Time’s Arrow Traced to Quantum Source - Entanglement (via Quanta Magazine)

This is an interesting article on the role of quantum entanglement in creating equilibrium in systems. This is very physics-y. Like this:

Using an obscure approach to quantum mechanics that treated units of information as its basic building blocks, Lloyd spent several years studying the evolution of particles in terms of shuffling 1s and 0s. He found that as the particles became increasingly entangled with one another, the information that originally described them (a “1” for clockwise spin and a “0” for counterclockwise, for example) would shift to describe the system of entangled particles as a whole. It was as though the particles gradually lost their individual autonomy and became pawns of the collective state. Eventually, the correlations contained all the information, and the individual particles contained none. At that point, Lloyd discovered, particles arrived at a state of equilibrium, and their states stopped changing, like coffee that has cooled to room temperature.

If you can get through that paragraph, you'll have no problem with the whole article - and it's worth the read!

Time’s Arrow Traced to Quantum Source

Cups of coffee cool, buildings crumble and stars fizzle out, physicists say, because of a strange quantum effect called “entanglement.”

By: Natalie Wolchover
April 16, 2014


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Coffee cools, buildings crumble, eggs break and stars fizzle out in a universe that seems destined to degrade into a state of uniform drabness known as thermal equilibrium. The astronomer-philosopher Sir Arthur Eddington in 1927 cited the gradual dispersal of energy as evidence of an irreversible “arrow of time.”

But to the bafflement of generations of physicists, the arrow of time does not seem to follow from the underlying laws of physics, which work the same going forward in time as in reverse. By those laws, it seemed that if someone knew the paths of all the particles in the universe and flipped them around, energy would accumulate rather than disperse: Tepid coffee would spontaneously heat up, buildings would rise from their rubble and sunlight would slink back into the sun.

“In classical physics, we were struggling,” said Sandu Popescu, a professor of physics at the University of Bristol in the United Kingdom. “If I knew more, could I reverse the event, put together all the molecules of the egg that broke? Why am I relevant?”

Surely, he said, time’s arrow is not steered by human ignorance. And yet, since the birth of thermodynamics in the 1850s, the only known approach for calculating the spread of energy was to formulate statistical distributions of the unknown trajectories of particles, and show that, over time, the ignorance smeared things out.

Now, physicists are unmasking a more fundamental source for the arrow of time: Energy disperses and objects equilibrate, they say, because of the way elementary particles become intertwined when they interact — a strange effect called “quantum entanglement.”

“Finally, we can understand why a cup of coffee equilibrates in a room,” said Tony Short, a quantum physicist at Bristol. “Entanglement builds up between the state of the coffee cup and the state of the room.”


Courtesy of Tony Short
A watershed paper by Noah Linden, left, Sandu Popescu, Tony Short and Andreas Winter (not pictured) in 2009 showed that entanglement causes objects to evolve toward equilibrium. The generality of the proof is “extraordinarily surprising,” Popescu says. “The fact that a system reaches equilibrium is universal.” The paper triggered further research on the role of entanglement in directing the arrow of time.

Popescu, Short and their colleagues Noah Linden and Andreas Winter reported the discovery in the journal Physical Review E in 2009, arguing that objects reach equilibrium, or a state of uniform energy distribution, within an infinite amount of time by becoming quantum mechanically entangled with their surroundings. Similar results by Peter Reimann of the University of Bielefeld in Germany appeared several months earlier in Physical Review Letters. Short and a collaborator strengthened the argument in 2012 by showing that entanglement causes equilibration within a finite time. And, in work that was posted on the scientific preprint site arXiv.org in February, two separate groups have taken the next step, calculating that most physical systems equilibrate rapidly, on time scales proportional to their size. “To show that it’s relevant to our actual physical world, the processes have to be happening on reasonable time scales,” Short said.

The tendency of coffee — and everything else — to reach equilibrium is “very intuitive,” said Nicolas Brunner, a quantum physicist at the University of Geneva. “But when it comes to explaining why it happens, this is the first time it has been derived on firm grounds by considering a microscopic theory.”

If the new line of research is correct, then the story of time’s arrow begins with the quantum mechanical idea that, deep down, nature is inherently uncertain. An elementary particle lacks definite physical properties and is defined only by probabilities of being in various states. For example, at a particular moment, a particle might have a 50 percent chance of spinning clockwise and a 50 percent chance of spinning counterclockwise. An experimentally tested theorem by the Northern Irish physicist John Bell says there is no “true” state of the particle; the probabilities are the only reality that can be ascribed to it.

Quantum uncertainty then gives rise to entanglement, the putative source of the arrow of time.

When two particles interact, they can no longer even be described by their own, independently evolving probabilities, called “pure states.” Instead, they become entangled components of a more complicated probability distribution that describes both particles together. It might dictate, for example, that the particles spin in opposite directions. The system as a whole is in a pure state, but the state of each individual particle is “mixed” with that of its acquaintance. The two could travel light-years apart, and the spin of each would remain correlated with that of the other, a feature Albert Einstein famously described as “spooky action at a distance.”

“Entanglement is in some sense the essence of quantum mechanics,” or the laws governing interactions on the subatomic scale, Brunner said. The phenomenon underlies quantum computing, quantum cryptography and quantum teleportation.


Courtesy of Seth Lloyd
Seth Lloyd, now an MIT professor, came up with the idea that entanglement might explain the arrow of time while he was in graduate school at Cambridge University in the 1980s.

The idea that entanglement might explain the arrow of time first occurred to Seth Lloyd about 30 years ago, when he was a 23-year-old philosophy graduate student at Cambridge University with a Harvard physics degree. Lloyd realized that quantum uncertainty, and the way it spreads as particles become increasingly entangled, could replace human uncertainty in the old classical proofs as the true source of the arrow of time.

Using an obscure approach to quantum mechanics that treated units of information as its basic building blocks, Lloyd spent several years studying the evolution of particles in terms of shuffling 1s and 0s. He found that as the particles became increasingly entangled with one another, the information that originally described them (a “1” for clockwise spin and a “0” for counterclockwise, for example) would shift to describe the system of entangled particles as a whole. It was as though the particles gradually lost their individual autonomy and became pawns of the collective state. Eventually, the correlations contained all the information, and the individual particles contained none. At that point, Lloyd discovered, particles arrived at a state of equilibrium, and their states stopped changing, like coffee that has cooled to room temperature.

“What’s really going on is things are becoming more correlated with each other,” Lloyd recalls realizing. “The arrow of time is an arrow of increasing correlations.”

The idea, presented in his 1988 doctoral thesis, fell on deaf ears. When he submitted it to a journal, he was told that there was “no physics in this paper.” Quantum information theory “was profoundly unpopular” at the time, Lloyd said, and questions about time’s arrow “were for crackpots and Nobel laureates who have gone soft in the head.” he remembers one physicist telling him.

“I was darn close to driving a taxicab,” Lloyd said.

Advances in quantum computing have since turned quantum information theory into one of the most active branches of physics. Lloyd is now a professor at the Massachusetts Institute of Technology, recognized as one of the founders of the discipline, and his overlooked idea has resurfaced in a stronger form in the hands of the Bristol physicists. The newer proofs are more general, researchers say, and hold for virtually any quantum system.

“When Lloyd proposed the idea in his thesis, the world was not ready,” said Renato Renner, head of the Institute for Theoretical Physics at ETH Zurich. “No one understood it. Sometimes you have to have the idea at the right time.”

Lidia del Rio
As a hot cup of coffee equilibrates with the surrounding air, coffee particles (white) and air particles (brown) interact and become entangled mixtures of brown and white states. After some time, most of the particles in the coffee are correlated with air particles; the coffee has reached thermal equilibrium.

In 2009, the Bristol group’s proof resonated with quantum information theorists, opening up new uses for their techniques. It showed that as objects interact with their surroundings — as the particles in a cup of coffee collide with the air, for example — information about their properties “leaks out and becomes smeared over the entire environment,” Popescu explained. This local information loss causes the state of the coffee to stagnate even as the pure state of the entire room continues to evolve. Except for rare, random fluctuations, he said, “its state stops changing in time.”

Consequently, a tepid cup of coffee does not spontaneously warm up. In principle, as the pure state of the room evolves, the coffee could suddenly become unmixed from the air and enter a pure state of its own. But there are so many more mixed states than pure states available to the coffee that this practically never happens — one would have to outlive the universe to witness it. This statistical unlikelihood gives time’s arrow the appearance of irreversibility. “Essentially entanglement opens a very large space for you,” Popescu said. “It’s like you are at the park and you start next to the gate, far from equilibrium. Then you enter and you have this enormous place and you get lost in it. And you never come back to the gate.”

In the new story of the arrow of time, it is the loss of information through quantum entanglement, rather than a subjective lack of human knowledge, that drives a cup of coffee into equilibrium with the surrounding room. The room eventually equilibrates with the outside environment, and the environment drifts even more slowly toward equilibrium with the rest of the universe. The giants of 19th century thermodynamics viewed this process as a gradual dispersal of energy that increases the overall entropy, or disorder, of the universe. Today, Lloyd, Popescu and others in their field see the arrow of time differently. In their view, information becomes increasingly diffuse, but it never disappears completely. So, they assert, although entropy increases locally, the overall entropy of the universe stays constant at zero.

“The universe as a whole is in a pure state,” Lloyd said. “But individual pieces of it, because they are entangled with the rest of the universe, are in mixtures.”

One aspect of time’s arrow remains unsolved. “There is nothing in these works to say why you started at the gate,” Popescu said, referring to the park analogy. “In other words, they don’t explain why the initial state of the universe was far from equilibrium.” He said this is a question about the nature of the Big Bang.

Despite the recent progress in calculating equilibration time scales, the new approach has yet to make headway as a tool for parsing the thermodynamic properties of specific things, like coffee, glass or exotic states of matter. (Several traditional thermodynamicists reported being only vaguely aware of the new approach.) “The thing is to find the criteria for which things behave like window glass and which things behave like a cup of tea,” Renner said. “I would see the new papers as a step in this direction, but much more needs to be done.”

Some researchers expressed doubt that this abstract approach to thermodynamics will ever be up to the task of addressing the “hard nitty-gritty of how specific observables behave,” as Lloyd put it. But the conceptual advance and new mathematical formalism is already helping researchers address theoretical questions about thermodynamics, such as the fundamental limits of quantum computers and even the ultimate fate of the universe.

“We’ve been thinking more and more about what we can do with quantum machines,” said Paul Skrzypczyk of the Institute of Photonic Sciences in Barcelona. “Given that a system is not yet at equilibrium, we want to get work out of it. How much useful work can we extract? How can I intervene to do something interesting?”

Sean Carroll, a theoretical cosmologist at the California Institute of Technology, is employing the new formalism in his latest work on time’s arrow in cosmology. “I’m interested in the ultra-long-term fate of cosmological space-times,” said Carroll, author of “From Eternity to Here: The Quest for the Ultimate Theory of Time.” “That’s a situation where we don’t really know all of the relevant laws of physics, so it makes sense to think on a very abstract level, which is why I found this basic quantum-mechanical treatment useful.”

Twenty-six years after Lloyd’s big idea about time’s arrow fell flat, he is pleased to be witnessing its rise and has been applying the ideas in recent work on the black hole information paradox. “I think now the consensus would be that there is physics in this,” he said.

Not to mention a bit of philosophy.

According to the scientists, our ability to remember the past but not the future, another historically confounding manifestation of time’s arrow, can also be understood as a buildup of correlations between interacting particles. When you read a message on a piece of paper, your brain becomes correlated with it through the photons that reach your eyes. Only from that moment on will you be capable of remembering what the message says. As Lloyd put it: “The present can be defined by the process of becoming correlated with our surroundings.”

The backdrop for the steady growth of entanglement throughout the universe is, of course, time itself. The physicists stress that despite great advances in understanding how changes in time occur, they have made no progress in uncovering the nature of time itself or why it seems different (both perceptually and in the equations of quantum mechanics) than the three dimensions of space. Popescu calls this “one of the greatest unknowns in physics.”

“We can discuss the fact that an hour ago, our brains were in a state that was correlated with fewer things,” he said. “But our perception that time is flowing — that is a different matter altogether. Most probably, we will need a further revolution in physics that will tell us about that.”

This article was reprinted on Wired.com.

Ravens Are Aware of Peers' Social Ranks

Another cool study on ravens has been released, this one published at Nature Communications, and it's open access - yay science!

Anyone who has observed ravens knows they are highly social animals. They will often mate for life (with a little polyamory among friends), and they occasionally gather in large groups to share, well, something - the days events, dudes in caveman masks who must be attacked, or good places for food, only the raven knows.

So new research indicates - singularly among birds - that ravens are aware of and remembers the social status of other ravens, even those not in their family or social group.

They found that ravens paid especial attention and seemed stressed -- displaying behaviors like head turns and body shakes -- when they hear playbacks that simulate a rank reversal in their group. They just didn’t expect a low-ranking bird to show off to a higher-ranking one -- this violates their rank relations. They were fine when the dominance structure in the playback reflects their hierarchy accurately.

The ravens also became agitated  in response to simulated rank reversals in neighboring groups, which the researchers assume to mean that ravens know who’s the alpha among unknown birds just by watching and listening to them (since there was no physical contact between groups). This is the first evidence that animals can track social rank of individuals that are not a part of their own group. 

The first article below is a summary from I Fucking Love Science, and the second is the full research article from Nature Communications.

Ravens Keep Track of Others' Ranks

April 24, 2014 | by Janet Fang
I Fucking Love Science

Two ravens nurturing their good relationship by preening each other.
Photo credit: Jorg Massen

Ravens are political animals. They can distinguish different sorts of interactions between other ravens, then alter their behavior accordingly. Like humans and other mammals, ravens not only understand, but also keep track of third party relationships. They’re the first bird known to do so.

In certain social organizations and dominance hierarchies, the key to survival is social intelligence and an understanding of community dynamics. Not only do you need to know who’s nice and who’s not to get by on a daily basis, but for every political maneuver, it’s important to know who will support whom.

To investigate this in these big brained birds, a team led by Jorg Massen from the University of Vienna, Austria, recorded audio files that contain vocal interactions between ravens and played them for a group of 16 captive ravens (Corvus corax).

They found that ravens paid especial attention and seemed stressed -- displaying behaviors like head turns and body shakes -- when they hear playbacks that simulate a rank reversal in their group. They just didn’t expect a low-ranking bird to show off to a higher-ranking one -- this violates their rank relations. They were fine when the dominance structure in the playback reflects their hierarchy accurately.

The ravens also responded to simulated rank reversals in neighboring groups, suggesting that they’ve figured out who’s boss among unknown birds just by watching and listening to them (since there was no physical contact between groups). It’s the first evidence of animals tracking rank relations of individuals that don’t belong to their own group -- a useful skill for a bird switching foraging units.

Last week, we learned about cuckoos using mafia tactics, and here’s another metaphor for you. "When Tony Blundetto made fun about Tony Soprano, as spectators of the show, we immediately recognized that this was inappropriate with regard to the dominance order within the Soprano family,” Massen says in a news release. “We make this inference not by comparing our own rank relation with the two Tony's with each other, but instead we have a mental representation of the rank relation of the two that gets violated in the turn of these events."

The findings suggest that complex cognitive abilities evolved multiple times in species as distantly related as ravens and human, solving similar social issues.

The work was published in Nature Communications this week.
[University of Vienna via Los Angeles Times]
Images: Jorg Massen

* * * * * * * * * *

Full Citation:
Massen, J. J. M. et al. (2014, Apr  22). Ravens notice dominance reversals among conspecifics within and outside their social group. Nat. Commun. 5:3679 doi: 10.1038/ncomms4679 

Ravens notice dominance reversals among conspecifics within and outside their social group

Jorg J. M. Massen, Andrius Pašukonis, Judith Schmidt & Thomas Bugnyar

Abstract

A core feature of social intelligence is the understanding of third-party relations, which has been experimentally demonstrated in primates. Whether other social animals also have this capacity, and whether they can use this capacity flexibly to, for example, also assess the relations of neighbouring conspecifics, remains unknown. Here we show that ravens react differently to playbacks of dominance interactions that either confirm or violate the current rank hierarchy of members in their own social group and of ravens in a neighbouring group. Therefore, ravens understand third-party relations and may deduce those not only via physical interactions but also by observation.

Introduction

The ‘social brain hypothesis’ (SBH)1, 2, 3 attributes the evolution of intelligence to the cognitive demands of social life. In support of the SBH, measures of social complexity and/or competence are found to correlate with neocortex size3 and reproductive success4, 5, 6. Furthermore, the type and quality of social relationships turns out to play a key role in several vertebrate societies, irrespective of group stability and the degree of fission–fusion dynamics7, 8, 9, 10. Species living with long-term pair partners, for instance, tend to have bigger brains than those forming short-term or seasonal relations11, 12. The exceptions are primates, possibly because their social life requires them to deal not only with one but several long-term relationships at a time3. Indeed, primates, not only recognize others as kin, friend or dominant but also understand third-party relationships within these kin-, friendship- and/or dominance networks13, 14, 15, 16, 17. A similar picture has been discussed for spotted hyenas, which live under social conditions comparable to primates18.

Recently, the SBH has been extended to birds19 and used to explain the apparent case of convergent evolution of intelligence in apes and corvids20. However, evidence that birds have an understanding of social dynamics similar to that of mammals is still scarce. For example, although several bird species seem to be capable of transitive inference21, 22, 23, 24, 25 (but see ref. 26), only two species have been experimentally tested for using this capacity to predict their own dominance status compared with that of a stranger27, 28. Note that these inferences are based on recent events, that is, seeing others winning or losing against a known individual, and do not necessary require knowledge about the relationship between the other individuals. The experiments clearly show, however, that the birds readily used the experience they had with one of the combatants from previous encounters. In the studies on primates and hyenas, the classification of relative rank relations also concerned group members they had ample interactions with in daily life28. It thus remains unknown whether non-human animals can deduce social relations such as relative rank between individuals they can observe but not interact with themselves.

As the largest and most widely distributed member of the corvid family, ravens are renowned for their relatively big brains and high behavioural and ecological flexibility29. Their cognitive skills are expressed primarily in the social domain: on one hand, they flexibly switch between group foraging (including active recruitment)30 and individual strategies (like providing no or false information about food, attributing perception and knowledge states about food caches to others)31; on the other hand, they form and maintain affiliate social relations aside from reproduction and engage in primate-like social strategies like support during conflicts32, and reconciliation and consolation after conflicts33. Understanding social relations of others may be key in those behaviours. Ravens also remember former group members and their relationship valence over years34, which might be important for life in non-breeder flocks where some individuals stay together over extended periods of time, whereas others do not35. A consequence of these dynamics is that ravens regularly meet conspecifics of different degrees of familiarity, many of which they have never interacted with before. As dominance rank heavily depends on affiliation status and social support by others35, raven non-breeders are ideal to test for the ability of third-party understanding between birds that regularly interact but also of those that know each other merely by observation. Therefore, here we tested 16 captive common ravens, Corvus corax, on their ability to recognize third-party rank relations of individuals they regularly interact with (group members) and those they do not (neighbouring group) by use of a playback experiment applying an expectancy violation paradigm5.

In this study we show that ravens react differently to playbacks of expected and unexpected dominance interactions of conspecifics. Consequently, ravens seem to understand third-party rank relations. As they do so, both of individuals within their own group as well as of individuals in a neighbouring group, we suggest that ravens are capable of forming representations of others’ relationships that are entirely based on observation of other’s interactions.

Results

Playbacks of group members

The final generalized linear mixed models (GLMM’s) on the delta-scores of in-group playbacks showed that ravens became more stressed and showed more self-directed behaviour when the playback violated their expectancy of rank relations compared with playbacks of expected interaction, since the models revealed a significant effect of treatment (expected versus unexpected) on self-directed behaviour (GLMM: F=7.09, df1=1, df2=57, P=0.010; Fig. 1a) and a similar, yet non-significant trend for ‘stress’ behaviour (GLMM: F=3.93, df1=1, df2=57, P=0.052; Fig. 1b).

Figure 1: Self-directed and ‘stress’ behaviour in response to in-group stimuli.

Mean±s.e.m. difference between playback and baseline (delta: Δ) of (a) self-directed behaviour and (b) ‘Stress’ behaviour, for playbacks simulating expected (purple bars) and unexpected (orange bars) dominance interactions of in-group individuals. For clarity, we added 2 to these means. n=16, GLMM: *P<0.05, #0.05<P<0.10.

In addition, the models showed an interaction effect between the sex of the subject and condition on self-directed behaviour (GLMM: interaction sex × condition: F=5.49, df1=1, df2=57, P=0.023; Fig. 2), suggesting that the main effect of condition is mainly due to the females. Post hoc analyses indeed revealed that females reacted with significantly more self-directed behaviour after an unexpected playback compared with an expected playback (Wilcoxon-signed ranks test: T+=44, n=9, P=0.011), whereas for males this difference was non-significant (Fig. 2). Furthermore, the models showed that compared to baseline, individuals became more active when their expectancy was violated, yet only when it concerned playbacks of their own sex (GLMM: interaction sex−combination × condition: F=6.65, df1=1, df2=57, P=0.013; Fig. 3). Post hoc analyses confirmed that individuals became significantly more active when they heard an unexpected playback compared with an expected playback of their own sex (Wilcoxon-signed ranks test: T+=123, n=16, P=0.004), whereas this difference was non-significant when the playback concerned individuals of the other sex (Fig. 3). Finally, we found significant effects of age on the components activity (GLMM: F=9.401, df1=1, df2=57, P=0.003), attention (GLMM: F=4.34, df1=1, df2=57, P=0.042) and ‘stress’ (GLMM: F=4.71, df1=1, df2=57, P=0.034), indicating that compared to baseline, older individuals reacted with more activity, less interest and more stress to playbacks in general, regardless of their congruence (Supplementary Fig. 1).

Figure 2: Sex differences in self-directed behaviour in response to in-group stimuli.

Mean±s.e.m. difference between playback and baseline (Δ) self-directed behaviour of males (n=7) and females (n=9), for playbacks simulating expected (purple bars) and unexpected (orange bars) dominance interactions of in-group individuals. For clarity, we added 2 to these means. GLMM and post hoc Wilcoxon-signed ranks tests: *P<0.05.

Figure 3: Activity in response to in-group stimuli of the same or of the other sex.

Mean±s.e.m. difference between playback and baseline (Δ) of activity, for playbacks simulating expected (purple bars) and unexpected (orange bars) dominance interactions of in-group individuals of the same sex and of individuals of the different sex. For clarity, we added 2 to these means. n=16, GLMM and post hoc Wilcoxon-signed ranks tests: *P<0.05; **P<0.01.

Playbacks of neighbouring group

Regarding the playbacks of out-group conspecifics, we found no main effect of treatment on the behaviour of the ravens. However, we did find significant interaction effects of the sex of the subject with treatment on vocalization (GLMM: interaction sex−combination × condition: F=4.28, df1=1, df2=57, P=0.043) and on attention: (GLMM: interaction sex−combination × condition: F=4.05, df1=1, df2=57, P=0.049), suggesting that only males respond to violations of rank relations of out-group conspecifics. Compared with baseline, males reduced their vocalizations when the playback violated their expectancy of rank relations significantly more than during playbacks of expected interaction (Wilcoxon-signed ranks test: T+=26, n=7, P=0.043), whereas for females this difference was non-significant (Fig. 4a). Similarly, males tended to reduce their behaviours indicative of showing attention compared with baseline more when the playback was unexpected than when it was expected (Wilcoxon-signed ranks test: T+=24, n=7, P=0.091), whereas for females there was no such trend (Fig. 4b). Finally, we found significant effects of the sex of the playbacked individuals on attention (GLMM: F=10.84, df1=1, df2=57, P=0.002) and self-directed behaviour (GLMM: F=5.23, df1=1, df2=57, P=0.026), suggesting that compared to baseline, individuals reacted with more interest, and less stress release to playbacks of same sex individuals in general, regardless of their congruence (Supplementary Fig. 2).

Figure 4: Vocalizations and close interest behaviour of males and females in response to out-group stimuli.

Mean±s.e.m. difference between playback and baseline (Δ) of (a) vocalizations and (b) close interest behaviour of males (n=7) and females (n=9), for playbacks simulating expected (purple bars) and unexpected (orange bars) dominance interactions of in-group individuals. For clarity, we added 2 to these means. GLMM and post hoc Wilcoxon-signed ranks tests: *P<0.05, #0.05<P<0.10.

Discussion

Our results reveal that ravens show different behaviour after playbacks that simulate a rank reversal in their group in comparison with playbacks that suggest dominance interactions in line with the current dominance hierarchy. These findings demonstrate that ravens, just like primates13, 14, 15, 16, 17, can distinguish these different types of playbacks and thus have some knowledge about the rank relations of their group members. Furthermore, male ravens responded to playbacks violating the dominance relations of their neighbouring group. This is, to our knowledge, the first experimental demonstration that non-human animals may recognize the rank relations of out-group members. Moreover, these findings strongly suggest that ravens are capable of forming representations of others’ relationships that are entirely based on observation of other’s interactions. Owing to our controlled captive set-up, we can exclude that subjects had any experience of physically interacting with members of the neighbouring group before testing. Hence, the subjects’ own ranks were independent of the ranks of the out-group members being played back, and the rank relations of out-group members could not be deduced through comparison of the absolute rank differences between the played back individuals and the tested individual (that is, the focal subject’s own rank relative to those of others).

A prevailing criticism on similar playback experiments in primates is that individuals just react more strongly to distress/submissive calls from more dominant individuals as these occur less frequently. However, out of 12 individuals used to combine the stimuli, we only included one top-ranking bird that only recently before the study became the dominant male in its group. Moreover, the ranks of the individuals that produced the submissive call in our playbacks could not significantly predict any of the response variables in both the in- and the out-group condition, respectively (GLMM: P>0.05). Thus, the effect cannot be explained by simple habituation to the submissive calls of lower-ranking birds.

Furthermore, the different response patterns to in- and out-group members indicate that the played back stimuli were meaningful to the birds. All ravens tended to react with an increase in ‘stress’ behaviour, and particularly females reacted with an increase in self-directed behaviours, which often correlates with the reduction of stress36, 37, to simulated rank reversals in their own group. Furthermore, all ravens increased activity levels when the simulated rank reversal was about members of their own sex, that is, when it concerned the position close to their own in the rank hierarchy. Consequently, (simulated) rank reversals in their own group seem stressful for ravens, especially when these reversals happen in positions close to your own rank (same sex) or when you are low in the dominance rank hierarchy (females35, 38). In contrast, when the playback concerned simulated rank reversals in the neighbouring group, they showed no signs of stress or activity but a change in vocalization and attention. Interestingly, they decreased these behaviours during violations, suggesting that they were prone to display interest to simulated interactions of known rather than unknown outcome. This corresponds to the observations that ravens are excellent in monitoring, and actively intervening, in status-related interactions of other ravens34 and the findings of previous playback experiments that ravens show a stronger vocal response to familiar than to unfamiliar conspecifics34. A sophisticated use of bystander information has also been found in the context of food caching, including judging the others’ perspectives and possibly even knowledge sates31.

Aside studies on transitive inference21, 22, 23, 24, 25, 27, 28, the current study provides the first experimental test for third-party knowledge in birds that is based on an expectancy violation paradigm as used in mammals5; yet our results fit well to the selectivity in third-party interventions of corvids observed under daily life conditions12, 32 and to the increase in heart rate measured in bystanders of third-party interactions in free-ranging graylag geese39. Taken together, these findings support the hypothesis that understanding the relationships between others is critical for navigating in a complex social world not only in mammals but also in birds. Interestingly, the social life of most birds with its relatively high degree of fission–fusion dynamics over seasons and years35 is quite different from that of the well-studied primates like baboons and vervet monkeys, which live in relatively stable groups40. Yet, social bonds and pairbond-like friendships are highly important in corvids and the other avian species of interest11, 12, creating a system of dependent ranks. This is especially true for female ravens, which substantially gain in rank by bonding to males35. The crucial role of males in raven society for gaining and maintaining status might be the reason why only males responded to simulated rank reversals in the out-group condition of our experiment. Future studies may show whether females do not know about these relations or just did not show a response in this set-up. On the basis of the current results, we argue that both male and female ravens understand the third-party rank relations of those individuals they regularly interact with (their own group), and that by mere observation male ravens also seem to have a representation of the rank relations of the members of a neighbouring group.

Methods

Subjects and housing

We used 16 sub-adult captive ravens housed in two separate social groups of eight birds each at the Haidlhof Research Station, Bad Vöslau, Austria. Both groups contained male and female peers (group 1: 3 males, 5 females; group 2: 4 males, 4 females). For a description of each individual (for example, age, rank and raising history) see Supplementary Table 1. Both groups were kept in adjacent parts of a large aviary complex (compartment A and B; Fig. 5a) for 9 months, with full visual and auditory access to the other group. Before the experiments, during a 1-month period, each group was trained to temporarily use another part of the complex, that is, birds of group 1, that traditionally were found in part B, could move to part C; birds of group 2, that traditionally used part A, could move to part B when group 1 was in C (Fig. 5b). This procedure allowed us to familiarize birds of both groups with the middle compartment B, which was subsequently used for testing. All aviary parts are enriched with trees, perches, playing devices and shallow pools for bathing. The middle compartment B is subdivided into two same-sized parts (B-I, B-II) by wire mesh panels with sliding doors and an opaque observation hut (2.5 × 2.5 m2). On experimental days, the birds received their normal diet consisting of meat, milk products, bread, vegetables and fruits twice a day. Water was available ad libitum.

Figure 5: Schematic representation of the set-up of the aviaries.

Aviaries A (18 × 10 × 5 m3), B (15 × 15 × 5 m3) and C (8 × 10 × 5 m3), housing group 1 (orange) and group 2 (yellow) during the different phases (a–c) of the experiment. The black dot represents an example of an animal in a test, the sound logo the place of the speaker from which the playback was played and the camera logo the respective place of the cameras that filmed this bird.

Ethical note
The ravens of group 1 originated from captive breeding pairs in zoos (Alpenzoo Innsbruck, Austria; Zoo Wels, Austria; and Nationalpark Bayrischer Wald, Germany) and a private owner (K Trella, Austria); those of group 2 originated from captive breeding pairs at the Konrad Lorenz Forschungsstelle in Grünau, Austria and from Lund University, Sweden. The study complied with Austrian law and local government guidelines (§ 2. Federal Law Gazette number 501/1989), and received oversight from the internal behavioural research group at the faculty of Life sciences, University of Vienna, and was authorized owing to its non-invasive character. The study subjects remained in captivity at Haidlhof Research Station after the completion of this study for further research.

Experimental design and set-up

Experiments started after all birds were comfortable with a short individual separation in the middle compartment B, while their conspecifics remained in parts A and C. For testing, the focal subject was called either into subdivision B-I or B-II, that is, in the half being closer to A or C, respectively; the loudspeaker used for playing back the stimuli was hidden in the opposite subdivision, always behind the wooden hut. Specifically, the loudspeakers’ position was such that the direction of the played back stimuli was congruent with the current position of the group that particular stimuli could come from: if the focal subject was positioned in B-I, it was tested with stimuli of group 1 from the direction of C; if it was positioned in B-II, it was tested with stimuli of group 2 from the direction of A (Fig. 5c).

Each playback contained three vocal interactions of the same individuals, each separated by 1 min. Stimuli were played from a loudspeaker (LD systems Roadboy 65, flat frequency response 80–15 kHz) connected to a MacBook Pro through a wireless system (Sennheiser EK 2000, flat frequency response 25–20 kHz). Loudness was adjusted to the natural submissive vocalization sound pressure levels. The actual playback loudness at the receiver varied depending on focal bird’s position in the aviary and the weather conditions. To hinder social learning and/or disruption of established hierarchies, the test playbacks were masked for all other animals using synchronized white-noise playbacks from two loudspeakers (LD systems Roadboy 65, flat frequency response 80–15 kHz), one directed at each groups. All loudspeakers were visually occluded for all animals.

Conditions

Focal individuals were subjected to playbacks of vocal interactions (see acoustic information below) of two other birds in an order consistent with the group’s dominance hierarchy (expected condition) and in an order inconsistent (that is, mimicking a rank reversal) with the group’s dominance hierarchy (unexpected condition). Per testing day, the birds received two sessions: one with playbacks of individuals of their own sex and one with playbacks of individuals of the different sex. In addition, animals were tested twice: once with playbacks of group members (both males and females) and once with playbacks of members of the other group (again both males and females). Consequently, all birds were tested in four conditions per in/out-group; that is, two control (expected) and two corresponding test (unexpected) conditions. The order of expected versus unexpected was counterbalanced over the tested birds within each session, the order of the played back sexes was counterbalanced over the tested birds over the two sessions per day and the order of in- or out-group playbacks were counterbalanced over the tested birds over the two testing days. For a schematic representation of all conditions please see Supplementary Table 2.

Testing lasted roughly an hour per day: after a 15-min habituation period, we played back the first stimulus to the subject (session 1, for example, own sex/congruent), and after another 15 min, we played back the second stimuli (session 2, for example, own sex/incongruent), followed by 15 min post observations. For the entire period, the behaviour of the focal subject was videotaped (using two Canon LEGRIA HD-camcorders). Models (that is, those individuals whose calls were played back) remained the same per focal subject, that is, both the expected and unexpected playback of either familiar (in-group) or unfamiliar (out-group) and of either same-sexed and different-sexed birds. For an overview of which models were used for which subject, please see Supplementary Table 1.

Acoustic recordings and stimuli preparation

The playback consisted of two types of vocalizations: self-aggrandizing display (hereafter SAD) and submissive calls41. Ravens of both sexes show SADs accompanied by a dominant posture, as a directed dominance display, which is often followed by submissive calls (Supplementary Fig. 3), and submissive posture and retreat by the subordinate individual. Note that the combination of SADs and submissive calls determined the meaning of the interaction, that is, a mild conflict with clear outcome. Ravens can show SADs also in a non-directional way, typically when they have temporarily left or are about to join the group. Acoustically, SADs can be highly variable between regions and individuals41 and a single individual may produce several distinct SAD types (personal observation). In our case, most birds within each group shared their vocal display repertoire regardless of their sex but varied in the frequency of certain SAD type usage (Supplementary Fig. 4). To create the stimuli, we used the two predominant SAD types from each group (Supplementary Table 3).

We constructed the dyadic interaction stimuli using vocalizations of six birds (three males and three females of consecutive ranks) from each group. Each stimulus approximated a dyadic interaction of a dominant (SAD vocalization) and subordinate (submissive vocalization) individual. We used the most frequent SAD type for each bird (Supplementary Table 3). Only within-sex interactions were considered. For each sex and group, this resulted in four stimuli of one rank step (two congruent and two incongruent with the actual group hierarchy) and two stimuli of two rank steps. In total, we obtained 24 playback stimuli (two groups × two sexes × three individuals × two congruency conditions).

Acoustic recordings of SADs and submissive calls were obtained between February 2011 and June 2012 from various non-experimental situations. All calls were recorded with a Sennheiser K6/ME66 shotgun microphone connected to a Marantz PMD660/Zoom H4n digital recorder or a Canon LEGRIA HD-camcorder. Best quality recordings were individually extracted, high-pass filtered at 200 Hz and peak amplitude normalized. SADs were normalized at −10 dB levels of the submissive calls to approximate the natural loudness difference between the two call types. Submissive calls are usually produced in bouts, which include adjacent calls without pause. For better approximation of the natural call occurrence, submissive calls were extracted singly or as two immediately adjacent calls.

Each individual stimulus consisted of a bout of three SADs from individual I immediately followed by a bout of five to seven submissive calls from individual II followed again by a single SAD from individual II (Fig. 6 and Supplementary Audio 1). SADs were spaced 2±0.2 s and submissive calls <0.5 s apart. The number of submissive calls varied between five and seven depending on the length of the individual calls in the stimulus. All individual calls were used no more than once within one stimulus and no more than three times within one playback session. We prepared stimuli using PRAAT 5.2.46 (ref. 42) and Adobe Audition CS5.5 software packages for mac OS X.

Figure 6: Example waveform of a playback stimulus.

Playback stimulus simulating an interaction between a dominant bird giving a bout of three SADs (individual I) followed by a bout of submissive vocalizations from a subordinate bird (individual II) and followed again by one SAD from the dominant.

Measures and data analyses

Before the experiments, we analysed the dominance hierarchies in both groups. Therefore, we provided the birds with a heap of food that could be monopolized by one individual and scored all unidirectional displacements38. We arranged these data in matrices with actors in rows and recipients in columns. We determined the dominance order most consistent with a linear hierarchy, calculating Landau’s linearity indices (h′) using MatMan 1.1 (ref. 43) and reordered matrices to best fit a linear hierarchy44, 45. We found significantly linear hierarchies in both groups (group 1: h′=0.964, n=8, P<0.001, based on 342 interactions and with 0% unknown relationships; group 2: h′=0.774, n=8, P=0.015, based on 403 interactions and 3.57% unknown relationships).

Videos of the experiments were coded with Solomon coder46 by J.S. who was blind for the congruence of the playback and for the sex of the played back individuals. Per playback, we coded 17 different behavioural variables (see Supplementary Table 4) during the 3.5 min of the playback (three playbacks a 10 s+2 min in between the three playbacks and 1 min post playback) and during the 3.5 min before the playback. Playbacks (12.5%) were recoded by Kerstin Pölzl. We used Spearman’s ρ-correlations to calculate inter-rater reliability regarding durational behaviours. All durational measures were scored almost identically, with Spearman’s ρ-correlation coefficients ranging between 0.73 and 1, and P≤0.001. Inter-rater reliability regarding point behaviours was calculated using Cohen’s κ. The value of κ was 0.68, which corresponds to a good level of agreement (91.2% agreement).

To reduce the amount of response variables, we performed a principle component analysis (PCA) on all behaviours coded during and before the playback. Note that if different sets of behaviours are found together before and after the playback, combining the two times might be hindering the PCA. Subtracting the behaviours found during the playback from the baseline before playback may lessen this problem. However, such a subtraction presumes an a priori difference between the phases, which would cause a problem for a subsequent PCA in case this difference is not present owing to a large amount of zeros in the data.

On the basis of eigenvalue (>1) and scree-plot investigation, we extracted five components that in total explained 53.4% of the overall variance of all data. On the basis of the variable loadings, the five components seem to reflect; 1, activity; 2, vocalization; 3, attention; 4, self-directed behaviour; and 5, ‘stress’ (Supplementary Table 4). Subsequently, we procured individual component scores for the five PCA components using the regression method. These component scores have a mean of zero and a variance equal to the squared multiple correlation between the estimated and the true component values.

To assess whether individuals reacted differently to playbacks with an expected interaction versus a playback with an unexpected interaction, we first calculated per component the difference between an individual’s component score during and before the playback that is, playback−baseline (delta).

Per component, we then used GLMM to assess the effect of condition (expected versus unexpected), sex of the subject, sex of the playback and age on the delta score. We ran separate analyses for the responses to in-group and to out-group stimuli. In these models, the delta of the component scores was the response variable, whereas condition, sex, sex of the playback and age were entered as fixed variables. Furthermore, as we dealt with repeated data, we structured our data as to represent the nested structure of our data. Particularly, we structured our data to be nested in each individual, which in turn were nested in one of the two groups. Consequently, we entered subject identity and group as random variables to our models. We ran models including all main effects and two-way interactions of sex and sex of the playback with condition, and several reduced models and selected the best fitting model with the Akaike Information Criteria. All reported P-values are two tailed, and we consider α≤0.05 as a significant effect. Where appropriate, we ran post hoc analyses using Wilcoxon-signed ranks tests.

References are available at the Nature site.

Spiritual Bypassing - from Teal Swan

 

"Spiritual Bypassing is the cancer of the spiritual world." Yes, yes it is. This is a nice, brief look at the topic from Teal (Tea Time with Teal) - The Spiritual Catalyst.

The best book on the subject, destined to become a classic text for spiritual seekers, is Robert Augustus Masters' Spiritual Bypassing: When Spirituality Disconnects Us from What Really Matters (2010).

Spiritual Bypassing

Published on Apr 26, 2014


Spiritual bypassing (or whitewashing) is the act of using spiritual beliefs to avoid facing or healing one's painful feelings, unresolved wounds and unmet needs. It is a state of avoidance. Because it is a state of avoidance, it is a state of resistance. I personally, consider Spiritual bypassing to be the shadow side of spirituality.

The spiritual beliefs of any spiritual tradition, be it Christian, Hindu, Buddhist, New Age, Islamic, or even Self Help, can provide ample justification for living in a state of inauthenticity. They can all provide justification for avoiding the unwanted aspects of one's own feelings and state of being in favor of what is considered to be "a more enlightened state". In this episode, Teal Swan gives examples of spiritual bypassing and suggests ways that we can avoid doing it.

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Ask Teal Website - http://www.askteal.com
Kuan Yin's Mantra (c) 2002 Lisa Thiel - used by permission http://www.sacreddream.com

All in the Mind - Too Much Reality (on PTSD)

A good episode of All in the Mind this week that looks at PTSD, particularly as related to war and combat. They also examine one of the newer treatment approaches, neurofeedback.

Too much reality

Lynne Malcolm  |  Sunday 27 April 2014

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• show transcript

Image: (Steve Jacobs (Getty))
It used to be known as shell shock but we now know that post traumatic stress disorder can develop in a range of contexts, and that the devastating symptoms are not only psychological and emotional, but can severely effect our physical health as well. Meet a retired SAS military commander and a Cambodian refugee who both know this only too well. We also hear about the latest treatments including neurofeedback.

Guests 

• Leahkhana Suos - Cambodian refugee & client at the NSW Service for the Treatment and Rehabilitation of Torture and Trauma Survivors (STARTS) 
• Stuart Bonner - Retired SAS military commander 
• Professor Sandy McFarlane
• Mirjana Askovic - Psychologist & Senior Neurofeedback Counsellor at the NSW Service for the Treatment and Rehabilitation of Torture and Trauma Survivors (STARTTS) 

Publications

Redback One: The True Story of an Australian SAS Hero by Robert Macklin

Further Information  

• NSW Service for the treatment and rehabilitation of torture and trauma survivors
• Veterans and veterans families counselling service
• Department of Veterans Affairs
• Lifeline 131114

Can Thomas Piketty's "Capital in the Twenty-First Century" Inspire Real Change?

It's rare for economist who is relatively unknown to have the #1 book at Amazon, but Thomas Piketty, author of Capital in the Twenty-First Century, has done so.

Everywhere I look lately there is someone offering commentary on and support of this "revolutionary" book. Here is a selection of recent articles/videos about the book, including a talk by the author.

Here are the questions he's trying to answer in Capital:

The distribution of wealth is one of today’s most widely discussed and controversial issues. But what do we really know about its evolution over the long term? Do the dynamics of private capital accumulation inevitably lead to the concentration of wealth in ever fewer hands, as Karl Marx believed in the nineteenth century? Or do the balancing forces of growth, competition, and technological progress lead in later stages of development to reduced inequality and greater harmony among the classes, as Simon Kuznets thought in the twentieth century? What do we really know about how wealth and income have evolved since the eighteenth century, and what lessons can we derive from that knowledge for the century now under way?

To begin, here is Piketty himself talking about the thesis of his book, followed by Elizabeth Warren offering her well-educated perspective, then a LOT of article teasers to offer a variety of perspectives.

Thomas Piketty on Wealth, Income, and Inequality

Elizabeth Warren Weighs In On The Thomas Piketty Phenomenon

Elizabeth Warren Weighs In On The Thomas Piketty Phenomenon

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Will Hutton from The Guardian:

Capitalism simply isn't working and here are the reasons why

Economist Thomas Piketty's message is bleak: the gap between rich and poor threatens to destroy us

• Thomas Piketty interview: capitalism just doesn't add up

Suddenly, there is a new economist making waves – and he is not on the right. At the conference of the Institute of New Economic Thinking in Toronto last week, Thomas Piketty's book Capital in the Twenty-First Century got at least one mention at every session I attended. You have to go back to the 1970s and Milton Friedman for a single economist to have had such an impact.

Like Friedman, Piketty is a man for the times. For 1970s anxieties about inflation substitute today's concerns about the emergence of the plutocratic rich and their impact on economy and society. Piketty is in no doubt, as he indicates in an interview in today's Observer New Review, that the current level of rising wealth inequality, set to grow still further, now imperils the very future of capitalism. He has proved it.

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Heidi Moore at Common Dreams (via The Guardian):

Can Thomas Piketty Re-Write the American Dream?

by Heidi Moore
Published on Sunday, April 27, 2014 by The Guardian
 
Piketty's immaculate research establishes that the American dream – and more broadly, the egalitarian promise of Western-style capitalism – does not, and maybe cannot, deliver on its promises. Photo: Ed Alcock for the Observer

When the movie is made about the fall of Western capitalism, Thomas Piketty will be played by Colin Firth. Piketty, whom the Financial Times called a "rock-star economist", isn't a household name – but he should be, and he has a better shot than any other economist. He is the author and researcher behind a 700-page economic manifesto, titled Capital in the 21st Century, that details the path of income inequality over several hundred years.

This sublime nerdishness is, somehow, a huge hit. It is now No 1 on Amazon's bestseller list and sold out in many bookstores. When Piketty spoke on a panel this month at New York's CUNY with three other economists – two of them Nobel-prize winners, Joseph Stiglitz and Paul Krugman – the Frenchman was the headliner. The event was so packed that the organizers had to create three overflow rooms. Weeks after the release of Capital, intellectuals are still salivating, even calling Piketty the new de Tocqueville.

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Justin Fox at the Harvard Business Review:

Piketty’s “Capital,” in a Lot Less than 696 Pages

by Justin Fox | April 24, 2014

It was only published in English a few weeks ago, but French economist Thomas Piketty’s Capital in the Twenty-First Century has already become inescapable. The reasons start with the confluence of subject matter and author. There’s a lot of interest in economic inequality these days, and research conducted over the past 15 years by Piketty, a professor at the Paris School of Economics, is a big reason why. In the U.S., Piketty and UC Berkeley’s Emmanuel Saez transformed a tame discussion of income quintiles and deciles into a sharp debate about the skyrocketing incomes of the 1% — and the mind-boggling gains of the 0.1% and 0.01% — by gathering and publishing income tax data that nobody had bothered with before. Piketty was behind similar projects in France, Britain, Japan, and other countries.

And now this book. It is massive (696 pages) and massively ambitious (the title is a very conscious echo of Karl Marx’s Das Kapital). It came out in France last year to great acclaim, which meant that those in the English-speaking world who pay attention to such matters knew that something big was coming. Over the past few weeks it has become one of those things that everybody’s talking about just because everybody’s talking about it. That, and it really is important.

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Sean McElwee at Salon:

Welcome to the Piketty revolution: “Capital in the 21st Century” is a game-changer (even if you never read it)

"Capital in the 21st Century" is an unexpected bestseller that could actually change the world 
Sean McElwee | Sunday, Apr 27, 2014 

 

Thomas Piketty (Credit: Reuters/Charles Platiau/Salon)

 

Anyone who’s anyone (and many more who aren’t) has written something this week about “Capital in the 21st Century,” the new treatise on income inequality by French economist Thomas Piketty.

The book was actually published early last month by Harvard University Press, but arrived to fanfare only within the insular, if august, community of economic policy researchers. So, on arrival, it might have seemed like the 700-page tome, with its academic tone and laboriously documented historical analyses, was destined to a life of obscurity. But then something strange happened. People — regular people — started to buy it in droves. By the time “Capital” surged to the top of the charts this week — so many physical copies of the book were sold that Amazon actually ran out of inventory — Thomas Piketty had become the most famous economist this side of Paul Krugman, celebrated on the left and reviled on the right.

At this point, a review or discussion of “Capital” is almost a rite of passage for an aspiring wonk. (You can read this writer’s here.) But the one question that hangs over Piketty’s meteoric rise is, in a way, the most obvious one: What does any of this actually mean?

 * * * * *

From Ryan Decker at Updated Priors:

Capital in partial equilibrium

Ryan Decker | Tuesday, March 25, 2014
Review: Thomas Piketty, Capital in the Twenty-First Century

Piketty's primary contribution is to provide an impressive array of data on wealth and income, for several countries, beginning as early as the 1700s in some cases. Note that he does not examine consumption data. The book is an impressive feat and certainly deserves attention, as the facts Piketty provides are crucial to discussions of the evolution of capital and economic inequality in the rich countries. Many reviews have been very positive; there are a lot of positive things I could say about it, but I will leave that to others. The book suffers from some fundamental flaws; in short, while it is heavy on data it is light on serious economics. Readers will find themselves wading through hundreds of pages of opinion and ideological quips, not economic analysis, with interesting charts scattered throughout. The firehose of data can be overwhelming, which may explain why some reviewers internalized his arguments uncritically. Piketty's accomplishments with data collection are admirable. But a book of this size, with the title Capital, should include some economics.

Piketty's data on inheritance are the most interesting and persuasive to me. Inheritance still matters and plays a nontrivial role in the wealth and income distribution. Reducing wealth inequality over time, should we decide to do so, will require serious attention to the issue of inheritance, which more than any other issue lacks a tie to meritocracy (but that does not mean incentives stop mattering!). There may be other arguments, not based solely on inequality, for thinking about inheritance. That said, not all capital is created equal, and the book could have benefited from some focus on distinctions between capital types--particularly in the context of inheritance.