Visiting the “World Behind the World”

Musings

I’m a bit late to the party–it’s hard to shop for English language books here in Germany–but I finally read Erik Hoel’s 2023 book on the science of consciousness: The World Behind the World. Well, this world between the book covers is fantastic. I’m not here so much to review Hoel’s book–which anyone interested in the mind and consciousness should buy–so much as I’m here to celebrate some of its gems while also responding to some of its bolder claims.

Two perspectives

The book begins by establishing the intellectual development of humanity’s two perspectives: the subjective and the objective, or the intrinsic and extrinsic perspectives, respectively. There’s much surprising territory here. Remember how a few years ago, the internet started buzzing with stories about how some ancient cultures didn’t have a word for the color blue? Well, long before this was trendy, Princeton University psychologist and author Julian Jaynes speculated that ancient people didn’t even have an intrinsic perspective in the same way that we do, as characters in many ancient myths and poems generally lack internal dialogue or much of an inner life. Hoel and I both find the strong version of this argument silly: Homo sapiens were obviously conscious before innovations in culture and literature revealed deeper characters with internal experiences, despite Jaynes’ claims to the contrary in his 1976 book The Origin of Consciousness in the Breakdown of the Bicameral Mind. However, a more plausible idea stemming from Jaynes’ work is that human beings simply did not thoroughly develop the concept of an intrinsic perspective, on an intellectual and artistic level, until cultural developments which occurred perhaps a couple of thousand years ago (for example, in Greek theater). My own take on this, which I think departs a bit from Hoel’s, is that ancient people were perhaps more likely to recognize the nondual nature of consciousness, acknowledged in traditions such as Buddhism and Advaita; that is, they had not yet constructed an ego that sits on consciousness, observing the outside world from the inside. This is possibly supported by Jaynes’ observation, retold by Hoel, that some ancient cultures interpreted thoughts as “the commandments of the gods”, having a hallucinatory quality. Such detachment from thought might sound like mental illness to you, but similar experiences are regarded as enlightenment in some Eastern schools of philosophy and religion.

From here, Hoel takes us through the story of the intrinsic perspective from both a literary and scientific perspective, as only a novelist and neuroscientist can. This story brings us to contemporary theories and thought experiments that illuminate the intrinsic perspective. Even if you’re a scholar of consciousness like me, there are many delightful gems to be found here. For instance, you might already know about David Chalmer’s zombie thought experiment–is a world conceivable in which everyone behaves exactly the same way but lacks consciousness? I’ve read much about this thought experiment over the years: if you find this scenario conceivable, then it seems that a materialistic account of the universe is incomplete, as you cannot derive consciousness from physical laws (after all, everything is physically identical between our universe and the zombie universe). However, there’s a particular glitch here that’s long dampened the conceivability of the zombie world for me: how could zombies possibly talk about consciousness? Before reading Hoel’s book, I only knew of this glitch from Chalmer’s appearance on Sam Harris’s podcast, which I’ve written about elsewhere. But Hoel takes this very meta perspective on the zombie argument much further in the chapter “The Tale of Zombie Descartes”. I won’t spoil the fun, but if you like paradoxes, this is your kind of book.

Another absolute gem for me is Hoel’s analogy between the inaccessibility of consciousness, an inherently private phenomenon, to the inaccessibility of the inside of a black hole in the chapter “Phenomenological Theories of Consciousness”. Though Hoel doesn’t make this next point explicitly, it seems straightforward then to argue that psychologists and neuroscientists studying consciousness are legitimate scientists just as cosmologists and physicists studying the inside of black holes are legitimate scientists. Both are peering behind the curtain of observability, into a space that no instrument can directly measure, and even while some of their predictions cannot be tested, enough testable predictions remain that their theories are overall falsifiable.

The World Behind the World tells the story of two perspectives, the extrinsic and the intrinsic.

Why do we need a theory of consciousness?

Much of Hoel’s book is focused on why we need a theory of consciousness. Overall, I couldn’t agree more that we need such a theory. We also agree that it’s unwise to label ambitious theories of consciousness as pseudoscience, a response to developments soon after Hoel’s book was published, and that introspection should play a larger role in neuroscience–the intrinsic perspective must be accounted for alongside the extrinsic perspective if we want to understand the mind. However, Hoel and I disagree slightly on the scope of this issue. In his words echoing biologist Theodosius Dobzhansky, “Nothing in the brain makes sense except in the light of consciousness.” I, on the other hand, think the brain generally makes plenty of sense without consciousness (hence, the zombie thought experiment). Whereas Hoel believes that brains evolved for consciousness, I think it’s straightforward to argue that the brain evolved for motor coordination and movement–everything else is just a nice bonus that came later. Consider, for instance, that many small insects, like fruit flies, obviously have a brain but are not obviously conscious (they might be, but their brains make plenty of sense without consciousness). Moreover, many parts of the human brain, such as the cerebellum (which contains most of the brain’s neurons) and the basal ganglia are heavily involved in motor functions but play little if any role in consciousness. Of course, that observation is itself useful for understanding consciousness; consciousness researchers need neuroscience, but not all neuroscientists need consciousness research.

Because we cannot understand consciousness, the very thing that Hoel believes brains evolved for, he views neuroscience as an immature science lacking fundamental principles (that is, the field is “pre-paradigmatic”). Besides dedicating an entire chapter of his book to this issue, Hoel has also summarized his views in an online essay (I’ll be reflecting on this chapter in a later post). While I’m not convinced that we always need to put subjective experience (the intrinsic perspective) first to understand the brain (the extrinsic perspective), one area where this approach makes perfect sense to me is our quest to understand dreaming. Neuroscientists still have virtually no idea why we dream each night, and Hoel’s “overfitted brain hypothesis” from 2021 is a brilliant use of the phenomenology first approach. In a research paper published in the journal Patterns, Hoel has put forth the most convincing theory of dreaming I’ve ever encountered: dreams and their bizarre phenomenology are necessary for us to learn to generalize from our daily experiences to novel situations. Even if neuroscience isn’t preparadigmatic, the field of dream research certainly was, in my view, until Hoel’s theory.

Erik Hoel is also the author of a novel titled The Revelations

Does free will exist?

Despite my nitpicking, Hoel and I generally agree on more things than we disagree. The only place where I found area where I firmly diverge from Hoel’s perspective is the book’s last chapter, “The Scientific Case for Free Will”. Here, Hoel argues that humans have free will because of emergent causation. This concept tells us that brains and behavior cannot always be reduced to the microscopic level of individual cells, for many microscopic brain states correspond to the same mental state or behavior. I agree that the correct spatial scale to study the brain isn’t always the firing of single cells. I even agree with Hoel that Benjamin Libet’s famous prediction of volitional decisions from earlier brain activity isn’t really a knockout blow to free will. But I also don’t think we even need neurobiology to see that free will doesn’t make sense. And since Hoel’s argument for free will is really the climax of the book, I feel some need to respond to it.

To give my perspective, I’ll paraphrase Sam Harris, who also views neuroscience as a distraction for understanding the illusion of free will. Let’s suppose reductionism is false. Let’s even suppose, just for the sake of argument, that you believe in a soul. A person born with a good soul or an evil soul isn’t free; they didn’t create themselves or their soul. They aren’t responsible for their personality, their likes and dislikes, their preferences, their decisions, or anything about themselves. Even if they read self-help books and “choose” radical self-improvement, that decision is still caused by interactions between their character and their environment. You don’t need neuroscience to see any of this, though the details just become more material and obvious when you do. When you substitute large neural populations at the relevant spatial scale for a human soul, nothing actually changes.

Finally, Hoel argues that viewing free will as an illusion is bad for us, citing a 2016 study by Crescioni and colleagues which reported, in Hoel’s words, that “the belief in free will has been correlated with … a greater tendency to forgive”. I have a very different intuition – if I believe that someone who has wronged me could have done otherwise, why would I be more likely to forgive them? So I looked into the literature and found that a 2023 metaanalysis which included the study in question, alongside over a hundred other studies, found no evidence for these negative psychological effects stemming from free will skepticism. Like Sam Harris, I think that relinquishing the belief in free will is far from nihilistic and likely has a net positive effect on our ethics: we are more likely to feel compassion for others, as they couldn’t have done differently, and more likely to feel connected to the world around us, as we don’t exist as a separate free agent outside its causal structure. In other words, it relaxes another illusion, the illusion of self.

Unlike Erik Hoel, Sam Harris (host of the Making Sense podcast and a book of conversations with the same title) argues that free will is an illusion.

Conclusion

For me, The World Behind the World offers just the right balance of material to agree and disagree with to make it an exceptionally enjoyable read (after all, too much of either is boring). I hope Hoel writes more books in the near future, and in the meanwhile, I’ll be reading his novel, The Revelations, and continuing to follow his Substack newsletter, The Intrinsic Perspective.

Stella Dorrestein (pictured) is a medical doctor currently pursuing a PhD in psychopharmacology at the Centre for Human Drug Research in Leiden, the Netherlands while researching new drugs for psychiatric disorders. She is interested in psychedelic substances like DMT and ketamine which are receiving thorough investigation for their potential applications in treating conditions such as depression, with promising results.

Writing and photos by Joel Frohlich.

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Empathy from Dissimilarity In Neural Responses To Touch and Pain

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Lulla, R., Christov-Moore, L., Vaccaro, A., Reggente, N., Iacoboni, M., & Kaplan, J. (2024). Empathy from Dissimilarity: Multivariate Pattern Analysis of Neural Activity During Observation of Somatosensory Experience. Imaging Neuroscience. https://doi.org/10.1162/imag_a_00110

Lulla, Rishi, et al. “Empathy from Dissimilarity: Multivariate Pattern Analysis of Neural Activity During Observation of Somatosensory Experience.” Imaging Neuroscience, Jan. 2024, doi:10.1162/imag_a_00110.

@article{Lulla_Christov-Moore_Vaccaro_Reggente_Iacoboni_Kaplan_2024, title={Empathy from Dissimilarity: Multivariate Pattern Analysis of Neural Activity During Observation of Somatosensory Experience}, url={https://doi.org/10.1162/imag_a_00110}, DOI={10.1162/imag_a_00110}, journal={Imaging Neuroscience}, author={Lulla, Rishi and Christov-Moore, Leonardo and Vaccaro, A. and Reggente, Nicco and Iacoboni, Marco and Kaplan, Jonas}, year={2024}, month=jan }

Empathy: A Deeper Look

Empathy involves both understanding and sharing in the states of others. It’s been relatively established that empathy is related to our ability to simulate and internalize another’s experience as if it is happening to us, referred to as the ‘simulationist’ theory of empathy. However, how these simulations translate into empathic ability remains unclear. In an article titled ‘Empathy from Dissimilarity: Multivariate Pattern Analysis of Neural Activity during Observation of Others’ Somatosensory States’, researchers from the University of Southern California and the Institute for Advanced Consciousness Studies investigate the relationship between internal simulations and empathic traits. They question whether the importance of these simulations depends on not only the strength of the simulation but more so the distinguishability across simulated states.

Brain Patterns and Simulation

To evaluate this theory using patterns of neural activity, researchers recruited 70 healthy participants to undergo MRI imaging while observing videos intended to simulate certain sensory states. The videos consisted of a hand experiencing painful and tactile stimulation and a hand in isolation as control. They used advanced multivariate analysis techniques to delve into the granularity of neural activity, such as differences in neural patterns when simulating pain versus touch. This allowed them to probe whether the key to the simulationist theory lay within the relationship between differences in neural patterns of simulated states and empathic ability.

Dissimilarity as a Key Factor

This article evaluates empathy through the lens of ‘pattern dissimilarity’ rather than overall activation during observed experiences of others, analyzing areas of the brain in which pattern dissimilarity was predictive of empathic traits. This proved to be more useful than traditional methods of evaluating neural responses that rely on average activation levels rather than activity patterns. Researchers discovered that pattern dissimilarity was predictive of empathic traits in the same areas of the brain that would be engaged if the participant was experiencing the observed stimulation themselves. This sheds light on the intricacies of somatosensation, our bodily perception of the senses, that contribute to empathic ability.

Implications for Understanding Empathy

These findings show how pattern dissimilarity may provide deeper information than traditional analysis methods when researching cognitive functions such as empathy. Researchers suggest that the distinguishability of simulated internal states in somatosensory areas of the brain is predictive of an individual’s sympathetic reactions to the distress of others. Perhaps it’s not only the level of brain activity during internal simulation, but more so the uniqueness and distinguishability of that brain activity that leads us to feel for and understand others.

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The neural correlates of chills: How bodily sensations shape emotional experiences

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Schoeller, F., Jain, A., Pizzagalli, D. A., & Reggente, N. (2024). The neurobiology of aesthetic chills: How bodily sensations shape emotional experiences. Cognitive, Affective, & Behavioral Neuroscience. https://doi.org/10.3758/s13415-024-01168-x

Schoeller, Félix, Abhinandan Jain, et al. “The neurobiology of aesthetic chills: How bodily sensations shape emotional experiences.” Cognitive, Affective, & Behavioral Neuroscience, Feb. 2024, doi:10.3758/s13415-024-01168-x.

@article{Schoeller_Jain_Pizzagalli_Reggente_2024, title={The neurobiology of aesthetic chills: How bodily sensations shape emotional experiences}, url={https://doi.org/10.3758/s13415-024-01168-x}, DOI={10.3758/s13415-024-01168-x}, journal={Cognitive, Affective, & Behavioral Neuroscience}, author={Schoeller, Félix and Jain, Abhinandan and Pizzagalli, Diego A. and Reggente, Nicco}, year={2024}, month=feb }

Neural Correlates of Chills: How the Brain Creates a Powerful Emotional Response

Aesthetic chills are a universal emotional response characterized by shivers and goosebumps in reaction to specific rewarding or threatening stimuli, such as music, films, or speech. What makes this phenomenon so intriguing is that it simultaneously involves subjective feelings and measurable physical sensations, providing a tangible link between the mind and body.

The Role of Brain Regions and Networks

Recent research has shed light on the specific brain regions and networks involved in the experience of aesthetic chills. Understanding the neural correlates of chills helps us delve into fascinating questions about the mind-body connection.

Our review highlights key questions that aesthetic chills can help us answer: How precisely do bodily sensations influence emotional experiences? What is the role of prediction and uncertainty in shaping our feelings? And how does the brain balance processing rewards versus threats?

neural correlates of chills are vast and span the cerebrum, cerebellum, and brainstem

The Mesocorticolimbic System: A Key Player in Chills

By synthesizing evidence from neuroimaging studies, we propose that aesthetic chills engage a distinct brain network involving the mesocorticolimbic system. This network includes regions like the ventral tegmental area (VTA), nucleus accumbens (NAcc), amygdala (AMG), and frontal areas such as the orbitofrontal cortex (OFC) and ventromedial prefrontal cortex (vmPFC). Crucially, the VTA releases dopamine, a neurotransmitter critical for reward processing and motivation, throughout these regions.

Chills, Reward, Learning, and the Brain’s Predictions

neural correlates of chills seem to depend on the learning rate

We suggest that aesthetic chills may correspond to peaks in consummatory pleasure, marking the transition from the “wanting” phase of reward to the “liking” and “learning” phases. This perspective aligns with the observation that chills often occur during the culmination of an aesthetic experience, such as the resolution of a narrative or musical tension.

neural correlates of chills seem associated with the anticipation and reward response.

Interoception and the Insula

The involvement of the insula, a region linked to interoception (the perception of internal bodily states), highlights the importance of peripheral signals in shaping the emotional quality of chills. This is further supported by findings that manipulating bodily sensations, such as enhancing the feeling of cold, can intensify the experience of chills and its downstream effects on cognition.

Individual Differences and the Experience of Chills

Interestingly, our susceptibility to aesthetic chills seems to be influenced by individual differences in personality traits like openness to experience and absorption, as well as biological factors such as gene variants affecting neurotransmitter function. This suggests that our propensity for chills is shaped by a complex interplay of psychological and neurobiological factors.

Dopamine, Prediction Errors, and Learning

We propose that the neurotransmitter dopamine plays a key role in aesthetic chills by encoding the precision of our brain’s predictions. When an aesthetic stimulus violates our expectations in a way that is ultimately rewarding, dopamine release signals the need to update our predictions, enhancing memory consolidation and learning. This process may underlie the heightened attention and memory effects observed during chills.

Mental Health Implications

Understanding the neurobiology of aesthetic chills has important implications for mental health. Dysfunctional precision encoding of prediction errors by dopamine is implicated in conditions like schizophrenia, depression, and addiction. Preliminary evidence suggests that experiencing aesthetic chills may help mitigate anhedonia (loss of pleasure) in depression by improving reward learning and shifting maladaptive self-beliefs. The therapeutic potential of chills lies in their ability to promote positive emotional states and cognitive flexibility.

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Predicting Chills – Characterizing Individual Differences in Peak Emotional Response

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Schoeller, F., Christov-Moore, L., Lynch, C., Diot, T., & Reggente, N. (2024). Predicting Individual Differences in Peak Emotional Response. PNAS Nexus, 3(3). https://doi.org/10.1093/pnasnexus/pgae066

Schoeller, Félix, Leonardo Christov-Moore, et al. “Predicting Individual Differences in Peak Emotional Response.” PNAS Nexus, vol. 3, no. 3, Feb. 2024, https://doi.org/10.1093/pnasnexus/pgae066.

@article{Schoeller_Christov-Moore_Lynch_Diot_Reggente_2024, title={Predicting Individual Differences in Peak Emotional Response}, volume={3}, url={https://doi.org/10.1093/pnasnexus/pgae066}, DOI={10.1093/pnasnexus/pgae066}, number={3}, journal={PNAS Nexus}, author={Schoeller, Félix and Christov-Moore, Leonardo and Lynch, Caitlin and Diot, Thomas and Reggente, Nicco}, year={2024}, month=feb }

Predicting Chills: Unraveling the Factors Behind a Powerful Emotional Response

Have you ever felt a shiver run down your spine when deeply moved by a piece of music or a scene in a film? Those “aesthetic chills” offer a fascinating glimpse into the interplay of our emotions and our individual experiences. In a recent study published in PNAS Nexus, we aimed to understand what makes some people more likely to feel these chills.

The Study Design

Our approach was multifaceted:

  • Stimuli Selection: We used innovative data mining techniques on social media platforms to curate a database of stimuli with a proven track record of inducing chills.
  • Diverse Participants: We exposed a diverse group of over 2,900 participants from Southern California to these stimuli. Data on their demographics, personality traits, and emotional responses were carefully collected.

Key Findings: Who’s Most Likely to Experience Chills

Our results were illuminating:

  • Demographics: Certain demographic factors, such as being middle-aged, highly educated, and male, were associated with a greater likelihood of experiencing chills.
  • Personality’s Impact: We also identified specific personality traits, like extraversion and conscientiousness, that were linked to more intense chills responses.
  • Microcultures and Resonance: Perhaps the most intriguing finding was the use of latent class analysis to uncover hidden “microcultures.” These subgroups, characterized by specific combinations of demographic and psychological attributes, were significantly more likely to experience chills. This points to the role of cultural resonance in shaping these emotional experiences.
predicting chills is hard - this image shows a bunch of people in a where's waldo style backdrop all looking at different pieces of content

Predictive Power: Can We Foresee Chills?

We pushed the analysis further by employing machine learning algorithms to see if we could predict the occurrence and intensity of chills based on a combination of personal characteristics. Our models achieved up to 73.5% accuracy in predicting whether someone would experience chills and accounted for 48% of the variance in chills intensity.

The Significance of Our Work

This study has far-reaching implications. By identifying the key factors that shape our susceptibility to aesthetic chills, we open doors to more targeted and personalized approaches to studying these experiences in a laboratory setting. Furthermore, understanding these “chills profiles” could pave the way for using music, art, or other stimuli in therapeutic contexts – perhaps helping reduce symptoms like anhedonia in depression.

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individual differences in aesthetic chills

Individual Differences in Aesthetic Chills

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Schoeller, F., Moore, L., Lynch, C., & Reggente, N. (2023c). ChillsDB 2.0: Individual Differences in aesthetic chills among 2,900+ Southern California participants. Scientific Data, 10(1). https://doi.org/10.1038/s41597-023-02816-6

Schoeller, Felix, et al. “ChillsDB 2.0: Individual Differences in Aesthetic Chills Among 2,900+ Southern California Participants.” Scientific data 10.1 (2023): 922.

@article{schoeller2023chillsdb, title={ChillsDB 2.0: Individual Differences in Aesthetic Chills Among 2,900+ Southern California Participants}, author={Schoeller, Felix and Christov Moore, Leo and Lynch, Caite and Reggente, Nicco}, journal={Scientific data}, volume={10}, number={1}, pages={922}, year={2023}, publisher={Nature Publishing Group UK London} }

Understanding Individual Differences in Aesthetic Chills

At IACS, we have been deeply engaged in the scientific exploration of aesthetic chills – those spine-tingling, goosebump-inducing responses evoked by stimuli such as music, films, and stories at large. These responses are recognized as a universal indicator of peak human experiences that transcend cultural boundaries.

Tools for Investigating Aesthetic Chills

One of our main goals is to build an open-source technological infrastructure for researchers to study chills in the lab. Our first output was ChillsDB, a database of audiovisual stimuli designed and validated to reliably induce aesthetic chills in a laboratory setting. This tool represented a breakthrough for the field, enabling researchers to investigate the psychological and neurological foundations of this intense emotional response under controlled conditions.

individual differences in aesthetic chills - this image shows a person viewing different pieces of content to emphasize how different people get chills from different content.

ChillsDB 2.0: Focusing on Individuality

We are now excited to announce the release of ChillsDB 2.0, published in Nature: Scientific Data, which marks a significant expansion of our initial efforts. In this updated version, we have enriched our dataset with inputs from nearly 3,000 diverse participants from Southern California. This enhancement not only includes responses to a selection of stimuli from our original database and new additions but also encompasses comprehensive data on participants’ demographics, personality traits, and emotional states before and after exposure to each stimulus.

The Therapeutic Potential of Aesthetic Chills

ChillsDB 2.0 has already proven to be a foundational resource for examining the therapeutic possibilities of aesthetic chills in treating conditions like depression. By elucidating the mechanisms behind these peak emotional states, we aim to discover novel methods for enhancing mood and introducing new perspectives to both clinical and general populations.

The Path Forward

While significant efforts are still required to comprehensively understand the phenomenology and neurobiology of aesthetic chills and to harness these insights for improving well-being, this new database represents an important step forward.

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fetal brain complexity decreases at birth

Surprising new research reveals how fetal brain complexity declines before and after birth

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Frohlich, J., Moser, J., Sippel, K., Mediano, P. a. M., Preissl, H., & Gharabaghi, A. (2024). Sex differences in prenatal development of neural complexity in the human brain. Nature Mental Health. https://doi.org/10.1038/s44220-024-00206-4

Frohlich, Joel, Julia Moser, Katrin Sippel, et al. “Sex differences in prenatal development of neural complexity in the human brain.” Nature Mental Health, Feb. 2024, doi:10.1038/s44220-024-00206-4.

@article{Frohlich_Moser_Sippel_Mediano_Preissl_Gharabaghi_2024, title={Sex differences in prenatal development of neural complexity in the human brain}, url={https://doi.org/10.1038/s44220-024-00206-4}, DOI={10.1038/s44220-024-00206-4}, journal={Nature Mental Health}, author={Frohlich, Joel and Moser, Julia and Sippel, Katrin and Mediano, Pedro a. M. and Preissl, Hubert and Gharabaghi, Alireza}, year={2024}, month=feb }

Fetal Brain Complexity: New Research Challenges Expectations

Even as birth nears, the complexity of brain activity decreases with fetal maturation and continues to decline after birth, according to results recently published in Nature Mental Health by a research team with key contributors from the University of Tuebingen, Germany and led by Dr. Joel Frohlich, who also serves as a research consultant for the Institute for Advanced Consciousness Studies in addition to his postdoctoral position in Tuebingen.

Sex Differences in Fetal Brain Development: A Surprising Finding

More surprising still, male and female fetuses show different changes in complexity, with boys declining faster than girls. According to the authors, the study’s findings carry important implications for future efforts to develop predictive biomarkers of psychiatric disorders based on the complexity of brain activity recorded before birth.

Investigating Fetal Brain Activity with MEG

The published manuscript, titled “Sex differences in prenatal development of neural complexity in the human brain”, was sparked by a two-year interdisciplinary collaboration between the laboratories of University of Tuebingen professors Alireza Gharabaghi and Hubert Preissl, with Frohlich serving liaison between the respective labs. Prof. Gharabaghi leads Tuebingen’s Institute for Neuromodulation and Neurotechnology, whose mission to develop new brain stimulation techniques led the institute to consider how sensory stimulation could be safely applied to investigate neural integrity in fetuses and infants, much in the same manner as electromagnetic brain stimulation is currently used in adults. When the collaboration began, Prof. Preissl, director of Tuebingen’s fMEG Center, had already supervised relevant experiments conducted by Dr. Julia Moser (now at the University of Minnesota) and Dr. Katrin Sippel, which gave the team the data they were looking for.

Fetal brain activity has already revealed evidence of learning before birth

The team used magnetoencephalography or MEG (a technology for detecting weak magnetic activity in the brain) to record neural signals non-invasively from third trimester fetuses and newborns. These signals were responses to sequences of auditory tones, which included patterns that were occasionally broken to test if fetuses (and, later, newborn infants) had successfully learned the original sequence. Two earlier research manuscripts, led by Moser, examined these data in the context of fetal and newborn learning and revealed evidence that fetuses respond to pattern violations as early as 35 weeks gestation, late in the third trimester of pregnancy. “Sensory stimulation provides us with a unique opportunity to observe how young brains process information from the outside. And all in a completely safe way,” explained Prof. Preissl in a recent press release.

In the current manuscript, the research team then applied several different algorithms to estimate the complexity of the MEG signals using entropy, or the number of possible ways in which states of the signal can be arranged. Some of these algorithms work by determining how difficult it is to compress the signal, as more complex data are harder to compress. To understand this better, consider the compressed size of two image files on your computer, one depicting a Vermeer painting and the other depicting a Rothko painting. The more complex image (Vermeer) will be harder to compress into a small file. Similarly, more complex brain signals are harder to compress, allowing scientists to estimate their entropy.

A pregnant woman positioning the fetus into the MEG.

Surprising results from fetal brain activity

The researchers originally hypothesized that fetal brain activity would grow more complex with maturation. To their surprise, the opposite occurred. “Intuitively, I had thought that as the brain matures, its activity should grow more complex just as its anatomy and function grows more complex,” said Frohlich. “In hindsight though, it makes a decent amount of sense, especially considering the fact that we recorded brain activity evoked by sensory signals, rather than spontaneous activity.” As the brain develops, it moves away from random patterns toward more ordered modes of activity sculpted by emerging synaptic connections. These connections constrain the number of ways in which the brain can respond to stimuli such as the auditory patterns in the experiment. This is likely why more mature fetal brains showed less complex activity in their responses: these brains had fewer ways of responding to the same stimulus, and thus lower complexity. According to Frohlich, if the experiment had instead looked at spontaneous brain activity in the absence of stimuli, the results might have been different.

Crucial to the team’s conclusions were contributions from Imperial College London professor Pedro Mediano, who shared a sophisticated mathematical algorithm which allowed the team to determine which properties of the fetal brain signals were driving the decrease in their complexity. Using Mediano’s approach, the team found that changes in the amplitude or “strength” of the signal were related to the decreasing complexity. In fact, the effect of amplitude appeared to mask changes caused by another property of the signal, phase, which opposed complexity by driving increases in complexity with maturation. The presence of two opposing processes might partially explain the team’s surprising results with respect to maturation.

However, the effects of fetal sex are still leaving the team slightly puzzled. “I didn’t expect fetal sex to have any impact on neural complexity,” said Frohlich, “but it’s possible that this relates to the greater vulnerability of the male brain during gestation, as many neurodevelopmental disorders, like autism and ADHD, are diagnosed more frequently in boys.” Frohlich is inspired by earlier studies that have linked the complexity of neural activity to brain health, including one previous study which predicted the onset of autism years later from brain activity recorded in young infants. Neurodevelopmental disorders such as autism are best prevented very early in life while the brain is still highly plastic, which creates a need for early detection of risk. “The earlier we identify the risk of developing neuropsychiatric and metabolic disorders, the more effectively we can support brain development to prevent serious illness,” explained Prof. Gharabaghi in a press release.

Looking toward the future

According to Frohlich, whose 2018 PhD dissertation focused on biomarkers of neurodevelopmental disorders, the next step in this line of work will be to follow fetuses several years after birth to see whether the complexity of their fetal brain activity predicts later outcomes such as autism or ADHD. “For example, you could recruit pregnant women who already have a child with autism, which means that the fetus has some familial risk of also developing it. By recording brain activity from the fetus and then following up with the family three years later, you could see if the complexity of prenatal brain activity is predictive of an eventual diagnosis.”

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is cannabis psychedelic? Kind of!

Is Cannabis Psychedelic?

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Murray, C. H., Frohlich, J., Haggarty, C. J., Tare, I., Lee, R., & De Wit, H. (2024). Neural Complexity Is Increased After Low Doses of LSD, but Not Moderate to High Doses of Oral THC or Methamphetamine. Neuropsychopharmacology. https://doi.org/10.1038/s41386-024-01809-2

“Neural Complexity Is Increased After Low Doses of LSD, but Not Moderate to High Doses of Oral THC or Methamphetamine.” Neuropsychopharmacology, Jan. 2024, doi:10.1038/s41386-024-01809-2.

@article{Murray_Frohlich_Haggarty_Tare_Lee_De Wit_2024b, title={Neural Complexity Is Increased After Low Doses of LSD, but Not Moderate to High Doses of Oral THC or Methamphetamine}, url={https://doi.org/10.1038/s41386-024-01809-2}, DOI={10.1038/s41386-024-01809-2}, journal={Neuropsychopharmacology}, author={Murray, Conor H. and Frohlich, Joel and Haggarty, Connor J. and Tare, Ilaria and Lee, Royce and De Wit, Harriet}, year={2024}, month=jan }

Cannabis and the Psychedelic: A Historical Perspective

In 1857, the American writer Fitz Hugh Ludlow described his experiences with hashish in his memoir The Hasheesh Eater: Being Passages from the Life of a Pythagorean:

“It is this process of symbolization which, in certain hasheesh states, gives every tree and house, every pebble and leaf, every footprint, feature, and gesture, a significance beyond mere matter or form, which possesses an inconceivable force of tortures or of happiness.”

Delving into Terminology: What Does “Psychedelic” Really Mean?

For Ludlow, hashish infused meaning into everyday objects; his experiences seemed to reveal new parts of the mind, with either blissful or terrifying effects. In 1956, the psychiatrist Humphrey Osmond coined a term to encapsulate such “mind-manifesting” phenomena: psychedelic. Both then and now, the term is mostly applied to drugs like LSD that powerfully alter one’s perception through their action at a specific neurotransmitter receptor called 5HT2a, which receives signals from serotonin, one of the brain’s main chemical messengers. These “classic psychedelics” have a very different pharmacology than tetrahydrocannabinol, or THC, the main active chemical in cannabis. Unlike LSD and the so-called “classic psychedelics”, THC acts similarly to a different class of neurotransmitters called endocannabinoids, which send signals “backwards” across synapses in the brain to regulate neuronal firing. The effects of THC include changes in perception, appetite, and mood; “inconceivable force of tortures or of happiness” as Ludlow described it. But, is this experience “psychedelic”?

Let’s consider the classic psychedelics, like LSD and psilocybin, the main active compound in magic mushrooms. A well known effect of these psychedelics is an increase in the complexity or “diversity” of neural activity. According to one theory, brain complexity during the psychedelic state reflects the increased richness of subjective experience. In short, your experience of the world becomes more complex on psychedelics, and so to does the electrical activity of your cerebral cortex.

The Science of Psychedelic Effects: THC vs. Classic Psychedelics

Recently published work led by my collaborator Conor Murray at UCLA investigated whether oral THC would also increase neural complexity. While at the University of Chicago, Murray and his colleagues recorded electrical brain activity using a non-invasive technology called EEG while one group of healthy volunteers took THC in pill form and another group took a tiny “microdose” of the classic psychedelic LSD in another session (a microdose here means a tiny dose with barely noticeable effects). Note that this THC pill contained synthetic THC, or Marinol, rather than extract from the cannabis plant. Marinol doesn’t contain other cannabis compounds like CBD, and so its effects may be different from those of real cannabis products. Furthermore, some individuals have a genetic background which impairs their liver’s ability to metabolize THC, and these people will be more impacted by oral THC than smoked or vaped THC.  

To also examine how LSD and oral THC compared to a stimulant drug that lacks perception-altering effects, the University of Chicago researchers gave a third group of healthy volunteers a medical preparation of methamphetamine. This medical preparation, similar to what is occasionally prescribed for attention deficit hyperactivity disorder or ADHD, isn’t smoked like “crystal meth”, the drug’s street form, but it still has powerful effects on alertness and attention. For all drugs given in the laboratory—THC, LSD, and methamphetamine—some volunteers took the real drug while others took an inactive placebo.

So, how did these drugs affect the volunteers? When asked how much they felt the drug effect, volunteers felt the most “high” during the THC session, something like a solid 6 or 7 if rated on a scale out of 10. Both the methamphetamine and LSD drug effects were weaker, which isn’t too surprising given that the LSD was only given as a microdose. Furthermore, both THC and LSD increased anxiety, though this effect was stronger in the case of THC.

Exploring Neural Complexity: Does THC Alter Brain Activity Like Psychedelics?

But what about effects on brain activity? I contributed to the study by guiding an analysis of neural complexity. Surprisingly, when each drug’s effect on neural complexity was compared with a placebo, only LSD caused a statistically significant increase in the complexity of brain activity. THC simply did not alter the complexity of EEG signals at significant level, and the small effects it did exert were a mixture of increases and decreases at different EEG sensors.

Psychedelic, or Not? Subjectivity Matters

So, does this mean that oral THC and edible cannabis products aren’t psychedelic? Not so fast. First of all, the changes in complexity observed with LSD didn’t correlate with the drug’s subjective effects, which suggests that the diversity of neural signals changes even before strong effects in one’s mental experience occur. However, this might have been different if participants had been given a larger, “macrodose” of LSD, as other studies have found correlation between neural complexity and the felt effects of macrodosed psychedelics.

Additionally, it’s important to remember that volunteers took Marinol, which lacks the other natural chemicals or “cannabinoids” found in the cannabis plant, such as CBD. Although the main effects of cannabis are exerted by THC, it’s possible that THC also interacts with other cannabinoids, which alter its effects. In other words, a different study using extracts from the cannabis plant might have yielded different results.

is cannabis psychedelic? -- man sits with blindfold after using cannabis surrounded by candlelights.

The Potential Role of Cannabis in Psychedelic Therapy

But finally, and most importantly, we need to remember what the word psychedelic means: to manifest the mind. Many experiences, including some that don’t involve any drugs, reveal hidden aspects of the mind, including meditation, breathwork, and floating in a sensory reduction float tank. In the case of meditation, it’s somewhat unclear whether this activity is accompanied by increases or decreases in neural complexity. But as far as a psychedelic quality is concerned, the ground truth in each case is whatever a person reports: if experiences with meditation or cannabis seems to manifest hidden aspects of the mind, then why can’t we call these experiences psychedelic?

Nonetheless, I think Murray’s recent EEG study of THC has important implications for psychedelic therapy. Psychotherapy, assisted by classic psychedelic compounds like LSD and psilocybin, is now being studied in many countries as a treatment for depression, addiction, and anxiety surrounding terminal illness. All clinical trials must compare these compounds to an inactive placebo (a pill with no effects) to determine if any benefit the patient experiences is really due to the drug or just due to what the patient expects will happen, a self-fulfilling prophesy of sorts. Because most psychiatric drugs have rather subtle effects—you don’t really notice much after popping a Prozac pill—placebo controlled trials generally work well. Classic psychedelics like LSD, on the other hand, have extremely obvious effects—participants know when they’re assigned to the placebo group, which alters their expectations of whether their symptoms will improve.

One solution to this problem would be to use an active placebo—a compound with noticeable, yet different, effects than a classic psychedelic drug like LSD. An active placebo would be as similar as possible to LSD without actually sharing its possible therapeutic properties. Drugs that act at the 5HT2a receptor, like LSD and psilocybin, are not merely psychedelic; they also increase the brain’s capacity to change and rewire itself, which is likely key to their ability to help pull people out of depression. In this context, the drugs are known as “psychoplastogens”. Cannabis, on the other hand, is not a psychoplastogen—as bizarre as a given experience with cannabis may be, it is unlikely to trigger massive rewiring of the brain comparable to changes induced by LSD. And yet, it may cause strong alternations in perception, which follow a long time course when taken orally (as a pill or edible) similar to classic psychedelics, often needing up to an hour or two to start after the oral dose is consumed. This might make cannabis a better comparison in psychedelic drug trials than a simple, inactive placebo. In such a trial, it would be less obvious to participants which treatment they had been assigned to, helping to control for expectancy effects.

Regardless of whether neural complexity changes track how psychedelic a substance feels, its specificity to LSD in Murray’s study suggests that it might be a biomarker specific to effects caused by LSD and not THC. If future studies show that neural complexity tracks some therapeutic property of LSD that THC lacks, then clinical trials of psychoplastogens might use neural complexity to differentiate between effects of the treatment versus another psychoactive drug used as a control, like oral THC. This idea is supported by the fact that ketamine, another psychoplastogen with antidepressant properties (albeit one that does not act at 5HT2a receptors) is also known to increase neural complexity.

Defining ‘Psychedelic’ and the Importance of Respectful Use

At the end of the day, the question of whether cannabis, edible or otherwise, is “psychedelic” is really a matter of semantics—how do we define psychedelic? And whether or not it’s regarded as psychedelic, THC shows both important differences and similarities with classic psychedelics like LSD. While these drugs have different uses and risks, THC may be comparable enough with classic psychedelics to serve the much needed purpose of providing a psychoactive control in psychedelic therapy.

Finally, whether or not you consider cannabis to be psychedelic, it and other psychoactive substances should be treated with respect and caution. Drugs discussed in this article have the ability to alter the mind, which, depending on the context and intentions behind their use, can be either therapeutic or harmful.

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Aesthetic chills mitigate maladaptive cognition in depression-- an important finding showcasing the power of positive affect promotion.

Aesthetic chills mitigate maladaptive cognition in depression

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Schoeller, F., Jain, A., Adrien, V., Maes, P., & Reggente, N. (2024). Aesthetic chills mitigate maladaptive cognition in depression. BMC Psychiatry, 24(1). https://doi.org/10.1186/s12888-023-05476-3

“Aesthetic Chills Mitigate Maladaptive Cognition in Depression.” BMC Psychiatry, vol. 24, no. 1, Jan. 2024, https://doi.org/10.1186/s12888-023-05476-3.

@article{Schoeller_Jain_Adrien_Maes_Reggente_2024c, title={Aesthetic chills mitigate maladaptive cognition in depression}, volume={24}, url={https://doi.org/10.1186/s12888-023-05476-3}, DOI={10.1186/s12888-023-05476-3}, number={1}, journal={BMC Psychiatry}, author={Schoeller, Félix and Jain, Abhinandan and Adrien, Vladimir and Maes, Pattie and Reggente, Nicco}, year={2024}, month=jan }

Using peak positive affect (aesthetic chills) to help with depression

In our recent collaboration with Pattie Maes’s Fluid Interfaces group at MIT Media Lab and Dr. Vladimir Adrien from Assistance Publique Hôpitaux de Paris (APHP) in France, we investigated the potential for aesthetic chills to serve as an innovative intervention for major depressive disorder. This effort is a considerable advancement towards the notion of promoting positive affect in depression, which stands in contrast to standard care which is mostly focused on mitigating negative affect.

Instead of focusing on how to help individuals with depression not feel so bad, this work suggests the potential of helping those individuals by presenting them with content so they can feel good.

Aesthetic chills are characterized by sensations like shivers, goosebumps, and tingling that arise in response to emotional experiences with art, music, or nature. We hypothesized that by eliciting chills through validated multimedia stimuli, we could positively influence the core beliefs and self-schemas of individuals with depression. Across two studies with 96 participants diagnosed with major depressive disorder, we engaged participants in randomized sessions involving chill-inducing and neutral control stimuli across visual, auditory, and written modalities. Our results demonstrated that aesthetic chills induced a notable increase in self-acceptance among depressed participants. Chill-inducing stimuli appeared to facilitate positive emotional breakthroughs and shifts in self-perception that could address cognitive distortions related to depression. The data further suggest that aesthetic chills may engage reward-related neural pathways similarly to interventions like psychedelic-assisted therapy.

Individuals with major depressive disorder reported more emotional breakthroughs in their maladaptive cognition (e.g., lack of self-acceptance) when they reported getting chills compared to individuals who viewed the same content, but didn’t get chills. This also scaled as a function of the intensity of those chills.

While preliminary, these findings bring much-needed attention to the potential for aesthetic chills to positively influence core beliefs and schemas related to the self and one’s place in the world. For individuals with depression stemming from early adverse experiences, chill-inducing stimuli could foster emotional catharsis and lasting change to maladaptive self-narratives developed as coping mechanisms. Our research provides initial evidence that the biological processes involved in aesthetic chills can be harnessed for therapeutic ends. Chill-based interventions offer a promising avenue for large-scale study given the ease of dissemination through multimedia experiences.

Looking forward, further research should explore the neurophysiological mechanisms of aesthetic chills and biomarkers that may predict individual responses. Larger clinical trials are needed to investigate optimal protocols and delivery methods for chill-based therapy. We believe aesthetic chills represent an innovative non-pharmacological intervention that warrants greater attention from the psychiatry, psychology, and human-computer interaction communities.

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Interoceptive Technologies for Psychiatric Interventions: A Comprehensive Review

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Schoeller, F., Horowitz, A. H., Jain, A., Maes, P., Reggente, N., Christov-Moore, L., . . . Friston, K. J. (2024). Interoceptive technologies for psychiatric interventions: From diagnosis to clinical applications. Neuroscience & Biobehavioral Reviews, 156, 105478. https://doi.org/10.1016/j.neubiorev.2023.105478

Schoeller, Félix, Adam Haar Horowitz, et al. “Interoceptive Technologies for Psychiatric Interventions: From Diagnosis to Clinical Applications.” Neuroscience & Biobehavioral Reviews, vol. 156, Jan. 2024, p. 105478. https://doi.org/10.1016/j.neubiorev.2023.105478.

@article{Schoeller_Horowitz_Jain_Maes_Reggente_Christov-Moore_Pezzulo_Barca_Allen_Salomon_et al._2024, title={Interoceptive technologies for psychiatric interventions: From diagnosis to clinical applications}, volume={156}, url={https://doi.org/10.1016/j.neubiorev.2023.105478}, DOI={10.1016/j.neubiorev.2023.105478}, journal={Neuroscience & Biobehavioral Reviews}, author={Schoeller, Félix and Horowitz, Adam Haar and Jain, Abhinandan and Maes, Pattie and Reggente, Nicco and Christov-Moore, Leonardo and Pezzulo, Giovanni and Barca, Laura and Allen, Micah and Salomon, Roy and Miller, Mark and Di Lernia, Daniele and Riva, Giuseppe and Tsakiris, Manos and Chalah, Moussa A. and Klein, Arno and Zhang, Ben and Garcia, Teresa and Pollack, Ursula and Trousselard, Marion and Verdonk, Charles and Dumas, Guillaume and Adrien, Vladimir and Friston, Karl J.}, year={2024}, month=jan, pages={105478} }

What Is Interoception?

Interoception refers to our awareness of internal bodily signals like heartbeat, breathing, and digestion. While often overlooked, emerging research is revealing interoception as a fundamental process underlying emotion, cognition, and mental health. A new multidisciplinary review led by IACS senior research scientist Felix Schoeller and published in Neuroscience & Biobehavioral Reviews explores the profound significance of interoception and its potential applications in psychiatric diagnosis and treatment.

Directly manipulating interoceptive signals in experiments has proven challenging due to the highly invasive techniques currently used, like esophageal balloon distension. There is also a lack of standardized, validated measures of interoceptive function across research disciplines as “the lack of correlation across unimodal tests underscores the need for multimodal approaches that assess integration of interoceptive information across bodily systems.” Drawing from fields like psychology, physiology, psychiatry, engineering, and neuroscience, the article provides a detailed account of the neurobiology of interoception, describing it as a hierarchical predictive processing system in the brain, and emphasizing the key role of dysfunctional interoceptive processing in disorders like anxiety, depression, and eating disorders.

What are Interoceptive Technologies?

The review also explores in details existing paradigms for modulating interoception, like interoceptive conditioning. This involves pairing internal bodily sensations with aversive stimuli to reshape emotional and physiological responses through a form of classical conditioning. The authors discuss clinical applications of these approaches, such as interoceptive exposure therapy for anxiety disorders. They also propose a new classification system for interoceptive technologies, dividing them into three categories: artificial sensations that induce novel bodily perceptions, interoceptive illusions that manipulate the precision of predictions, and emotional augmentation systems that facilitate beneficial changes in beliefs or behaviors.

interoceptive technologies examples

Figure 1. Overview of interoceptive technologies: A) the breath-holding test as an artificial sensation, whereby some bodily signal is directly manipulated, B) false heart feedback as an interoceptive illusion, where contextual cues generate a perceptual drift (here the illusion that the heart beats faster at a faster-than-expected rate), C) the therapeutic alliance as entrainment, where the patient’s heart rate slows down as the therapist’s is increasing, leading both to tend towards some average value, D) augmented exposure therapy as emotional augmentation, similar to B but with additional exteroceptive cues having personal significance to the individual (e.g. eliciting the trauma-related memory) favoring an emotional explanation for the interoceptive drift.

Such technologies could have powerful implications. Artificially inducing bodily sensations could help diagnose psychiatric conditions by testing patients’ susceptibility to developing skewed predictions about their internal state. More advanced emotional augmentation systems could precisely modulate predictive processes to reshape maladaptive cognitions and behaviors. While acknowledging that much remains unknown, the review shows the vast potential for interoceptive interventions to improve diagnosis and treatment of mental health disorders. Developing standardized measures and new technologies to precisely manipulate interoceptive signaling may open transformative frontiers in biological psychiatry and psychology.

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New research sheds fresh light on mystery of infant consciousness

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Bayne, T., Frohlich, J., Cusack, R., Moser, J., & Naci, L. (2023). Consciousness in the cradle: on the emergence of infant experience. Trends in Cognitive Sciences.

Bayne, Tim, et al. “Consciousness in the cradle: on the emergence of infant experience.” Trends in Cognitive Sciences (2023).

@article{bayne2023consciousness, title={Consciousness in the cradle: on the emergence of infant experience}, author={Bayne, Tim and Frohlich, Joel and Cusack, Rhodri and Moser, Julia and Naci, Lorina}, journal={Trends in Cognitive Sciences}, year={2023}, publisher={Elsevier} }

New research sheds fresh light on mystery of infant consciousness

When does consciousness begin? There is evidence that some form of conscious experience is present by birth, and perhaps even in late pregnancy, an international team of researchers led by Tim Bayne of Monash University in Melbourne, Australia and Joel Frohlich of the University of Tuebingen in Germany and the US-based Institute for Advanced Consciousness Studies in Santa Monica, California has concluded in a new review manuscript. The findings, just published in the peer-reviewed journal ‘Trends in Cognitive Science’, have important clinical, ethical, and potentially legal implications, according to the authors.

In the study, entitled ‘Consciousness in the cradle: on the emergence of infant experience’, the researchers argue that, by birth, the infant’s developing brain is likely capable of conscious experiences. Although each of us was once a baby, infant consciousness remains mysterious, because infants cannot tell us what they think or feel, explains one of the two lead authors of the paper Dr. Tim Bayne, Professor of Philosophy at Monash University. 

“Nearly everyone who has held a newborn infant has wondered what, if anything, it is like to be a baby. But of course we cannot remember our infancy, and consciousness researchers have disagreed on whether consciousness arises ‘early’ (at birth or shortly after) or ‘late’ ­– by one year of age, or even much later.”

To provide a new perspective on when consciousness first emerges, the team reviewed recent advances in consciousness science. In adults, some markers from brain imaging have been found to reliably differentiate consciousness from its absence, and are increasingly applied in science and medicine. This is the first time that these advances, as translated to infants, have been reviewed in detail.

Co-author of the study, Dr. Lorina Naci, Associate Professor at Trinity College Dublin in Ireland, who leads the ‘Consciousness and Cognition Group’, explained: “Our findings suggest that newborns can integrate sensory and developing cognitive responses into coherent conscious experiences to understand the actions of others and plan their own responses.”

It is even possible that birth itself triggers the onset of consciousness. “Probably the first thing the newborn infant realizes is that the outside world is very unpredictable relative to the womb environment,” explained co-lead author and postdoctoral researcher  Dr. Joel Frohlich. “Things are constantly changing, and so the newborn must build a mental model of the world to adapt and predict things.” 

However, the authors don’t rule out the possibility that consciousness might already start some weeks beforehand.  “Julia Moser’s work shows that third-trimester fetuses appear to be capable of learning sequences of auditory beeps,” said Dr. Frohlich, referring to his co-author Dr. Moser at the University of Minnesota. “When an auditory tone deviates from a pattern established earlier in the experiment, the fetus shows this ‘surprise’ response in its magnetic brain activity. The neural activity shows a field deflection as if the fetus is saying ‘huh?’.”

The paper also sheds light into ‘what it is like’ to be a baby. We know that seeing is much more immature in babies than hearing, for example (see the image below for a theoretical depiction). Furthermore, this work suggests that, at any point in time, infants are aware of fewer items than adults, and can take longer to grasp what’s in front of them, but they can easily process more diverse information, such as sounds from other languages, than their older selves. 

infant consciousness differences in perception

“Infants can perceive many things which adults cannot, like the differences between vowel sounds in a foreign language,” explained Dr. Joel Frohlich. “By 10 months or so, we lose this ability as the brain decides these perceptual differences are no longer relevant and discards them.” 

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