentally exhausting work, we’re more likely to choose a tasty meal than a healthy one. In other words, the more attention we’ve devoted to one task (or type of task), the less reasoning power is available for the next one – until we give our brains some rest and replenishment. This is true even if the types of tasks are completely unrelated.

One common “cure” for low energy and wandering attention is caffeine, but this chemical works less like an energy paycheck and more like a credit card – the boost it gives you now will only lead to higher mental debt in the long run. To understand how this works, let’s take a closer look at the neuropharmacology of caffeine.

Caffeine’s molecular shape mimics that of adenosine, a chemical that forms the “spine” of several larger molecules crucial for transporting energy around cells, such as adenosine triphosphate (ATP). Now, cells throughout the body (including neurons in the brain) have receptors specifically shaped to accept adenosine – you can think of the receptor as a molecular lock in the cell membrane, and adenosine as that lock’s key.

Adenosine, passing energy around in a cell's metabolism.

What caffeine does is latch onto cells’ adenosine receptors, acting as a receptor antagonist – in other words, it tricks the cells into thinking they’re full up on adenosine, which means there’s plenty of energy left. This triggers a cascade of physiological changes: sleepiness is suppressed, “excitement” chemicals like dopamine and epinephrine (a.k.a. adrenaline) are released, and you get a boost of energy.

But your connectome will eventually get wise to the lack of adenosine, and will close down the party. This is why a cup of coffee can keep you alert for a little while, but these benefits come at the cost of a shortened attention span and less patience – and often an unpleasant crash in the afternoon (which also has a lot to do with caffeine’s appetite-suppressing effects).

Like any other drug, caffeine induces artificial modifications of chemical systems evolved for specific purposes. There’s not necessarily anything harmful about that, but it’s also not a very effective long-term solution.

Still, there are a few hacks that can help you make the most of the attentional resources at your disposal. One of my favorites is to make a list, prioritized not necessarily in order of importance, but in descending order of willpower required – and interweaving small and immediate rewards along the way.

For instance, if it’s difficult to motivate yourself to hit the gym, you might make that your top priority as soon as you leave work or school – and follow it up with a little snack from your favorite restaurant. This keeps your mind focused on the reward, and teaches you to associate that reward with the volition-draining task. This is just basic associative (Hebbian) learning, but when you combine that technique with a list of tasks in descending order of willpower needed, you can often amaze yourself with how much you accomplish.

The flip side of this coin is the importance of keeping tabs on your remaining willpower, and being realistic about how much strength you have left. Just as you might decrease your running speed to finish the last few miles of a marathon, you may need to put off some arduous tasks until you’re more rested. This is where it’s crucial to learn the difference between lack of motivation and genuine mental exhaustion. Forcing yourself to perform when you lack the necessary resources tends to result in inferior performance – and will make you more susceptible to other temptations throughout the day.

By teaching yourself to gauge your own willpower, developing a clear sense of which tasks will require the most, and rewarding yourself for accomplishing those tasks, you’ll soon rocket to surprising new levels of productivity. I know because I’ve done it.


1. The word “psychic” doesn’t carry any paranormal connotation here; it just means “psychological,” as it did in the early 20th century. Why Baumeister et al. didn’t use a more modern scientific term is anybody’s guess. Throughout the rest of the paper, they use the term “executive function,” which makes more sense; but for this post, I’m largely sticking with “volition” and “willpower.”

Sharing Thoughtspace

A couple posts back, I asked what you thought it’d be like to not have a self. Today, I want to ask a related question with a very different set of implications.

Exactly where are the boundaries of your self?

Maybe you’d say its limits are defined by the physical boundaries of your nervous system. On the other hand, you might define the boundaries of your self more abstractly, and identify them with the limits of your assembled sensory perceptions, feelings, and thoughts.

I choose to imagine that the robot in the thought experiment looks like this.

The tricky thing is, no matter how we try to define those boundaries, philosophers have come up with some mind-bending thought experiments to explore their logical consequences.

Here’s an example. Imagine that in the near future, scientists design a robot that can be remotely controlled by thought alone (this isn’t very farfetched at all, actually). Let’s say the robot is equipped with senses of sight and sound – and by wearing a special virtual reality helmet, you see (in ultra-HD) what the robot’s eye-cameras see, and hear the sounds its audio sensors pick up. Furthermore, wherever your thoughts direct the robot to go, it goes. When you think “turn around,” it instantly obeys.

It’s not hard to imagine that, after an hour or so of wearing the special VR helmet, you’d get the distinct impression that you were somehow in the robot. Your body would still be seated in a chair or reclining on the bed, of course – but where would your self be?

When I say “self,” I’m not talking about the traditional concept of a soul, but something more abstract – the unnamed sense that enables you to distinguish between “a hand” and “my hand;” and to know where you end and another person begins.

In fact, in I Am a Strange Loop, Douglas Hofstadter brings up the idea that in a long-term intimate relationship, it can become difficult to distinguish your preferences and ideas – and sometimes even memories – from the other person’s. In a sense, both of you begin to “think with another person’s brain,” to use Hofstadter’s phrase – or, one might say that both of your selves, to some degree, are represented throughout both brains. It can be blissful or catastrophic, depending on the situation.

This is all a bit abstract, but let’s take a look at a more down-to-earth example. Last week, I was fascinated to read this story of 4-year-old twins with a conjoined brain. Conjoined twins are rare enough as it is, and ones with craniopagus (i.e., who are conjoined at the head) are even rarer – but these particular twins seem to be unique in all of medical history:

Their brain images reveal what looks like an attenuated line stretching between their two brains – a piece of anatomy their neurosurgeon, Douglas Cochrane of British Columbia Children’s Hospital, has called a thalamic bridge, because he believes it links the thalamus of one girl to the thalamus of her sister.

The twins, thinking some deep twin thoughts.

As I’ve mentioned before, the thalamus acts as a relay station for signals entering the brain from the peripheral nervous system – and it also forms a critical part of the thalamo-cortico-thalamic circuits that enable the cerebral cortex to process and respond to sensory data. In short, some doctors think these twins may share – and even actively participate in – each others’ subjective sensory experiences. One might say they’re “experiential roommates” in a way none of us will ever be.

Though the story admits that no controlled clinical trials of the girls’ behavior or neurophysiology have been conducted (their family is understandably wary), anecdotal evidence suggests that the twins exhibit an extraordinary level of nonverbal coordination. Here are some examples:

Krista reached for a cup with a straw in the corner of the crib. “I am drinking really, really, really, really fast,” she announced and started to power-slurp her juice, her face screwed up with the effort.

Tatiana was, as always, sitting beside her but not looking at her, and suddenly her eyes went wide. She put her hand right below her sternum, and then she uttered one small word that suggested a world of possibility: “Whoa!”

“Now I do it,” Tatiana said, reaching for the cup from which her sister was just drinking. She started to chug. Krista’s hand flew to her own stomach. “Whoa!” she said.

“I have two pieces of paper,” Krista announced.

The girls sat at a small table in the living room, drawing, their faces, as always, angled away from each other. Each had one piece of paper. So I was surprised by Krista’s certainty: She had two pieces of paper?

“Yeah,” the girls affirmed in their frequent singsong unison, nodding together.

On the rare occasions when the girls fight, it’s painful to watch: they reach their fingers into each other’s mouths and eyes, scratching, slapping, hands simultaneously flying to their own cheeks to soothe the pain.

Without hard neurological data, it’s hard to speculate in detail about what to make of all this. But one thing seems clear: although the twins have distinct personalities, motivations and preferences, a large amount of their sensory experience is shared – through nonverbal communication and perhaps even direct CNS connections. Reading the story, one gets the sense that the girls’ developing senses-of-self are struggling to define themselves amid a sea of shared perceptions – possibly even shared thoughts. I can’t resist bringing up Hofstadter’s famous “Twinwirld” thought experiment:

[In Twinwirld], instead of people normally giving birth to one person, the normal birth, in fact almost all births, are identical twins. And so the identical twins grow up just basically hanging around together all the time, and they become what I call a ‘pairson’. And they’re two halves; they have the same name, so not even Greta and Freda, but just the same name, but if you want you can append an ‘l’ and an ‘r’, you can call that a left and a right if you want to them.

So here is Karen for example. Karen consists of two pieces, Karen L and Karen R. And here is another ‘pairson’, Greg L and Greg R. And Karen and Greg get married and they have ‘twildren’, Lucas and Natalie. Lucas is a boys and Natalie is a girls. And this is totally normal. This is the way it is in twinworld, and Lucas considers himself to be one thing; he does know that he has two parts, but he doesn’t feel as if he’s divided in two.

This guy's mind is just all over the place.

When I first read about Twinwirld, it seemed like a very strange fantasy. But after reading about the real twins – Krista and Tatiana – it seems that the only really implausible part is the idea that two human minds (i.e., a “pairson”) could ever have completely identical tastes and motivations. But then again, maybe the two halves of a pairson would have debates and fights, just as we all sometimes furiously debate within our own minds – and just as the twin girls occasionally escalate their arguments to physical violence. Bodily limitations aside, it’s not so implausible to conceive of a whole society composed of such pairs.

The fact that a human mind can still develop at all in such an unorthodox environment as the twin girls’ mind(s?) is – I think – a ringing endorsement of the human connectome’s versatility. But most of us are “wired” with a sense of ourselves that assumes a discrete, bounded, and spatially contiguous container for that self: “One Self, One Brain, One Body.” And this message is subtly reaffirmed at every level of human interaction, from the verbal to the societal.

Are these boundaries as sharp as we assume they are, though? In certain situations, such as the relationship example above, another person’s brain can help us think our thoughts – and even form a major part of our self-identity. Some of us may live to see a level of technology that challenges the necessity of a direct correlation between self and body. And as the twins‘ story shows, those ideas may not apply in every case even today.

So, next time you find yourself engrossed in a live video feed of a place in another city, or notice that you’re finishing your best friend’s sentences, you might try asking yourself where, exactly, your self is located. I’ll leave you with a little song for thinking about this.

Sexy Neuroscience

Q. Would you like to hear about a study that involves the keywords “fMRI” and “orgasms?”

A. Yes. Yes you would.

fMRI images of a woman's brain throughout an orgasm.

A team of neuroscientists at Rutgers are working to unravel the neurophysiological correlates of female sexual arousal and climax. What they’re finding, intriguingly enough, is (gasp!) that creativity and empathy are just as crucial to a woman’s sexual pleasure as physical stimulation is – and maybe even moreso. Explicit sexual fantasizing activates most of the same brain regions as an equivalent series of physical touches. “More than 30 areas of the brain are active during the event,” one article says, “including those involved in touch, memory, reward – and even pain.”

Those activation patterns become more intense when an actual physical stimulus is introduced. The one oddball, though, is the prefrontal cortex (PFC), a region of the frontal lobe that’s crucial to tasks like attention switching and imagining oneself in another person’s place. And what exactly the PFC does during orgasm is the subject of a Science Mystery right now. The Rutgers team think they’ve discovered that the PFC becomes more active during orgasm, whether it’s achieved through physical touch or thought alone (yep, there are people who can think themselves to orgasm). Meanwhile, a team at the University of Groningen in the Netherlands think they’ve discovered something else: in their experiments, the PFC evidently “shuts off” during orgasm – especially a region of the PFC called the orbitofrontal cortex (OFC), which is involved in the process of self-control.

This has led the Netherlands team to describe an orgasm as an “altered state of consciousness.” As the lead researcher on the project says:

I don’t think orgasm turns off consciousness but it changes it. When you ask people how they perceive their orgasm, they describe a feeling of a loss of control. I’m not sure if this altered state is necessary to achieve more pleasure or is just some side effect.

Well, here’s an important distinction. 1) The orgasmic altered state itself may not be necessary from a purely reproductive standpoint (I’ll come back to this), but 2) the mental side of sex is deeply intertwined with the physical one, and both need to work together properly if anyone’s going to have much fun. This ties in with a topic I’ve written about before: that fascinating intersection between abstract representation and physiological response.

But wait! As it turns out, these two teams of researchers may have unwittingly stumbled on two different roads to orgasm:

It is possible there is a difference between someone trying to mentalise sexual stimulation as opposed to receiving it from a partner. … Perhaps having a partner makes it easier to let go of that control and achieve orgasm. Alternatively, having a partner may make top-down control of sensation and pleasure less necessary to climax.

These alternate perception modes have intrigued me for a long time, though this is the first time I’ve seen them brought up in this context. But the point the article makes is a great one: with a little practice, it becomes surprisingly easy to shift back and forth between task-positivity and introspection. And in fact, the article goes on to talk about orgasm research as a learnable mode of conscious pain modulation:

Orgasm is a special case of consciousness. If we can look at different ways of inducing orgasm, we may better understand how we can use top-down processing to control what we physically feel.

Cool stuff. But what about this orgasmic altered state – this hidden place of Zen-like concentration and/or ego-dissolving nirvana? Why does it seem to be available in several different “flavors?” What about its strange behavior: it’s at least partly dependent on conscious control, and can be be consciously suppressed, but it’s impossible to initiate instantly at will (I don’t mean “instantly” like “in a minute or so,” but “instantly” in the sense of “as instantly as you can picture your favorite color, or feel upset“)?

Some delicious physical touch.

It’d be easy to lazily explain this by saying that orgasms are designed by natural selection to be as addictive as possible, while requiring some threshold to prevent false alarms and premature embarrassments. But it’s not always helpful to reason backwards from fortuitous end results – it’d be just as easy (and pointless) to say that the sun is 93 million miles from the Earth because that’s the perfect distance for producing Earth-like environments. Doesn’t really explain much about the original causes, or about how things might have worked if they’d been different.

So, coming soon in the exciting world of sexual neuroscience, we’ll hopefully start to see some new data about these various types of orgasms, and why evolution wired us to experience such unusual altered states. Addictive “reward” chemicals may be straightforward enough, but an orgasm is much more than just a dopamine rush. Just what it is, exactly, will be fun to find out.

Magical Mice

Before I get into the magic mice, I should probably explain about the magic ravens.

Even if you don’t follow the old Nordic religion of Asatru, you’ve probably heard about the one-eyed god Odin (maybe from Thor or Sandman comics, both of which are epically fun to read). Rack your connectome a little, and you might remember that Odin had two super-intelligent ravens, Huginn and Muninn* (Thought and Memory). While Odin chilled on his throne in Valhalla, Huginn and Muninn would fly around the world, then return to tell him everything they saw.

Odin chillin' with Huginn and Muninn, evidently making some kind of medieval Trollface.

I think the stories about Huginn and Muninn are trying to explain that thought and memory seem almost magical, when you stop to think about it. Do they just fly around each other in endless strange loops, or are they reporting back to something else…?

It’s questions like these that keep neuroscientists (and philosophers, and nerds like me) up at night. That’s why I do a happy dance whenever I read about research like this, because it means I get to learn a learn a little more about how memory works.

It breaks down a little sum’n like this: a research team at Princeton have genetically engineered mice with ultra-powerful memories. These furry little dudes can coast through the AP honors program in Mouse School (which seems, mainly, to involve a lot of Not Getting Lost in Confusing Places) in about half the time it takes an average mouse. One of these rodent geniuses – the star of the program, you might say – is a mouse named (seriously) “Doogie.” He can solve complex mazes in a flash, and he remembers his previous solutions effortlessly. A Sudoku addiction clearly lies in his future.

To show why this particular article gets me all hot ‘n’ bothered, I’m gonna quote a quote that was quoted in another quote:

“There’s something magical about taking a mind and making it work better,” says Alcino Silva, a professor of neuroscience at the University of California, Los Angeles and one of the pioneers of the enhanced cognition field. “In neuroscience, we’ve learned so much from loss-of-function mutants. But we’re only beginning to learn from these smart animals.”

Meanwhile, the smart animals continue to study the scientists, watching and plotting…always plotting…

If that's a raven, this may be a depiction of the ultimate animal super-team.

There’s a clear upshot to all this mouse engineering: the more scientists learn to isolate genes related to memory and learning, the brighter the light at the end of the tunnel for people suffering from dyslexia, ADHD, and a slew of other mental troubles.

And that’s only the beginning. I mean, imagine what it’d be like to have a truly perfect memory…to always be able to find the word that’s on the tip of your tongue… to never forget where you left your keys… to never forget anything… Ohhh wait; this is headed into Cautionary Tale of Hubris territory now, isn’t it?

Yep. Because it raises the question of what, exactly, a “deficit” in memory is. You don’t need me to tell you that there are some things we’d all rather forget. I mean, one of my very favorite movies is about that exact need. So you kinda have to feel some sympathy for the mouse described here:

When placed in an enclosure where days before it had received a mild electric shock – a jolt so minor, most mice don’t even react to it – this mouse cowers in the corner frozen with fear. Its enhanced memory is both blessing and burden.

So, basically, he has lifelong post-traumatic stress. How delightful.

The article also mentions a medical case that really got me thinking (or maybe remembering).

Sherashevsky had such a perfect memory that he often struggled to forget irrelevant details. For instance, [he] was almost entirely unable to grasp metaphors, since his mind was so fixated on particulars.

…which sounds a little weird, until you think about the last time you tried to explain a joke that your audience just didn’t “get.” The more you explain the details, the less funny the joke becomes – the more the humor seems to vanish behind the words. Here’s where it gets absolutely mind-blowingly fascinating (for me, anyway):

Other researchers have used computer models of memory to demonstrate that memory is actually optimized by slight imperfections, which allow us to see connections between different but related events. “The brain appears to have made a compromise in that having a more accurate memory interferes with the ability to generalize,” Farah says. “You need a little noise in order to be able to think abstractly, to get beyond the concrete and literal.”

So, in short, we need to forget some of what we experience in order to think about what we’ve experienced. Even a magical mouse needs to forget in order to learn.

Now, if he could just get that other mouse named “Pinky” to stop asking him so many inane questions…


*On a random tangent, I realized that the word “Muninn” sounds almost exactly like the first word of the Iliad, Μῆνιν (“rage”…or “of rage” if you’re gonna get all grammatical). Anyway, I found this so completely awesome that my hands spontaneously typed this footnote, then burst into flames.

Other researchers have used computer models of memory to demonstrate that memory is actually optimized by slight imperfections, which allow us to see connections between different but related events. “The brain appears to have made a compromise in that having a more accurate memory interferes with the ability to generalize,” Farah says. “You need a little noise in order to be able to think abstractly, to get beyond the concrete and literal.”

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