_a group of people leaning over stuff_

Questions vs answers

Recently, I had a discussion with a friend about the key difference between science and engineering.

As a computer engineer, my friend found that the more advanced his coursework got and the more he learned about electronics, circuits, and microprocessors, the better he understood the subjects as a whole.

Which shouldn't be too surprising. That's the point of a college engineering degree: learn how stuff works and how to make stuff work.

But me, I find that as I learn more about brains and minds, filled with complex interactions between neurons, glial cells, neurotransmitters, and hormones, the picture gets steadily more complicated. The universe is one big dynamic system, full of chaotic pieces, and I keep finding more questions. The more I learn, the less I know.

That's the scientist's perspective on the world: more knowledge means more questions. More astonishment, more confusion.

(This is not a novel pronouncement, merely a recent observation supporting previously suggested differences between the two disciplines.)



I'm not one to make New Year's resolutions.

mean, sure, I could take my pick of popular New Year's resolutions; I could decide, on the first day of the new year, that this year, I'll start exercising more and eating better, or that I'll spend more time with my family and friends, or that I'll learn a new skill. And if I chose to make resolutions, I'd be far from alone--a 2008 survey on Dorthy.com found that 66% of the 2000+ adults polled had made resolutions at some point (though only 17% managed to keep them).

Making resolutions: It's about self-control

The question Anirban Mukhopadhyay of the Hong Kong University and Gita Venkatarmani Johar of the Graduate School of Business at Columbia University asked is this: What determines how many goals a person will set, and how successful a person will be at achieving those goals? They performed a few studies in 2005 to look at the relationship between self-control, goal setting, and goal achievement. They suggested that what you believe about self-control affects the goals you set and achieve [PDF].

In the paper, "self-control" is used to mean a sense of willpower. Mukhopadhyay & Venkatarmani discuss various lay theories of self-control, noting that the amount of self-control a person has can be seen as either an inherently limited or unlimited resource, and that this resource can be seen either as malleable or as fixed (the amount of self-control a person has can change over time, or not). An important premise to note here is the idea that the probability of choosing a goal or making a resolution increases if a person thinks that goal can be attained. So if you think you'll be able to achieve a goal, you're more likely to set it. Combine this with theories of self-control, and in general, if you believe you have unlimited stores of self-control, you'll set a larger number of goals. If you believe self-control is malleable but limited, you'll set fewer goals.

Mukhopadhyay & Venkatarmani also discuss self-efficacy: belief in one's capabilities, the perceived ability to carry out a desired action. They propose that people with high self-efficacy--people who believe that failure is the result of insufficient effort, and thus exhibit increased commitment and persistence--will achieve more of their goals than people with low self-efficacy, who tend to view failure as the result of deficient ability, and thus may simply give up.

The studies

In the first study, 85 participants (all college students) each read one of four passages presenting lay theories of self-control. Each passage contained two paragraphs; the first discussed self-control either as limited or as unlimited, and the second discussed self-control as either malleable or fixed. The participants then answered questions about their belief in each of two theories presented, followed by a second questionnaire to assess motivation, in which they listed all their current goals.

The study was testing whether a belief in unlimited, malleable self-control would result in most resolutions, and indeed, this is what was found. The experimenters had some concerns about participants' natural beliefs in relation to the passages they read, however, so in study two, the order of the two measures (lay theories and motivation/goal listing) was varied. Data from 130 new participants revealed that, as hypothesized, if the motivation & goals questionnaire were assessed first, then among the people who believed self-control is malleable, those who also believed self-control to be unlimited (vs. limited) set more goals. When lay theories were assessed first, this result reversed. The people who believed that self-control is fixed were unaffected by order.

The third study moved on to examine goal achievement, adding a measure to look at self-efficacy. The study had two sessions, in November then February. In the first session , the 159 participants read passages about lay theories (much like in study one, but with longer passages to strengthen the manipulation), listed the resolutions they were planning on making at New Years, rated how disappointed they would be if they failed to keep their resolutions, and filled out individual difference measures (which included a self-efficacy scale). Only 86 participants successfully returned for the second session, during which they indicated how much success they had had at keeping their resolutions.

What does this mean for your resolutions?

The resolutions made by participants across all conditions were qualitatively similar (take a look at any list of popular New Year's resolutions, and you'll see the majority of the goals). As shown in the first two studies, more goals were set by people who believe self-control is unlimited and malleable than by any other people--that is, if you expect more success, you may increase the difficulty and number of tasks that you set for yourself. Self-efficacy did not have a significant effect on goal-setting.

As far as success goes, only the interaction between lay theory and self-efficacy was significant. If participants believed in limited self-control and were low in self-efficacy, they tended to give up more often, failing to achieve their goals. But if participants believed in unlimited self-control, self-efficacy had no effect; participants achieved just as many goals regardless, and people who set more resolutions were marginally more likely to succeed.

Mukhopadhyay & Venkatarmani realize that their research does not directly look at the relationship between lay theories of self-control and beliefs about one's own amount of self-control and self-efficacy, and propose this as an area for future study. But in general, lay theories about self-control can determine how much success you'll expect (and thus, how many goals you'll set), and self-efficacy beliefs can determine how much success you'll actually have.


Mukhopadhyay, A. & Johar, G.V. (2005). Where There Is a Will, Is There a Way? Effects of Lay Theories of Self-Control on Setting and Keeping Resolutions. Journal of Consumer Research, 31, 779-786 [PDF]


The longest Monday of my life

I recently returned to the US from Australia. The 14-hour flight took me from Monday morning in Sydney to Monday morning, again, in L.A. Crossing the date line messed up my sense of time enough without the added bonus of thinking I should be heading to bed just as the sun began to climb into the California sky.

You may be familiar with the concept: Jet lag. The catch-all name for circadian misalignment, the disruption of sleep cycles and circadian rhythms. If you've had the pleasure of crossing time zones in a jet plane, whether it was a mere three-hour hop from one coast of the US to the other or a trip to another continent, chances are, you've experienced some amount of jet lag.

The pathophysiology of jet lag

Normally, two systems--the homeostatic system and the circadian system--work together to produce a 24-hour sleep cycle. During the day, the homeostatic system slowly accumulates a 'sleep drive,' a desire to sleep that increases as a function of time spent awake. The circadian system generates an alerting signal in opposition to this sleep drive, which, during the day, keeps a person from feeling increasingly sleepy. An hour or two before bedtime, this signal subsides, and s/he realizes it's time to hit the pillow. The sleep drive dissipates as a person sleeps and by morning (assuming a full night's rest and possibly some coffee), s/he will be feeling alert and ready to go again.

Robert Sack wrote a delightful paper [PDF] on jet lag, by the way, which is where I'm getting much of my information.

So we've got a nice cycle of sleep. Jet lag is what happens when the homeostatic and circadian processes are misaligned. For example, the circadian system may signal a person to be alert when it's not actually morning, or may be reduced during daytime hours, causing daytime sleepiness because the homeostatic sleep drive is no longer cancelled out.

But I don't want to be sleepy!

How do you beat jet lag? Robert Sack lists three primary approaches:

  1. Reset the body clock
  2. Prescribed sleep scheduling
  3. Medication to counteract daytime sleepiness or insomnia

Let's start with the first one, as it turns out to be the most complicated.

Resetting the body clock

The two most effective ways to reset the body clock are 1) through bright light exposure, and 2) timed melatonin administration. (But see the end of this post: fasting can also reset the body clock.)

Light is one of the most important cues about time of day and has the greatest effect on circadian timing (much smaller effects are seen from regular activities and meals, for example). Studies have shown that without light cues, totally blind people tend to have free-running circadian rhythms with an average period of 24.5 hours, instead of the usual 24. If a person is exposed to bright light early in the day, the person's internal clock is reset to an earlier time; if exposure is instead in the evening, the internal clock is reset to a later time. Brighter light has more of an effect (such as the sun, at 3000 to 10,000 lux), though lower intensities (e.g., 100-550 lux) can produce changes.

Artificial light sources can be used to supplement daylight, to help reset a person's internal clock to the correct new time zone when traveling. Alternatively, a person could wear very dark glasses, as light avoidance could help minimize the problems of light exposure at the wrong time of day or night.

Resetting the body clock, Part 2: Melatonin

Melatonin is a hormone that has been linked to the regulation of circadian rhythms and sleep cycles [PDF]. Melatonin is secreted by the pineal gland at night; secretion is suppressed by light exposure, and as such, the hormone can be thought of as a "darkness signal." If doses of melatonin are administered in the morning, circadian rhythms will be shifted later; evening doses shift rhythms earlier. Timing of the doses is more important than amount per dose, though it remains to be seen what the optimal dose and optimal time of administration is--trials have been done with doses from 0.5 to 10mg, at times ranging from three days before departure to five days after arrival in the new time zone.

If doses of melatonin are combined with light exposure, the results are what you might expect: synergistic if both are administered to produce a time shift in the same direction (both earlier or both later); antagonistic otherwise.

Sleep, wake, sleep, wake

The second way to beat jet lag: Sleep at weird times. Slowly adjust your sleep schedule to match that of your destination, or keep your home sleep schedule for a while after you arrive. The problem with this is that your sleep-wake schedule won't match up with that of the people around you, and if you need to be awake for breakfast at 7am or for a meeting in the afternoon, your sleep schedule may interfere. Use this method at your own risk.

Drugs for everything

Lastly, we have sleep medicines. As you might guess, hypnotic medications combat insomnia and stimulants fight off daytime sleepiness pretty well, because by definition, that's what they do. Both benzodiazepine and non-benzodiazepine drugs have been shown to be effective in the first case; for the latter, the most common solution is to consume more coffee [PDF]. This works! In the study linked, subjects were treated with slow-release caffeine or with melatonin prior to a long eastward flight; the caffeine subjects were less sleepy than either melatonin or placebo. Granted, caffeine subjects also took longer to fall asleep later and awoke more frequently, but that may be a risk you have to take.

Lagging behind

Light, melatonin, drugs, strange sleep schedules. Of course, the only solution that will always work is time. The homeostatic and circadian processes need to realign, and while the aforementioned ways of beating jet lag can fast track the process, it still takes time.

UPDATE: I was alerted by a friend of the existence further research of which I was unaware: Another way to reset your sleep-wake cycle is to stop eating. If you fast for about 12 to 16 hours, your body clock will reset, with whatever time you break your fast as morning. The Fuller, Lu, & Saper paper [PDF], published in Science, discusses the mechanism, though a more recent paper argues that the Fuller et al. results are inconclusive.


We're in the dark

Recent measurements of the cosmic microwave background (radiation leftover from the universe's early hot and dense state) support the hypothesis that dark matter and dark energy make up 95% of everything in existence.

But what's the matter?

Isn't it fascinating and mind-boggling that we have almost no idea what the majority of the stuff in our universe is? There are dark matter and dark energy are not rather than explain what these mysterious stuffs are. E.g., dark matter is not just dark clouds of normal matter (called baryonic matter); it is not antimatter; it is not huge black holes. But it is 25% of the universe.

Current research on dark energy hasn't faired better: Is it a property of space, as suggested by Einstein's cosmological constant? Perhaps it's a result of the quantum mechanics of space; maybe it's a new kind of energy field. It's also possible that Einstein was wrong. It wouldn't be the first time a seemingly brilliant solution, explaining everything known at the time, was later replaced. Think "ether." Think "animal spirits." Think "caloric fluid." That said, there's nothing better to replace it yet. At least this time we're acknowledging the fact that the names "dark energy" and "dark matter" refer to stuff we don't yet understand.

The quest goes on

The Joint Dark Energy Mission, a space probe designed to study dark energy, has been in the works for a while now. The mission is currently in a tight spot as NASA, the Department of Energy, and the European Space Agency tussle over who's in charge of which parts of the probe and who's paying for what. Don't you love international politics? A lot of people, such as the folks at the Cosmic Variance blog are up in arms about the disagreements--can't we all just get along and do science?