Posts Tagged ‘perception’
“I love to talk about nothing. It’s the only thing I know anything about.”*…
It took centuries for people to embrace the zero. Now, as Benjy Barnett explains, it’s helping neuroscientists understand how the brain perceives absences…
When I’m birdwatching, I have a particular experience all too frequently. Fellow birders will point to the tree canopy and ask if I can see a bird hidden among the leaves. I scan the treetops with binoculars but, to everyone’s annoyance, I see only the absence of a bird.
Our mental worlds are lively with such experiences of absence, yet it’s a mystery how the mind performs the trick of seeing nothing. How can the brain perceive something when there is no something to perceive?
For a neuroscientist interested in consciousness, this is an alluring question. Studying the neural basis of ‘nothing’ does, however, pose obvious challenges. Fortunately, there are other – more tangible – kinds of absences that help us get a handle on the hazy issue of nothingness in the brain. That’s why I spent much of my PhD studying how we perceive the number zero.
Zero has played an intriguing role in the development of our societies. Throughout human history, it has floundered in civilisations fearful of nothingness, and flourished in those that embraced it. But that’s not the only reason it’s so beguiling. In striking similarity to the perception of absence, zero’s representation as a number in the brain also remains unclear. If my brain has specialised mechanisms that have evolved to count the owls perched on a branch, how does this system abstract away from what’s visible, and signal that there are no owls to count?
The mystery shared between the perception of absences and the conception of zero may not be coincidental. When your brain recognises zero, it may be recruiting fundamental sensory mechanisms that govern when you can – and cannot – see something. If this is the case, theories of consciousness that emphasise the experience of absence may find a new use for zero, as a tool with which to explore the nature of consciousness itself…
[Barnett provides a fascinating history of the zero, of its uses, and of brain scientost’s attepts to understand the (not so masterful) human ability to perceive absence…]
… All of this returns us to zero. The question is, does the same underlying neural mechanism drive experiences of both zero and perceptual absence? If it does, this would show us that, when we’re engaged in mathematics using zero, we’re also invoking a more fundamental and automatic cognitive system – one that is, for instance, responsible for detecting an absence of birds when I’m birdwatching.
The brain systems used to extract positive numbers from the environment are relatively well understood. Parts of the parietal cortex have evolved to represent the number of ‘things’ in our environment while stripping away information of what those ‘things’ are. This system would simply indicate ‘four’ if I saw four owls, for example. It is thought to be central to learning the structure of our environment. If the neural systems that govern our ability to decide if we consciously see something or not were found to rely on this same mechanism, it would help theories like HOSS and PRM get a handle on how exactly this ability arises. Perhaps, just as this system learns the structure and regularities of our environment, it also learns the structure of our brain’s sensory activity to help determine when we have seen something. This is what PRM and HOSS already predict, but grounding the theories in established ideas about how the brain works may provide them with a stronger foothold in explaining the precise mechanisms that allow us to become aware of the world.
An intriguing hypothesis inspired by the ideas above is that, if the brain basis of zero relies on the kinds of absence-related neural mechanisms that the above frameworks take to be necessary for conscious experience, then for any organism to successfully employ the concept of zero, it might first need to be perceptually conscious. This would mean that understanding zero could act as a marker for consciousness. Given that even honeybees have been shown to enjoy a rudimentary concept of zero, this may seem – at least to some – far fetched. Nonetheless, it seems attractive to suggest that the similarities between numerical and perceptual absences could help reveal the neural basis of not only experiences of absence but conscious awareness more broadly. Jean-Paul Sartre testified that nothingness was at the heart of being, after all.
The evolution of the number zero helped unlock the secrets of the cosmos. It remains to be seen whether it can help to unpick the mysteries of the mind. For now, studying it has at least led to less disappointment about my birdwatching failures. Now I know that there’s great complexity in seeing nothing and that, more importantly, nothing really matters…
Noodling on nowt: “Why nothing matters,” from @benjyb.bsky.social in @aeon.co.
Apposite: Percival Everett‘s glorious novel, Dr. No.
* Oscar Wilde
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As we analyze our apprehension of absence, we might send empty bithday greetings to a man who ruled out the use of “0” in one specific case: Georg Ohm; he was born on this date in 1789. A mathematician and physicist, he demonstrated by experiment (in 1825) that there are no “perfect” electrical conductors– that’s to say, no conductors with 0 resistance.
Working with the new electrochemical cell, invented by Italian scientist Alessandro Volta, Ohm found that there is a direct proportionality between the potential difference (voltage) applied across a conductor and the resultant electric current— a relationship since known as Ohm’s law (V=iR). The SI unit of resistance is the ohm (symbol Ω).
“The world of reality has its limits; the world of imagination is boundless”*…
Still, it’s useful to know the difference… and as Yasemin Saplakoglu explains, that’s a complex process– one that science takes very seriously…
As I sit at my desk typing up this newsletter, I can see a plant to my left, a water bottle to my right and a gorilla sitting across from me. The plant and bottle are real, but the gorilla is a product of my mind — and I intuitively know that this is true. That’s because my brain, like most people’s, has the ability to distinguish reality from imagination. If it didn’t, or if I had a condition that disrupts this distinction, I’d constantly see gorillas and elephants where they don’t exist.
Imagination is sometimes described as perception in reverse. When we look at an object, electromagnetic waves enter the eyes, where they are translated into neural signals that are then sent to the visual cortex at the back of the brain. This process generates an image: “plant.” With imagination, we start with what we want to see, and the brain’s memory and semantic centers send signals to the same brain region: “gorilla.”
In both cases, the visual cortex is activated. Recalling memories can also activate some of the same regions. Yet the brain can clearly distinguish between imagination, perception and memory in most cases (though it is still possible to get confused). How does it keep everything straight?
By probing the differences between these processes, neuroscientists are untangling how the human brain creates our experience. They’re finding that even our perception of reality is in many ways imagined. “Underneath our skull, everything is made up,” Lars Muckli, a professor of visual and cognitive neurosciences at the University of Glasgow, told me. “We entirely construct the world in its richness and detail and color and sound and content and excitement. … It is created by our neurons.”
To distinguish reality and imagination, the brain might have some kind of “reality threshold,” according to one theory. Researchers recently tested this by asking people to imagine specific images against a backdrop — and then secretly projected faint outlines of those images there. Participants typically recognized when they saw a real projection versus their imagined one, and those who rated images as more vivid were also more likely to identify them as real. The study suggested that when processing images, the brain might make a judgment on reality based on signal strength. If the signal is weak, the brain takes it for imagination. If it’s strong, the brain deems it real. “The brain has this really careful balancing act that it has to perform,” Thomas Naselaris, a neuroscientist at the University of Minnesota, told me. “In some sense it is going to interpret mental imagery as literally as it does visual imagery.”
Although recalling memories is a creative and imaginative process, it activates the visual cortex as if we were seeing. “It started to raise the question of whether a memory representation is actually different from a perceptual representation at all,” Sam Ling, a neuroscientist at Boston University, told me. A recent study looked to identify how memories and perceptions are constructed differently at the neurobiological level. When we perceive something, visual cues undergo layers of processing in the visual cortex that increase in complexity. Neurons in earlier parts of this process fire more precisely than those that get involved later. In the study, researchers found that during memory recall, neurons fired in a much blurrier way through all the layers. That might explain why our memories aren’t often as crisp as what we’re seeing in front of us…
“How Do Brains Tell Reality From Imagination?” from @yaseminsaplakoglu.bsky.social in @quantamagazine.bsky.social.
* Jean-Jacques Rousseau
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As we parse perception, we might send mindful birthday greetings to a man whose work figures into the history of science’s struggle on this issue, Franz Brentano; he was born on this date in 1838. A philosopher and psychologist, his 1874 Psychology from an Empirical Standpoint, considered his magnum opus and is credited with having reintroduced the medieval scholastic concept of intentionality into contemporary philosophy and psychology.
Brentano also studied perception, with conclusions that prefigure the discussion above…
He is also well known for claiming that Wahrnehmung ist Falschnehmung (‘perception is misconception’) that is to say perception is erroneous. In fact he maintained that external, sensory perception could not tell us anything about the de facto existence of the perceived world, which could simply be illusion. However, we can be absolutely sure of our internal perception. When I hear a tone, I cannot be completely sure that there is a tone in the real world, but I am absolutely certain that I do hear. This awareness, of the fact that I hear, is called internal perception. External perception, sensory perception, can only yield hypotheses about the perceived world, but not truth. Hence he and many of his pupils (in particular Carl Stumpf and Edmund Husserl) thought that the natural sciences could only yield hypotheses and never universal, absolute truths as in pure logic or mathematics.
However, in a reprinting of his Psychologie vom Empirischen Standpunkte (Psychology from an Empirical Standpoint), he recanted this previous view. He attempted to do so without reworking the previous arguments within that work, but it has been said that he was wholly unsuccessful. The new view states that when we hear a sound, we hear something from the external world; there are no physical phenomena of internal perception… – source
“Only in our speaking with one another does the world, as that about which we speak, emerge in its objectivity and visibility from all sides”*…
Blake Smith on trail-blazing publisher Michael Denneny and his embodiment of his mentor’s– Hannah Arendt‘s– thought…
Michael Denneny, the recently deceased co-founder and co-editor of the pioneering gay magazine Christopher Street , gay newspaper New York Native , and the gay publishing line at St. Martin’s Press, Stonewall Inn Editions, began his recently published collection of essays On Christopher Street with a quotation from his mentor, Hannah Arendt:
Only in our speaking with one another does the world, as that about which we speak, emerge in its objectivity and visibility from all sides. Living in a real world and speaking with one another about it are basically one and the same.
Denneny’s career as a gay cultural activist was a way of putting into practice Arendt’s thought as condensed in this citation…
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Arendt argued throughout her work, although with critically shifting emphases, that the possibility of political freedom for society as whole depends on particular groups within it being able to constitute distinct “worlds” in which their members can exchange perspectives, debate their common interests, and face the wider “world” composed of other groups. That is, a healthy society is diverse in the sense of being made up of individual units like economic classes and religious and ethnic minorities (represented by associations, trade unions, churches etc.), which are themselves characterized by internal diversity and lively debate.
Diversity and debate prevent, in a logic familiar from Montesquieu and Madison, the emergence of a single all-powerful leader or stifling consensus. In such accounts, which form the basis for American political common sense today, we imagine minorities as homogenous interest groups, which, in the play of their rival ambitions, keep each other in check, through a kind of balance of power akin to that at work in international relations. Politicized minorities, each pursuing its collective interests, can, if their debates and rivalries are properly channeled, be a force for good in politics.
Arendt’s argument is substantively different. In her account, minorities are important not insofar as they are internally unified groups engaged in the play of countervailing interests and powers, but rather insofar as they are internally heterogeneous groups whose very diversity offers a sort of school in which citizens learn how to have judgment: the capacity to express and exchange ideas without appeal to fixed rules. Differences within “our own groups”—our everyday experiences of debates with other people “like us” in the spaces of our associational life (synagogues, union halls, gay bars, etc.) prepare us for the still more challenging experiences of disagreement in our wider political life, where we cannot necessarily trust that our interlocutors share our identities, experiences, and goals.
Indeed, the experience of uncertainty is constitutive of politics, as Arendt saw it. Politics is one of a number of domains, she argued, in which we cannot call upon, in the course of our mutual questioning about what is to be done, anything like a logical principle (2+2=4) that all rational beings might recognize or a universally agreed-upon norm that all, or nearly all, members of our community do recognize. In these domains we are obligated to, as she often says, “woo” each other, to practice the arts of rhetorical seduction—which does not mean in her account, that we are in debates over politics merely practicing sophistry.
Rather, we are—as we find ourselves constantly doing in our most quotidian, non-political conversations—appealing to each other to share perspectives (Look!, we say, don’t you see?), on the assumption that each of us is positioned differently, because of our experiences, knowledge, interests, etc., in relation to a field of objects to which we all refer. We assume, in other words, that our divergent perspectives are perspectives on something, on the same things, and that we can by discussing them, inviting our interlocutors into our position by rendering it in speech, and projecting ourselves through our imaginations into their own positions, come closer to a true picture of the situation…
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…there is a danger that we may [Arendt argued], in the very exchange of perspectives, be speaking not at all to each other, that is, to specific interlocutors whose perspectives—and ultimately whose agreement—we desire (and thus whose disagreement we must tolerate), but rather to an abstract universal media pseudo-conversation, to the empty signifier of an invisible authority [and] one must admit that this peril characterizes our idle chatter on Twitter no less than the talk at cocktail parties and banal book reviews Arendt lamented in her day. In that sense it is not necessarily such a disaster if, for the moment, the possibility of a “national conversation” in media and politics seems to be suspended. Indeed, the whole point of Arendt and Denneny’s insight is to remind us that if we are to learn again how to speak to each other (and not merely speak in each other’s—perhaps merely virtual—presence), then participation in the life of real, concrete, internally diverse groups will be our classrooms…
Hannah Arendt, Michael Denneny, and the real value of diversity: “Living in Arendt’s World.”
* Hannah Arendt
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As we explore empathy, we might recall that it was on this date in 2015 that Cecilia Bleasdale sent her daughter Grace photo of a dress she intended to wear to Grace’s wedding. Celia thought that the dress, blue with black lace, would be perfect; but her daughter saw a white dress with gold lace. Grace posted the photo to Facebook, and the debate– blue/black or white/gold– broadened.
Then a friend uploaded it to Tumblr… and the argument went global. That post saw up to 840,000 views per minute. The next day, the retailer, Roman Originals (which confirmed that the dress was, in fact, blue and black), sold out of the model within 30 minutes.
It spread further. Celebrities posted and reposted, tweeted and retweeted (e.g., Taylor Swift, who saw blue and black and said she was “confused and scared,” was retweeted 111,134 times and liked 154,188 times); morning news shows covered the controversy…
Science has yet adequately to explain the phenomenon.
“Always remember that you are absolutely unique. Just like everyone else.”*…
We live, Taylor Orth reports, in a time in which everything is awful… for everyone else…
Ask Americans about life’s challenges, and you’ll find a common theme: They are, on average, a lot more positive about the state of their own lives than about the lives of everyone else in the country. In a recent experiment, YouGov asked Americans to rate 14 aspects of life on a scale from terrible to excellent. Respondents were divided into three randomly selected groups of equal size. Depending on the group, they were asked either about their own life, the lives of people in their local community, or the lives of people in the country at large.
At least half of Americans rate many aspects of their own life — including their healthcare, educational opportunities, social relationships, and employment situation — as either good or excellent. Positive ratings are somewhat less likely to be given by Americans evaluating people in their local area, and far less likely among those evaluating people in the U.S. as a whole.
The largest gap in ratings of one’s self compared to ratings of Americans overall is on mental health: People are 42 percentage points more likely to say their own mental health is excellent or good than they are to say so about people in the country as a whole. Gaps of 20 points or more are also found for positive ratings of one’s own versus the country’s personal safety (+31), physical health (+28), access to healthcare (+27), housing affordability (+25), and social relationships (+24)…
“More Americans have a positive outlook on their own lives than on their fellow Americans’,” from Taylor Orth at @YouGovAmerica.
Consider with: “Right-wing populist parties have risen. Populism hasn’t.” (“The success of these parties isn’t about a surge in populist sentiments…”)
* Margaret Mead
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As we ponder perspective, we might recall that it was on this date in 1997 that Lottie Williams became the first (and so far, only) human to be struck by a remnant of a space vehicle (a Delta II rocket, after it’s re-entry of the earth’s atmosphere).
Lottie Williams is strolling through a park in Tulsa, Oklahoma, when she sees a flash of light resembling a meteor. A short while later, she is struck on the shoulder by a piece of metal apparently from a disintegrating rocket, making her the only person believed to have been hit by a piece of space debris.
… NASA confirmed that the timing and location of the incident were consistent with the re-entry and breakup of a second-stage Delta rocket that fell to Earth after orbiting for several months. The main wreckage was recovered a couple of hundred miles away in Texas.
Williams was not injured. She was struck a glancing blow, and the debris was relatively light and probably traveling at a low velocity. It was also subject to wind currents, which mitigated the impact even further.
The amazing thing is that, given the amount of space junk that falls to Earth on a regular basis, there have been no other reports of someone being hit. Despite the veritable junkyard raining down on our planet — over a 40-year period roughly 5,400 tons of debris are thought to have survived re-entry into the atmosphere — the odds of actually being struck are infinitesimally small.
“Jan. 22, 1997: Heads Up, Lottie! It’s Space Junk!”
… The rest of the 260-kilogram tank, from which the fragment that hit her had come out, fell in Texas, near a farm. The piece was analyzed by researcher Winton Cornell of the University of Tulsa, who concluded that the material was used by NASA to insulate fuel tanks. The U.S. secretary of defense then sent a letter to Williams, apologizing for what happened…
“Lottie Williams, the Woman Who Was Hit by Space Junk”
“For what are myths if not the imposing of order on phenomena that do not possess order in themselves? And all myths, however they differ from philosophical systems and scientific theories, share this with them, that they negate the principle of randomness in the world.”*…
And we humans are, as Kit Yates explains, myth-making animals…
Unfortunately, when it comes to understanding random phenomena, our intuition often lets us down. Take a look at the image below. Before you read the caption, see if you can pick out the data set generated using truly uniform random numbers for the coordinates of the dots (i.e., for each point, independent of the others, the horizontal coordinate is equally likely to fall anywhere along the horizontal axis and the vertical coordinate is equally likely to fall anywhere along the vertical).
The truly randomly distributed points in the figure are those in the left-most image. The middle image represents the position of ants’ nests that, although distributed with some randomness, demonstrate a tendency to avoid being too close together in order not to overexploit the same resources. The territorial Patagonian seabirds’ nesting sites, in the right-most image, exhibit an even more regular and well-spaced distribution, preferring not to be too near to their neighbors when rearing their young. The computer-generated points, distributed uniformly at random in the left-hand image, have no such qualms about their close proximity.
If you chose the wrong option, you are by no means alone. Most of us tend to think of randomness as being “well spaced.” The tight clustering of dots and the frequent wide gaps of the genuinely random distribution seem to contradict our inherent ideas of what randomness should look like…
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… As a case in point, after noticing a disproportionate number of Steely Dan songs playing on his iPod shuffle, journalist Steven Levy questioned Steve Jobs directly about whether “shuffle” was truly random. Jobs assured him that it was and even got an engineer on the phone to confirm it. A follow-up article Levy wrote in Newsweek garnered a huge response from readers having similar experiences, questioning, for example, how two Bob Dylan songs shuffled to play one after the other (from among the thousands of songs in their collections) could possibly be random.
We ascribe meaning too readily to the clustering that randomness produces, and, consequently, we deduce that there is some generative force behind the pattern. We are hardwired to do this. The “evolutionary” argument holds that tens of thousands of years ago, if you were out hunting or gathering in the forest and you heard a rustle in the bushes, you’d be wise to play it safe and to run away as fast as you could. Maybe it was a predator out looking for their lunch and by running away you saved your skin. Probably, it was just the wind randomly whispering in the leaves and you ended up looking a little foolish—foolish, but alive and able to pass on your paranoid pattern-spotting genes to the next generation…
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This… is just one example of the phenomenon known in the psychology literature as pareidolia, in which an observer interprets an ambiguous auditory or visual stimulus as something they are familiar with. This phenomenon, otherwise known as “patternicity,” allows people to spot shapes in the clouds and is the reason why people think they see a man in the moon. Pareidolia is itself an example of the more general phenomenon of apophenia, in which people mistakenly perceive connections between and ascribe meaning to unrelated events or objects. Apophenia’s misconstrued connections lead us to validate incorrect hypotheses and draw illogical conclusions. Consequently, the phenomenon lies at the root of many conspiracy theories—think, for example, of extraterrestrial seekers believing that any bright light in the sky is a UFO.
Apophenia sends us looking for the cause behind the effect when, in reality, there is none at all. When we hear two songs by the same artist back-to-back, we are too quick to cry foul in the belief that we have spotted a pattern, when in fact these sorts of clusters are an inherent feature of randomness. Eventually, the dissatisfaction caused by the clustering inherent to the iPod’s genuinely random shuffle algorithm led Steve Jobs to implement the new “Smart Shuffle” feature on the iPod, which meant that the next song played couldn’t be too similar to the previous song, better conforming to our misconceived ideas of what randomness looks like. As Jobs himself quipped, “We’re making it less random to make it feel more random.”…
“Why Randomness Doesn’t Feel Random,” an excerpt from How to Expect the Unexpected: The Science of Making Predictions—and the Art of Knowing When Not To, by @Kit_Yates_Maths in @behscientist.
* Stanislaw Lem
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As we ponder purported patterns, we might send carefully-discerned birthday greetings to a man who did in fact find a pattern (or at least a meaning) in what might have seemed random and meaningless: Robert Woodrow Wilson; he was born on this date in 1936. An astronomer, he detected– with Bell Labs colleague Arno Penzias– cosmic microwave background radiation: “relic radiation”– that’s to say, the “sound “– of the Big Bang… familiar to those of us old enough to remember watching an old-fashioned television after the test pattern was gone (when there was no broadcast signal received): the “fuzz” we saw and the static-y sounds we heard, were that “relic radiation” being picked up.
Their 1964 discovery earned them the 1978 Nobel Prize in Physics.
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