"Update: A new, larger replication has contradicted the research described in this blog post. Click here for more information."
Many animals are known to adapt their bodies to influence other animals around them. Peacocks flare their feathers, chimpanzees inhale air to make their chests bulge, gazzelles stott - jumping higher than necessary when running away from a predator, cats run sideways when they are threatened to appear larger than they are. We all know humans do similar things for various reasons, but can the way we hold ourselves affect not just others' perceptions of us, but what is going on inside our own heads? In a series of experiments spanning many decades, psychologists exploring a field of research called embodied cognition have experimented by placing individuals in various positions under false pretences before examining how the position of the body might impact the way they think.
In 2010 social psychologist Amy Cuddy's landmark paper showed that getting people to pose in the pair of positions shown below (under the guise of attaching electrodes in different positions relative to the heart) resulted in increased levels of testosterone and reduced levels of the stress hormone cortisol. Her TED talk describing the experiment is now the second most popular TED talk of all time.
Testosterone rises before we engage in competition and following a win and falls following defeat, effectively reflecting and reinforcing an individual's dominance. Cortisol is associated with feelings of powerlessness, anxiety and negative health effects such as lowered immune function and weight gain. The participants who took on the powerful poses also reported feeling more "powerful" and "in charge".
Cuddy also discovered that the pair of weak poses shown below resulted in the reverse effect - increased levels of cortisol and decreased levels of testosterone. These results are supported by previous research that demonstrated that people placed in hunched postures were more likely to give up in a task that required persistence - a phenomenon known as learned helplessness. The people placed in hunched over positions also reported they felt more depressed, a finding that has been replicated repeatedly, including in Cuddy's study.
In Cuddy's 2010 study the participants who were placed in the weak poses with their arms crossed or in their laps were also more risk averse in a gambling game compared to those participants placed in a high power pose who were more willing to try to double their winnings by opting to roll a die.
In a classic study conducted in 1988, researchers got people to watch a cartoon while either holding a pen between their teeth, or between their lips without touching their teeth. Holding the pen between the teeth stimulated the same facial muscles used when we smile while biting with our lips alone makes it impossible to smile naturally. The researchers discovered that people found the cartoons funnier when they had the pen between their teeth. More recently, in a study that really makes you stop and think, researchers found that botox injections which can make it difficult to frown actually make people less depressed. Interestingly, the injections didn't make the people feel more attractive, suggesting the reduced feelings of sadness were not to do with the treatment's normal intended function. Amazingly, the results have recently been replicated in clinically depressed patients in a randomized, double-blind, placebo controlled trial. In the study published earlier this year over half of the depressed patients had at least a 50% reduction in a depression rating scale (compared to a 15% reduction in patients who received a placebo injection). 27% of the patients given botox even achieved clinical remission six weeks after the single treatment (in comparison to 7% of the patients in the placebo condition).
In a recently published study reminiscent of Monty Python's Ministry of Silly Walks sketch, psychologists manipulated people's walking patterns using a motion capture based biofeedback system. If the system detected an upright posture and swinging arms a gauge on a monitor would move in one direction. The participants weren't told what the gauge measured but were told to keep experimenting with different walking styles to move the gauge to the right. This allowed the participants to be manipulated to reflect either the characteristics of a depressed patient or a "particularly happy walking style". The researchers then asked the people to recall words from a list of happy or sad words. The overall results were unremarkable - the people who had been led to walk in a happy style remembered slightly more happy words and vice versa. But the people who had achieved the happiest walking style remembered three times as many of the positive words than the students who achieved the saddest style of walking.
In another study Amy Cuddy gave students a mock "dream job" interview in which they had five minutes to write and five minutes to deliver a speech to two interviewers. While preparing for the interview the students were asked to perform the "expansive" or "contractive" poses. The poses were not maintained during the interview - when the students could stand how they liked. During the interview the researchers who were dressed in white lab coats scribbled notes and withheld all emotions not giving so much as a smile or a nod. This procedure, known as the Trier Social Stress Test has been shown to result in a tsunami of cortisol, it is even believed to be the most ethical way to elicit the greatest amount of cortisol possible under laboratory conditions. The students who had held the expansive poses were rated higher in both the content and delivery of their speeches. Importantly, this was in spite of there being no statistically significant difference in their stances during the interview.
The findings of Cuddy's research aren't all rainbows and happiness however, in a series of experiments published last year Cuddy demonstrated that striking a "power pose" - the name Cuddy has given to particularly dominant stances - can make you more likely to act dishonestly. In the first experiment, people stretched for one minute in an expansive or contractive pose. Participants were told they would be paid $4 for participation but the experimenter then "accidentally" overpaid them, giving them $8 instead. Astoundingly, 78% of the people who were made to do the expansive pose kept the money compared to only 38% of those who were told to adopt the contractive pose.
In the next experiment people could earn money by unscrambling anagrams working only on either a small, or a large desk pad - surreptitiously forcing them to either spread their arms across the table or work in a hunched over fashion. The psychologists then gave the participants the answers and asked them to mark their own work - but unbeknownst to the participants a sheet of carbon paper was hidden under their worksheet. Those who worked on the small pad were more likely to cheat. In another experiment participants had to sit in a large comfortable seat or a small seat where they would feel squashed. They were told to stop for 10 seconds every time they crashed while playing a game of Need for Speed on the Playstation 3. The people who were in the seats that allowed them to take an expansive style of sitting were more likely to cheat. In a final study, that seems more interesting anecdotally than as evidence for the theory, Cuddy observed that drivers of cars with larger seats were more likely to double park in New York City, but this effect is clearly likely to be entangled with the fact that drivers who choose larger vehicles are likely to be very different types of people to those who would choose something more modest - but an interesting anecdote all the same, given that the experimenters were blinded, providing hard evidence for the belief that drivers of large cars tend to be less conscientious.
In another study Cuddy manipulated posture by providing participants with a task on either an iPod Touch, an iPad, a Macbook Pro or an iMac. The participants were told the experimenter would return after five minutes but the experimenter never returned. The researchers timed how long it would take for the participants to come looking for the absent experimenter. Amazingly the people who used the larger devices waited far less time before going looking for the experimenter - represented by the grey bars in the graph below. In fact only half of those who used the iPod Touch ever mustered up the courage to seek out the experimenter compared to nearly all of those who used the iMac - the percentages of participants who took the decision to look for the experimenter are represented by the dark grey bars in the graph below.
Exasperatingly - given their straight forward nature, Cuddy's findings have been widely misconstrued in the media. Cuddy's argument is that "power poses" should be used to help people prepare psychologically for a challenging social interaction, but crucially - not actually used in the social interaction itself. Maintaining a position that could be perceived as aggressive is not a pleasant way to engage with other human beings in most contexts. This is particularly important if you already have the dominant role in the relationship - for example if you are a manager or a doctor. It's been demonstrated for instance that doctors are more likely to be sued by their patients if they speak in tones rated as being more dominant. This was predicted from only forty seconds of speech that was scrambled to remove all meaning. That is not to say taking on a powerful stance is not useful for social interactions - just not every social interaction. Indeed, as Cuddy suggests, more often than not it may be best to push the table aside. Pitches, presentations, job interviews are all potential places Cuddy's techniques could be useful, but depending on the situation they may be best reserved for the bathroom. Obviously (you would think) the idea is not to put your feet on the table when conducting a job interview - as one of Cuddy's Harvard Business School students had the displeasure of actually witnessing - at Harvard Business School of all places.
The explosion of research in the field of embodied cognition over recent years appears to demonstrate that there is a very strong feedback loop between how we express our emotions with our bodies and how we experience our emotions, but the idea is not a new one. In 1872 Charles Darwin proposed that our facial expressions feed information back to our brain, altering our emotions positively or negatively. We all know how frustrating it is to be told to smile when we are having a bad day, but it seems there really is a good argument for reminding ourselves to smile, stand up tall, spread our shoulders wide and express positivity. We've known for a long time the importance of first impressions and the effect our body language can have on other people, but what we often forget - and what we're only recently seeing such strong evidence for, is the effect our body language can have on the inside.
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References:
Bos, Maarten W., and Amy J.C. Cuddy. "iPosture: The Size of Electronic Consumer Devices Affects Our Behavior."Harvard Business School Working Paper, No. 13-097, May 2013.
Cuddy, Amy J.C., Caroline A. Wilmuth, and Dana R. Carney. "Preparatory Power Posing Affects Performance and Outcomes in Social Evaluations." Harvard Business School Working Paper, No. 13-027, September 2012. (Revised November 2012.)
Carney D.R., Cuddy A.J.C. & Yap A.J. (2010). Power Posing: Brief Nonverbal Displays Affect Neuroendocrine Levels and Risk Tolerance, Psychological Science, 21 (10) 1363-1368. DOI: http://dx.doi.org/10.1177/0956797610383437
Finzi E. (2014). Treatment of depression with onabotulinumtoxinA: A randomized, double-blind, placebo controlled trial, Journal of Psychiatric Research, 52 1-6. DOI:http://dx.doi.org/10.1016/j.jpsychires.2013.11.006
Michalak J. & Nikolaus F. Troje (2015). How we walk affects what we remember: Gait modifications through biofeedback change negative affective memory bias, Journal of Behavior Therapy and Experimental Psychiatry, 46 121-125. DOI:http://dx.doi.org/10.1016/j.jbtep.2014.09.004
Riskind J.H. (1982). Physical posture: Could it have regulatory or feedback effects on motivation and emotion?, Motivation and Emotion, 6 (3) 273-298. DOI: http://dx.doi.org/10.1007/bf00992249
Strack F. & Sabine Stepper (1988). Inhibiting and facilitating conditions of the human smile: A nonobtrusive test of the facial feedback hypothesis., Journal of Personality and Social Psychology, 54 (5) 768-777. DOI: http://dx.doi.org/10.1037/0022-3514.54.5.768
Yap A.J., B. J. Lucas, A. J. C. Cuddy & D. R. Carney (2013). The Ergonomics of Dishonesty: The Effect of Incidental Posture on Stealing, Cheating, and Traffic Violations, Psychological Science, 24 (11) 2281-2289. DOI: http://dx.doi.org/10.1177/0956797613492425
Image Credits: Shutterstock, Tinypic, Cuddy et al. 2014, Cuddy et al. 2013
Our hearts beat at a resting rate of 60 to 100 beats per minute. Lots of other things pulse, too. The colors we see and the pitches we hear, for example, are due to the different wave frequencies ("pulses") of light and sound waves.
Now, a study in the journal Geoscience Frontiers finds that Earth itself has a pulse, with one "beat" every 27.5 million years. That's the rate at which major geological events have been occurring as far back as geologists can tell.
A planetary calendar has 10 dates in red
Credit: Jagoush / Adobe Stock
According to lead author and geologist Michael Rampino of New York University's Department of Biology, "Many geologists believe that geological events are random over time. But our study provides statistical evidence for a common cycle, suggesting that these geologic events are correlated and not random."
The new study is not the first time that there's been a suggestion of a planetary geologic cycle, but it's only with recent refinements in radioisotopic dating techniques that there's evidence supporting the theory. The authors of the study collected the latest, best dating for 89 known geologic events over the last 260 million years:
- 29 sea level fluctuations
- 12 marine extinctions
- 9 land-based extinctions
- 10 periods of low ocean oxygenation
- 13 gigantic flood basalt volcanic eruptions
- 8 changes in the rate of seafloor spread
- 8 times there were global pulsations in interplate magmatism
The dates provided the scientists a new timetable of Earth's geologic history.
Tick, tick, boom
Credit: New York University
Putting all the events together, the scientists performed a series of statistical analyses that revealed that events tend to cluster around 10 different dates, with peak activity occurring every 27.5 million years. Between the ten busy periods, the number of events dropped sharply, approaching zero.
Perhaps the most fascinating question that remains unanswered for now is exactly why this is happening. The authors of the study suggest two possibilities:
"The correlations and cyclicity seen in the geologic episodes may be entirely a function of global internal Earth dynamics affecting global tectonics and climate, but similar cycles in the Earth's orbit in the Solar System and in the Galaxy might be pacing these events. Whatever the origins of these cyclical episodes, their occurrences support the case for a largely periodic, coordinated, and intermittently catastrophic geologic record, which is quite different from the views held by most geologists."
Assuming the researchers' calculations are at least roughly correct — the authors note that different statistical formulas may result in further refinement of their conclusions — there's no need to worry that we're about to be thumped by another planetary heartbeat. The last occurred some seven million years ago, meaning the next won't happen for about another 20 million years.
When I was a junior in college, my electromagnetism professor had an awesome idea. Apart from the usual homework and exams, we were to give a seminar to the class on a topic of our choosing. The idea was to gauge which area of physics we would be interested in following professionally.
Professor Gilson Carneiro knew I was interested in cosmology and suggested a book by Nobel Prize Laureate Steven Weinberg: The First Three Minutes: A Modern View of the Origin of the Universe. I still have my original copy in Portuguese, from 1979, that emanates a musty tropical smell, sitting on my bookshelf side-by-side with the American version, a Bantam edition from 1979.
Inspired by Steven Weinberg
Books can change lives. They can illuminate the path ahead. In my case, there is no question that Weinberg's book blew my teenage mind. I decided, then and there, that I would become a cosmologist working on the physics of the early universe. The first three minutes of cosmic existence — what could be more exciting for a young physicist than trying to uncover the mystery of creation itself and the origin of the universe, matter, and stars? Weinberg quickly became my modern physics hero, the one I wanted to emulate professionally. Sadly, he passed away July 23rd, leaving a huge void for a generation of physicists.
What excited my young imagination was that science could actually make sense of the very early universe, meaning that theories could be validated and ideas could be tested against real data. Cosmology, as a science, only really took off after Einstein published his paper on the shape of the universe in 1917, two years after his groundbreaking paper on the theory of general relativity, the one explaining how we can interpret gravity as the curvature of spacetime. Matter doesn't "bend" time, but it affects how quickly it flows. (See last week's essay on what happens when you fall into a black hole).
The Big Bang Theory
For most of the 20th century, cosmology lived in the realm of theoretical speculation. One model proposed that the universe started from a small, hot, dense plasma billions of years ago and has been expanding ever since — the Big Bang model; another suggested that the cosmos stands still and that the changes astronomers see are mostly local — the steady state model.
Competing models are essential to science but so is data to help us discriminate among them. In the mid 1960s, a decisive discovery changed the game forever. Arno Penzias and Robert Wilson accidentally discovered the cosmic microwave background radiation (CMB), a fossil from the early universe predicted to exist by George Gamow, Ralph Alpher, and Robert Herman in their Big Bang model. (Alpher and Herman published a lovely account of the history here.) The CMB is a bath of microwave photons that permeates the whole of space, a remnant from the epoch when the first hydrogen atoms were forged, some 400,000 years after the bang.
The existence of the CMB was the smoking gun confirming the Big Bang model. From that moment on, a series of spectacular observatories and detectors, both on land and in space, have extracted huge amounts of information from the properties of the CMB, a bit like paleontologists that excavate the remains of dinosaurs and dig for more bones to get details of a past long gone.
How far back can we go?
Confirming the general outline of the Big Bang model changed our cosmic view. The universe, like you and me, has a history, a past waiting to be explored. How far back in time could we dig? Was there some ultimate wall we cannot pass?
Because matter gets hot as it gets squeezed, going back in time meant looking at matter and radiation at higher and higher temperatures. There is a simple relation that connects the age of the universe and its temperature, measured in terms of the temperature of photons (the particles of visible light and other forms of invisible radiation). The fun thing is that matter breaks down as the temperature increases. So, going back in time means looking at matter at more and more primitive states of organization. After the CMB formed 400,000 years after the bang, there were hydrogen atoms. Before, there weren't. The universe was filled with a primordial soup of particles: protons, neutrons, electrons, photons, and neutrinos, the ghostly particles that cross planets and people unscathed. Also, there were very light atomic nuclei, such as deuterium and tritium (both heavier cousins of hydrogen), helium, and lithium.
Cosmic alchemy
So, to study the universe after 400,000 years, we need to use atomic physics, at least until large clumps of matter aggregate due to gravity and start to collapse to form the first stars, a few millions of years after. What about earlier on? The cosmic history is broken down into chunks of time, each the realm of different kinds of physics. Before atoms form, all the way to about a second after the Big Bang, it's nuclear physics time. That's why Weinberg brilliantly titled his book The First Three Minutes. It is during the interval between one-hundredth of a second and three minutes that the light atomic nuclei (made of protons and neutrons) formed, a process called, with poetic flair, primordial nucleosynthesis. Protons collided with neutrons and, sometimes, stuck together due to the attractive strong nuclear force. Why did only a few light nuclei form then? Because the expansion of the universe made it hard for the particles to find each other.
What about the nuclei of heavier elements, like carbon, oxygen, calcium, gold? The answer is beautiful: all the elements of the periodic table after lithium were made and continue to be made in stars, the true cosmic alchemists. Hydrogen eventually becomes people if you wait long enough. At least in this universe.
In this article, we got all the way up to nucleosynthesis, the forging of the first atomic nuclei when the universe was a minute old. What about earlier on? How close to the beginning, to t = 0, can science get? Stay tuned, and we will continue next week.
To Steven Weinberg, with gratitude, for all that you taught us about the universe.
