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5 neuroscience reality checks, from a top neuroscientist
In his new book, The Deep History of Ourselves, Joseph LeDoux explains where we come from.

Brain sculpture is part of a piece titled 'Homage to Thomas Browne' at Hay Hill, Norwich, Norfolk, England, UK.
- In his latest book, neuroscientist Joseph LeDoux challenges current assumptions about emotions and consciousness.
- LeDoux investigates the origins of life on this planet dating back four billion years.
- His book is a reminder that humans share the planet with a diverse array of animals and that, while unique, consciousness is not the only trait worth celebrating.
In his new book, The Deep History of Ourselves: The Four-Billion-Year Story of How We Got Our Conscious Brains, neuroscientist Joseph LeDoux assigns himself the simple tasks of explaining how consciousness developed and redefining how we create and experience emotions.
Obviously, I'm being facetious. There's nothing simple about these tasks, yet in LeDoux's capable hands the reader is led, step by step, through the past four billion years of life on this planet. Consciousness, a phenomenon responsible for your ability to read and understand these words (as well as much, much more), often feels like a given, yet that's only because human life is short and evolution is so very long.
LeDoux writes about history splendidly. In his last book, Anxious (which I write about here and here), he investigates the development of nervous systems, entertaining the prospect that anxiety and fear are not innate physiological states but rather assembled experiences that can be sorted through and overcome. Throughout the book he overturns common assumptions about behavior and cognition.
Ditto Deep History. LeDoux writes that consciousness is "often a passive observer of behavior rather than an active controller of it." This conflicts with the assumption that every decision we make is of our own volition. He also argues that emotions "are cognitively assembled states of autonoetic consciousness," products of the same processes experienced via higher-order circuitry. Emotions are not separate from thoughts; they too are created in our nervous system by the same mechanisms.
From a 30,000-foot view, this makes sense. Humans did not arrive on the planet whole-cloth. We are constructed from parts that started self-assembling billions of years ago, the consequence of billions of years of chemistry, biology, and physiology. Deep History is an engrossing investigation of the human condition through the lens of ancient evolutionary history.
No single summation could suffice to cover this book's depth and complexity, nor should it—some arguments take time to unfold. Below are five fascinating passages pulled from the brain of one of the most thoughtful neuroscientists alive.
Survival precedes behavior.
It's easy to believe there's a reason for every action, yet reason comes after the survival instinct. Humans do many things for seemingly strange (or no) reason, only later attempting to explain the cognitive process that led to the action—filling in a psychological gap rather than actually defining the event. The mind likes to insert itself in places even—and especially—when it's late to the game.
"Behavior is not, as we commonly suppose, primarily a tool of the mind. Of course, human behavior can reflect the intentions, desires, and fears of the conscious mind. But when we go deep into the history of behavior, we can't help but conclude that it is first and foremost a tool of survival, whether in single cells or more complex organisms that have conscious control over some of their actions. The connection of behavioral to mental life is, like mental life itself, an evolutionary afterthought."
Neuroscience is, relatively speaking, still new.
It is common to assign certain brain regions as responsible for the creation and/or management of functions, which is a bit misleading. As far as neuroscience has advanced the field is still in its infancy. Brain scans track blood flow; that does not mean specific functions are limited to that region. (Of course, as LeDoux's friend and mentor, Michael Gazzaniga (listen to my interview with him here) has shown in his work in split-brain patients, localization does matter in certain regards; LeDoux even co-wrote a book with him on the topic.)
"Functions are not, strictly speaking, carried out by areas, or even by neurons in areas. They come about by way of circuits that consist of ensembles of neurons in one area that are connected by nerve fibers of axons to ensembles in other areas, forming functional networks. As with other features, the wiring pattern of sensory and motor systems is evolutionarily conserved across the vertebrates."
Don't get comfortable.
We like to believe ourselves to be separate from our environment. This is a false assumption. Life has always been about the interaction of species within their environment. Humans are no different. As everyone on the planet is experiencing the consequences, to varying degrees, of climate change, Darwinian fitness matters. Those trying to coast by on previous standards might find themselves in a rough situation.
"What works in a given environmental situation is determined by natural selection, but as the environment changes, or the group moves to a new niche, new traits become important and previously useful traits become detriments."
Pain is a state of mind.
LeDoux writes that pain and pleasure are often treated as emotions, but that's not quite true. There are no specific receptors for fear, joy, or anger. By contrast, certain receptors are activated when experiencing pain or pleasure, yet even those are subjective. For example, certain painful sensations are required for one person's erotic pleasure, while in others those same sensations might be translated as traumatic. Even chronic pain, it turns out, can be overridden at times.
"If a person with chronic pain is distracted by a funny joke, he does not experience the pain while laughing. The nociceptors are still responding, but the subjective pain is not noticed."
Humans are unique. So is every species.
Many people believe Homo sapiens represent the apex of the animal world. Some even believe we have a divine mandate to lord over other species. In reality, we are a quick blip in the long history of species. LeDoux points out factors that truly make humans unique—language, autonoesis, complex emotions. He also warns against the dangers of anthropocentrism and anthropomorphism. Fitness means adapting to the environment. Over the course of the last century we've arguably accomplished the opposite.
"Differences, while important in defining a species, do not endow some with greater value than others in the vast scheme of life. We may prefer the kind of life we lead, but in the end there is no scale, other than survivability, that can measure whether ours is a better or worse kind of life, biologically speaking, than that of apes, monkeys, cats, rats, birds, snakes, frogs, fish, bugs, jellyfish, sponges, choanoflagellates, fungi, plants, archaea, or bacteria. If species longevity is the measure, we will never do better than ancient unicellular organisms."
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Stay in touch with Derek on Twitter and Facebook. His next book is Hero's Dose: The Case For Psychedelics in Ritual and Therapy.
Scientists find 16 'ultra-black' fish species that absorb 99.9% of light
These alien-like creatures are virtually invisible in the deep sea.
A female Pacific blackdragon
- A team of marine biologists used nets to catch 16 species of deep-sea fish that have evolved the ability to be virtually invisible to prey and predators.
- "Ultra-black" skin seems to be an evolutionary adaptation that helps fish camouflage themselves in the deep sea, which is illuminated by bioluminescent organisms.
- There are likely more, and potentially much darker, ultra-black fish lurking deep in the ocean.
The Pacific blackdragon
Credit: Karen Osborn/Smithsonian
<p>When researchers first saw the deep-sea species, it wasn't immediately obvious that their skin was ultra-black. Then, marine biologist Karen Osborn, a co-author on the new paper, noticed something strange about the photos she took of the fish.</p><p style="margin-left: 20px;">"I had tried to take pictures of deep-sea fish before and got nothing but these really horrible pictures, where you can't see any detail," Osborn told <em><a href="https://www.wired.com/story/meet-the-ultra-black-vantafish/" target="_blank">Wired</a></em>. "How is it that I can shine two strobe lights at them and all that light just disappears?"</p><p>After examining samples of fish skin under the microscope, the researchers discovered that the fish skin contains a layer of organelles called melanosomes, which contain melanin, the same pigment that gives color to human skin and hair. This layer of melanosomes absorbs most of the light that hits them.</p>A crested bigscale
Credit: Karen Osborn/Smithsonian
<p style="margin-left: 20px;">"But what isn't absorbed side-scatters into the layer, and it's absorbed by the neighboring pigments that are all packed right up close to it," Osborn told <em>Wired</em>. "And so what they've done is create this super-efficient, very-little-material system where they can basically build a light trap with just the pigment particles and nothing else."</p><p>The result? Strange and terrifying deep-sea species, like the crested bigscale, fangtooth, and Pacific blackdragon, all of which appear in the deep sea as barely more than faint silhouettes.</p>Pacific viperfish
David Csepp, NMFS/AKFSC/ABL
<p>But interestingly, this unique disappearing trick wasn't passed on to these species by a common ancestor. Rather, they each developed it independently. As such, the different species use their ultra-blackness for different purposes. For example, the threadfin dragonfish only has ultra-black skin during its adolescent years, when it's rather defenseless, as <em>Wired</em> <a href="https://www.wired.com/story/meet-the-ultra-black-vantafish/" target="_blank">notes</a>.</p><p>Other fish—like the <a href="http://onebugaday.blogspot.com/2016/06/a-new-anglerfish-oneirodes-amaokai.html" target="_blank">oneirodes species</a>, which use bioluminescent lures to bait prey—probably evolved ultra-black skin to avoid reflecting the light their own bodies produce. Meanwhile, species like <em>C. acclinidens</em> only have ultra-black skin around their gut, possibly to hide light of bioluminescent fish they've eaten.</p><p>Given that these newly described species are just ones that this team found off the coast of California, there are likely many more, and possibly much darker, ultra-black fish swimming in the deep ocean. </p>'Deep Nostalgia' AI brings old photos to life through animation
Using machine-learning technology, the genealogy company My Heritage enables users to animate static images of their relatives.
- Deep Nostalgia uses machine learning to animate static images.
- The AI can animate images by "looking" at a single facial image, and the animations include movements such as blinking, smiling and head tilting.
- As deepfake technology becomes increasingly sophisticated, some are concerned about how bad actors might abuse the technology to manipulate the pubic.
My Heritage/Deep Nostalgia
<p>But that's not to say the animations are perfect. As with most deep-fake technology, there's still an uncanny air to the images, with some of the facial movements appearing slightly unnatural. What's more, Deep Nostalgia is only able to create deepfakes of one person's face from the neck up, so you couldn't use it to animate group photos, or photos of people doing any sort of physical activity.</p>My Heritage/Deep Nostalgia
<p>But for a free deep-fake service, Deep Nostalgia is pretty impressive, especially considering you can use it to create deepfakes of <em>any </em>face, human or not. </p>When does an idea die? Plato and string theory clash with data
How long should one wait until an idea like string theory, seductive as it may be, is deemed unrealistic?
- How far should we defend an idea in the face of contrarian evidence?
- Who decides when it's time to abandon an idea and deem it wrong?
- Science carries within it its seeds from ancient Greece, including certain prejudices of how reality should or shouldn't be.
Plato used the allegory of the cave to explain that what humans see and experience is not the true reality.
Credit: Gothika via Wikimedia Commons CC 4.0
<p>When scientists and mathematicians use the term <em>Platonic worldview</em>, that's what they mean in general: The unbound capacity of reason to unlock the secrets of creation, one by one. Einstein, for one, was a believer, preaching the fundamental reasonableness of nature; no weird unexplainable stuff, like a god that plays dice—his tongue-in-cheek critique of the belief that the unpredictability of the quantum world was truly fundamental to nature and not just a shortcoming of our current understanding. Despite his strong belief in such underlying order, Einstein recognized the imperfection of human knowledge: "What I see of Nature is a magnificent structure that we can comprehend only very imperfectly, and that must fill a thinking person with a feeling of humility." (Quoted by Dukas and Hoffmann in <em>Albert Einstein, The Human Side: Glimpses from His Archives</em> (1979), 39.)</p> <p>Einstein embodies the tension between these two clashing worldviews, a tension that is still very much with us today: On the one hand, the Platonic ideology that the fundamental stuff of reality is logical and understandable to the human mind, and, on the other, the acknowledgment that our reasoning has limitations, that our tools have limitations and thus that to reach some sort of final or complete understanding of the material world is nothing but an impossible, <a href="https://www.amazon.com/dp/B01K2JTGIA?tag=bigthink00-20&linkCode=ogi&th=1&psc=1" target="_blank" rel="noopener noreferrer">semi-religious dream</a>.</p>Can you still spread coronavirus after getting the vaccine?
The vaccine will shorten the "shedding" time.
