low noise

Unexpected arousal shapes confidence – blog and news coverage

For those looking for a good summary of our recent publication, several outlets gave us solid coverage for expert and non-expert alike. Here is a short summary of the most useful write-ups:

The eLife digest itself was excellent – make sure to fill out the survey at the end to let eLife know what you think of the digests  (I love them).

via Arousing confidence – Brains and Behaviour – Medium

As you read the words on this page, you might also notice a growing feeling of confidence that you understand their meaning. Every day we make decisions based on ambiguous information and in response to factors over which we have little or no control. Yet rather than being constantly paralysed by doubt, we generally feel reasonably confident about our choices. So where does this feeling of confidence come from?

Computational models of human decision-making assume that our confidence depends on the quality of the information available to us: the less ambiguous this information, the more confident we should feel. According to this idea, the information on which we base our decisions is also the information that determines how confident we are that those decisions are correct. However, recent experiments suggest that this is not the whole story. Instead, our internal states — specifically how our heart is beating and how alert we are — may influence our confidence in our decisions without affecting the decisions themselves.

To test this possibility, Micah Allen and co-workers asked volunteers to decide whether dots on a screen were moving to the left or to the right, and to indicate how confident they were in their choice. As the task became objectively more difficult, the volunteers became less confident about their decisions. However, increasing the volunteers’ alertness or “arousal” levels immediately before a trial countered this effect, showing that task difficulty is not the only factor that determines confidence. Measures of arousal — specifically heart rate and pupil dilation — were also related to how confident the volunteers felt on each trial. These results suggest that unconscious processes might exert a subtle influence on our conscious, reflective decisions, independently of the accuracy of the decisions themselves.

The next step will be to develop more refined mathematical models of perception and decision-making to quantify the exact impact of arousal and other bodily sensations on confidence. The results may also be relevant to understanding clinical disorders, such as anxiety and depression, where changes in arousal might lock sufferers into an unrealistically certain or uncertain world.

The PNAS journal club also published a useful summary, including some great quotes from Phil Corlett and Rebecca Todd:

via Journal Club: How your body feels influences your confidence levels | National Academy of Sciences

… Allen’s findings are “relevant to anyone whose job is to make difficult perceptual judgments trying to see signal in a lot of noise,” such as radiologists or baggage inspectors, says cognitive neuroscientist Rebecca Todd at the University of British Columbia in Vancouver, who did not take part in the research. Todd suggests that people who apply decision-making models to real world problems need to better account for the influence of internal or emotional states on confidence.

The fact that bodily states can influence confidence may even shed light on mental disorders, which often involve blunted or heightened signals from the body. Symptoms could result from how changes in sensory input affect perceptual decision-making, says cognitive neuroscientist and schizophrenia researcher Phil Corlett at Yale University, who did not participate in this study.

Corlett notes that some of the same ion channels involved in regulating heart rate are implicated in schizophrenia as well. “Maybe boosting heart rate might lead people with schizophrenia to see or hear things that aren’t present,” he speculates, adding that future work could analyze how people with mental disorders perform on these tasks…

I also wrote a blog post summarizing the article for The Conversation:

via How subtle changes in our bodies affect conscious awareness and decision confidence

How do we become aware of our own thoughts and feelings? And what enables us to know when we’ve made a good or bad decision? Every day we are confronted with ambiguous situations. If we want to learn from our mistakes, it is important that we sometimes reflect on our decisions. Did I make the right choice when I leveraged my house mortgage against the market? Was that stop light green or red? Did I really hear a footstep in the attic, or was it just the wind?

When events are more uncertain, for example if our windscreen fogs up while driving, we are typically less confident in what we’ve seen or decided. This ability to consciously examine our own experiences, sometimes called introspection, is thought to depend on the brain appraising how reliable or “noisy” the information driving those experiences is. Some scientists and philosophers believe that this capacity for introspection is a necessary feature of consciousness itself, forging the crucial link between sensation and awareness.

One important theory is that the brain acts as a kind of statistician, weighting options by their reliability, to produce a feeling of confidence more or less in line with what we’ve actually seen, felt or done. And although this theory does a reasonably good job of explaining our confidence in a variety of settings, it neglects an important fact about our brains – they are situated within our bodies. Even now, as you read the words on this page, you might have some passing awareness of how your socks sit on your feet, how fast your heart is beating or if the room is the right temperature.

Even if you were not fully aware of these things, the body is always shaping how we experience ourselves and the world around us. That is to say experience is always from somewhere, embodied within a particular perspective. Indeed, recent research suggests that our conscious awareness of the world is very much dependent on exactly these kinds of internal bodily states. But what about confidence? Is it possible that when I reflect on what I’ve just seen or felt, my body is acting behind the scenes? …

The New Scientist took an interesting angle not as explored in the other write-ups, and also included a good response from Ariel Zylberberg:

via A bit of disgust can change how confident you feel | New Scientist

“We were tricking the brain and changing the body in a way that had nothing to do with the task,” Allen says. In doing so, they showed that a person’s sense of confidence relies on internal as well as external signals – and the balance can be shifted by increasing your alertness.

Allen thinks the reaction to disgust suppressed the “noise” created by the more varied movement of the dots during the more difficult versions of the task. “They’re taking their own confidence as a cue and ignoring the stimulus in the world.”

“It’s surprising that they show that confidence can be motivated by processes inside a person, instead of what we tend to believe, which is that confidence should be motivated by external things that affect a decision,” says Ariel Zylberberg at Columbia University in New York. “Disgust leads to aversion. If you try a food and it’s disgusting, you walk away from it,” says Zylberberg. “Here, if you induce disgust, high confidence becomes lower and low confidence becomes higher. It could be that disgust is generating this repulsion.”

It is not clear whether it is the feeling of disgust that changes a person’s confidence in this way, or whether inducing alertness with a different emotion, such as anger or fear, would have the same effect.

You can find all the coverage for our article using these excellent services, altmetric & ImpactStory.

https://www.altmetric.com/details/12986857

https://impactstory.org/u/0000-0001-9399-4179/p/mfatd6ZhpW

Thanks to everyone who shared, enjoyed, and interacted with our research!

 

The 2011 Mind & Life Summer Research Institute: Are Monks Better at Introspection?

As I’m sitting in the JFK airport waiting for my flight to Iceland, I can’t help but let my mind wander over the curious events of this year’s summer research institute (SRI). The Mind & Life Institute, an organization dedicated to the integration and development of what they’ve dubbed “contemplative science”, holds the SRI each summer to bring together clinicians, neuroscientists, scholars, and contemplatives (mostly monks) in a format that is half conference and half meditation retreat. The summer research institute is always a ton of fun, and a great place to further one’s understanding of Buddhism & meditation while sharing valuable research insights.

I was lucky enough to receive a Varela award for my work in meta-cognition and mental training and so this was my second year attending. I chose to take a slightly different approach from my first visit, when I basically followed the program and did whatever the M&L thought was the best use of my time. This meant lots of meditation- more than two hours per day not including the whole-day, silent “mini-retreat”. While I still practiced this year, I felt less obliged to do the full program, and I’m glad I took this route as it provided me a somewhat more detached, almost outsider view of the spectacle that is the Mind & Life SRI.

When I say spectacle, it’s important to understand how unconventional of a conference setting the SRI really is. Each year dozens of ambitious neuroscientists and clinicians meet with dozens of Buddhist monks and western “mindfulness” instructors. The initial feeling is one of severe culture clash; ambitious young scholars who can hardly wait to mention their Ivy League affiliations meet with the austere and almost ascetic approach of traditional Buddhist philosophy. In some cases it almost feels like a race to “out-mindful” one another, as folks put on a great show of piety in order to fit into the mood of the event. It can be a bit jarring to oscillate between the supposed tranquility and selflessness of mindfulness with the unabashed ambition of these highly talented and motivated folk- at least until things settle down a bit.

Nonetheless, the overall atmosphere of the SRI is one of serenity and scholarship. It’s an extremely fun, stimulating event, rich with amazingly talented yoga and meditation instructors and attended by the top researchers within the field. What follows is thus not meant as any kind of attack on the overall mission of the M&L. Indeed, I’m more than grateful to the institute for carrying on at least some form of Francisco Varela’s vision for cognitive science, and of course for supporting my own meditation research. With that being said, we turn to the question at hand: are monks objectively better at introspection? The answer for nearly everyone at the SRI appear to be “yes”, regardless of the scarcity of data suggesting this to be the case.

Enactivism and Francisco Varela

Francisco Varela, founder of EnactivismBefore I can really get into this issue, I need to briefly review what exactly “enactivism” is and how it relates to the SRI. The Mind & Life institute was co-founded by Francisco Varela, a Chilean biologist and neuroscientist who is often credited with the birth and success of embodied and enactive cognitive science. Varela had a profound impact on scientists, philosophers, and cognitive scientists and is a central influence in my own theoretical work. Varela’s essential thesis was outlined in his book “The Embodied Mind”, in which Varela, Thompson, and Rosch, attempted to outline a new paradigm for the study of mind. In the book, Varela et al rely on examples from cross-cultural psychology, continental phenomenology, Buddhism, and cognitive science to argue that cognition (and mind) is essentially an embodied, enactive phenomenon. The book has since spawned a generation of researchers dedicated in some way to the idea that cognition is not essentially, or at least foundationally, computational and representational in form.

I don’t here intend to get into the roots of what enactivism is; for the present it suffices to say that enactivism as envisioned by Varela involved a dedication to the “middle way” in which idealism-objectivism duality is collapsed in favor of a dynamical non-representational account of cognition and the world. I very much favor this view and try to use it productively in my own research. Varela argued throughout his life that cognition was not essentially an internal, info-processing kind of phenomenon, but rather an emergent and intricately interwoven entity that arose from our history of structural coupling with the world.  He further argued that cognitive science needed to develop a first-person methodology if it was to fully explain the rich panorama of human consciousness.

A simpler way to put this is to say that Varela argued persuasively that minds are not computers “parachuted into an objective world” and that cognition is not about sucking up impoverished information for representation in a subjective format. While Varela invoked much of Buddhist ontology, including concepts of “emptiness” and “inter-relatedness”, to develop his account continental phenomenologists like Heidegger and Merleau-Ponty also heavily inspired his vision of 4th wave cognitive science.  At the SRI there is little mention of this; most scholars are unaware of the continental literature or that phenomenology is not equal to introspection. Indeed I had to cringe when one to-be-unnamed young scientist declared a particular spinal pathway to be “the central pathway for embodiment”.

This is a stark misunderstanding of just what embodiment means, and I would argue renders it a relatively trivial add-on to the information processing paradigm- something most enactivists would like to strongly resist. I politely pointed the gentleman to the example work of Ulric Neisser, who argued for the ecological embodied self, in which the structure of the face is said to pre-structure human experience in particular ways, i.e. we typically experience ourselves as moving through the world toward a central fovea-centered point. Embodiment is an external, or pre-noetic structuring of the mind; it follows no nervous pathway but rather structures the possibilities of the nervous system and mind. I hope he follows that reference down the rabbit hole of the full possibilities of embodiment- the least of which is body-as-extra-module.

Still, I certainly couldn’t blame this particular scientist for his mis-understanding; nearly everyone at the SRI is totally unfamiliar with externalist/phenomenal perspectives, which is a sad state of affairs for a generation of scientists being supported by grants in Varela’s name. Regardless of Varela’s vision for cognitive science, his thesis regarding introspectionism is certainly running strong: first-person methodologies are the hot topic of the SRI, and nearly everyone agreed that by studying contemplative practitioners’ subjective reports, we’d gain some special insight into the mind.  Bracketing whether introspection is what Varela really meant by neurophenomenology (I don’t think it is- phenomenology is not introspection) we are brought to the central question: are Buddhist practitioners expert introspectionists?

Expertise and Introspectionism

Expert introspectionists?Varela certainly believed this to some degree. It’s not entirely clear to me that the bulk of Varela’s work summates to this maxim, but it’s at least certainly true that in papers such as his seminal “Neurophenomenology: a methodological remedy to the hard problem?” he argued that a careful first-person methodology could reap great benefits in this arena. Varela later followed up this theoretical thesis with his now well-known experiment conducted with then PhD student and my current mentor Antoine Lutz.

While I won’t reproduce the details of this experiment at length here, Lutz and Varela demonstrated that it was in fact possible to inform and constrain electrophysiological measurements through the collection and systemization of first-person reports. It’s worth noting here that the participants in this experiment were every day folks, not meditation practitioners, and that Lutz & Varela developed a special method to integrate the reports rather than taking them simply at face value. In fact, while Varela did often suggest that we might through careful contemplation and collaboration with the Buddhist tradition refine first person methodologies and gain insight into the “hard-problem”, he never did complete these experiments with practitioners, a fact that can likely be attributed to his pre-mature death at the hand of aggressive hepatitis.

Regardless of Varela’s own work, it’s fascinating to me that at today’s SRI, if there is one thing nearly everyone seems to explicitly agree on, it’s that meditation practitioners have some kind of privileged access to experience. I can’t count how many discussions seemed to simply assume the truth of this, regardless of the fact that almost no empirical research has demonstrated any kind of increased meta-cognitive capacity or accuracy in adept contemplatives.

While Antoine and I are in fact running experiments dedicated to answering this question, the fact remains that this research is largely exploratory and without strong empirical leads to work from. While I do believe that some level of meditation practice can provide greater reliability and accuracy in meta-cognitive reports, I don’t see any reason to value the reports of contemplative practitioners above and beyond those of any other particular niche group. If I want to know what it’s like to experience baseball, I’m probably going to ask some professional baseball players and not a Buddhist monk. At several points during the SRI I tried to express just this sentiment; that studying Buddhist monks gives us a greater insight into what-it-is-like to be a monk and not much else. I’m not sure if I succeeded, but I’d like to think I planted a few seeds of doubt.

There are several reasons for this. First, I part with Varela where he assumes that the Buddhist tradition and/or “Buddhist Psychology” have particularly valuable insights (for example, emptiness) that can’t be gleaned from western approaches. It might, but I don’t buy into the idea that the Buddhist tradition is its own kind of scientific approach to the mind; it’s not- it’s religion. For me the middle way means a lifelong commitment to a kind of meta-physical agnosticism, and I refuse to believe that any human tradition has a vast advantage over another. This was never more apparent than during a particularly controversial talk by John Dunne, a Harvard contemplative scholar, whose keynote was dedicated to getting scientists like myself to go beyond the traditional texts and veridical reports of practitioners and to instead engage in what he called “trialogue” in order to discover “what it is practitioners are really doing”. At the end of his talk one of the Dalai Lama’s lead monks actually took great offense, scolding John for “misleading the youth with his western academic approach”. The entire debacle was a perfect case-in-point demonstration of John’s talk; one cannot simply take the word of highly religious practitioners as some kind of veridical statement about the world.

This isn’t to say that we can’t learn a great deal about experience, and the mind, through meditation and careful introspection. I think at an early level it’s enough to just sit with ones breath and suspend beliefs about what exactly experience is. I do believe that in our modern lives; we spend precious little time with the body and our minds, simply observing what arises in a non-partial way.  I agree with Sogyal Rinpoche that we are at times overly dis-embodied and away from ourselves. Yet this practice isn’t unique to Buddhism; the phenomenological reduction comes from Husserl and is a practice developed throughout continental phenomenology. I do think that Buddhism has developed some particularly interesting techniques to aid this process, such as Vipassana and compassion-meditation, that can and will shed insights for the cognitive scientist interested in experience, and I hope that my own work will demonstrate as much.

But this is a very different claim from the one that says monastic Buddhists have a particularly special access to experience. At the end of the day I’m going to hedge my bets with the critical, empirical, and dialectical approach of cognitive science. In fact, I think there may be good reasons to suspect that high-level practitioners are inappropriate participants for “neurophenomenology”. Take for example, the excellent and controversial talk given this year by Willoughby Britton, in which she described how contemplative science had been too quick to sweep under the rug a vast array of negative “side-effects” of advanced practice. These effects included hallucination, de-personalization, pain, and extreme terror. This makes a good deal of sense; advanced meditation practice is less impartial phenomenology and more a rigorous ritualized mental practice embedded in a strong religious context. I believe that across cultures many religions share techniques, often utilizing rhythmic breathing, body postures, and intense belief priming to engender an almost psychedelic state in the practitioner.

What does this mean for cognitive science and enactivism? First, it means we need to respect cultural boundaries and not rush to put one cultural practice on top of the explanatory totem pole. This doesn’t mean cognitive scientists shouldn’t be paying attention to experience, or even practicing and studying meditation, but we have to be careful not to ignore the normativity inherent in any ritualized culture. Embracing this basic realization takes seriously individual and cultural differences in consciousness, something I’ve argued for and believe is essential for the future of 4th wave cognitive science. Neurophenomenology, among other things, should be about recognizing and describing the normativity in our own practices, not importing those of another culture wholesale. I think that this is in line with much of what Varela wrote, and luckily, the tools to do just this are richly provided by the continental phenomenological tradition.

I believe that by carefully bracketing meta-physical and normative concepts, and investigating the vast multitude of phenomenal experience in its full multi-cultural variety, we can begin to shed light on the mind-brain relationship in a meaningful and not strictly reductive fashion. Indeed, in answering the question “are monks expert introspectionists” I think we should carefully question the normative thesis underlying that hypothesis- what exactly constitutes “good” experiential reports? Perhaps by taking a long view on Buddhism and cognitive science, we can begin to truly take the middle way to experience, where we view all experiential reports as equally valid statements regarding some kind of subjective state. The question then becomes primarily longitudinal, i.e. do experiential reports demonstrate a kind of stability or consistency over time, how do trends in experiential reports relate to neural traits and states, and how do these phenomena interact with the particular cultural practices within which they are embedded. For me, this is the central contribution of enactive cognitive science and the best way forward for neurophenomenology.

Disclaimer: I am in no way suggesting enactivists cannot or should not study advanced buddhism if that is what they find interesting and useful. I of course realize that the M&L SRI is a very particular kind of meeting, and that many enactive cognitive scientists can and do work along the lines I am suggesting. My claim is regarding best practices for the core of 4th wave cognitive science, not the fringe. I greatly value the work done by the M&L and found the SRI to be an amazingly fruitful experience.

Brain Plasticity, Distributed Social Cognition, and the Luddite Notion.

With the integration of Facebook, Twitter, Wikipedia, and Google, the web has stepped closer still to being a social media technology. These tools have spread throughout the structure of the net and are currently enjoying widespread adoption by all sectors of developed society. As the elderly invade Facebook (with embarrassing consequences) and youth abandon traditional forms of media, many are wondering what some of the consequences might be. Will twitter make us stupid? I think the following excerpt has some great insights:

The above is a snippet from Merlin Donald’s excellent book, The Origins of The Modern Mind, taken from Andy Clark’s also sublime Natural Born Cyborgs. There are several very interesting aspects of this text that I think are relevant for my research and this blog. The first is the striking resemblance of Donald’s imagined drama to that which is currently unfolding concerning the emergence of social media technologies (SMTs). See for example, the Baroness Greenfield’s recent diatribe against all things Twitter and Facebook:

‚Äú[Social networking sites] are devoid of cohesive narrative and long-term significance. As a consequence, the mid-21st century mind might almost be infantilised, characterised by short attention spans, sensationalism, inability to empathise and a shaky sense of identity”- Baroness Greenfield

These kinds of claims have been echoed across the popular press and blogosphere. They amount to an exact approximation of the ‚Äúfear that [language] was sure to encourage great laziness and to stop people from thinking for themselves‚Äù. The similarity continues- ‚Äúif you could ask someone for the answer, who would bother to learn anything.‚Äù These fears clearly trade on the same metaphors. They are couched in a basic recognition that like language, the social media is profoundly altering the way we create, store, and share knowledge. In fact, part of what makes social media so interesting is the precise way in which it enables and enhances our language abilities. Social media lets millions of users contribute small bits of linguistic intelligence to an otherwise ‘dumb’ repository of information. The collective tagging, sharing, ranking, blogging, and evaluating of the web results in a collective knowledge base that reshapes our possibilities for action. This is not unlike the role of language in Merlin’s example, or in Andy Clark’s famous examples of how wrist watches or notepads reshape our ability to plan actiond and coordinate with one another.

“The process of which Donald speaks is the public, collective version of the kind of scaffolded thinking and reasoning described earlier. Just as I might use pen and paper to freeze my own half-baked thoughts, turning them into stable objects for further thought and reflection, so we (as a society) learned to use the written word to power a process of collective thinking and critical reason. The tools of text… thus allow us at multiple scales, to create new stable objects for critical activity… With speech, text, and the tradition of using them as critical tools under our belts, humankind entered the first phase of its cyborg existence (Andy Clark in Natural Born Cyborgs).

So should we be worried? I think it depends largely on your ethical and political stance on technology. Some, perhaps those most inspired by a Kazinski-esque desire to return to some basic primitive lifestyle, seem to embrace a basic notion that technology is the root of all evil. My own stance is that such a view is brazenly ignorant of reality. We cannot go back- the mind of modern man has been revolutionized not only by the emergence of language and analytic thinking, but by the products- the artifacts and tools that have come about as a direct consequence of the radical transformation in our mental fabric, brought about by symbolic language. I would like to suggest that the emergence of the internet, and its’ refinement via social technology, represents a new stage of cognitive development- using Merlin’s terms, a revolutionary synthesis of mythic, narrative, and analytic thinking- but that is the subject for another post.

Back to the topic at hand. Simply put, everything changes our brains. Research now suggests that across the human brain, both synapses and somas are profoundly capable of adaptation to new experiences [1]. Andy Clark argues that human brains have evolved such remarkable plasticity to make use of new tools in ways that other animals cannot, via the actual integration of tools into our distributed cognitive system. An accurate metaphor is found in embodiment- we typically do not pay reflective attention to our bodies. Rather, we use them as fluid extensions of our intentions. Tool use is also like this- the hammer in the hand of a skilled carpenter becomes transparent. Recent neuroscience backs this up, as Andy points out, with studies demonstrating that the visual receptive fields of monkeys will instantly extend to include the length of a stick when it is used by the animal. The tool-world-mind relationship is thus dynamic- the brain/mind integrates tools into its’ very fabric. We are natural born cyborgs, distributed cognitive systems of flesh and tool. Thus, the introduction of agriculture brought about alterations in diet that no doubt influenced our metabolism and facilitated new and divergent brain growth. Social media alarmism is just another iteration of technological conservatism, and in its’ current form really only blinds us to the real benefits and pitfalls of these technologies.

What about the brain? Pre-frontal connectivity (prevalence of white matter) is perhaps a singular anatomical marker of brain difference between human and chimpanzee [2]. Further studies in neurobiology indicate that the degree of plasticity may be greater within axonal white matter than any other neural component [3].

If you follow Clark‚Äôs line of argument, then the brain is essentially a plasticity mechanism, forming the flexible center-piece in a brain-tool-world distributed loop. The profound neuroplasticity found in the human brain is thus both product and enabler of technocultural advances. We should no more fear the introduction of social media than we can go back and undo the development of language, or the innovation of common garden tools. Rather, we should begin to examine these new tools, and the other products of the digital era- video games, blogs, social networks, crowdsourcing, and googling, as the next revolution in cognitive innovation. By appreciating the full scope of SMTs, I believe we can open a new era of neurocognitive research. Does Facebook give us ADHD? Probably not- but you can be sure its doing something to our basic cognitive abilities. Look for many more posts on this topic from Neuroconscience, and eventually… some actual data on this highly speculative debate! You read it here first😉

References:

[1] Green CS, Bavelier D. (2008): Exercising your brain: a review of human brain plasticity and training-induced learning. Psychology and aging 23(4):692-701.

[2] Schoenemann PT, Sheehan MJ, Glotzer LD. (2005): Prefrontal white matter volume is disproportionately larger in humans than in other primates. Nat Neurosci 8(2):242-52.

[3] Stettler DD, Yamahachi H, Li W, Denk W, Gilbert CD. (2006): Axons and synaptic boutons are highly dynamic in adult visual cortex. Neuron 49(6):877-87.

The Collaborative Mind

Neuroplasticity and Cybernetic Social Cognition

Here is the abstract for my upcoming talk at the Poznan Cognition Forum, entitled “The Collaborative Mind: Neuroplasticity and Cybernetic Social Cognition”.

“With the advent of multi-level findings demonstrating neuroplasticity in the adult brain, neuroscience is currently undergoing a decisive paradigm change. Although Ram√≥n y Cajal, the father of the neuron doctrine, first speculated that synaptic neuroplasticity might be the fundamental mechanism of learning, neurogenesis has remained a controversial hypothesis. Recent multi-method research has overturned this dogma, finding dramatic plasticity at cellular, cognitive, developmental, and axonal levels. I review these findings, arguing that neuroplasticity challenges traditional understandings of the mind and cognition while presenting an upcoming fMRI project investigating social-media, cognitive augmentation, and neuroplasticity.”

Stay tuned for links to my presentation, and pictures of Poznan!

Some choice graphics from the talk: